Variable Air Volume Modular Assembly (VMA) 1400 Series

Application Note
Issue Date
April 29, 2004
Variable Air Volume Modular Assembly (VMA)
1400 Series
Using Variable Air Volume Modular Assembly (VMA) 1400 Series
Applications ...........................................................................................2
Introduction......................................................................................................... 2
Key Concepts...................................................................................................... 3
VMA Controller.................................................................................................................. 3
Theory of Operation .......................................................................................................... 7
Application Logic ............................................................................................................. 11
VMA Single Duct Applications......................................................................................... 21
VMA Dual Duct Applications ........................................................................................... 27
VMA Diagnostics............................................................................................................. 41
Detailed Procedures......................................................................................... 45
Creating a VMA Single Duct Application ......................................................................... 45
Creating a VMA Dual Duct Application ........................................................................... 56
Changing the VMA Parameter View ............................................................................... 63
Configuring a VMA Application ....................................................................................... 64
Commissioning a VMA Application ................................................................................. 64
Testing and Balancing a VMA Single Duct Supply/Exhaust Application ......................... 65
Testing and Balancing a VMA Dual Duct Application ..................................................... 68
Troubleshooting ............................................................................................... 73
VMA Firmware Revisions ................................................................................................ 78
Attributes and Parameters............................................................................... 80
Input/Output Options ....................................................................................................... 80
VMA Single Duct Parameters ......................................................................................... 89
VMA Dual Duct Parameters .......................................................................................... 111
© 2004 Johnson Controls, Inc.
Code No. LIT-6375125
www.johnsoncontrols.com
HVAC PRO Software Release 8.05
2
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Using Variable Air Volume
Modular Assembly (VMA)
1400 Series Applications
Introduction
The Variable Air Volume Modular Assembly (VMA) 1400 Series is
an integrated module that includes a controller, differential pressure
sensor, and actuator (except VMA1430 models, which are intended to
be used with an external actuator).
Note:
This document focuses on the VMA1410, 1420, and 1430
controllers. The VMA1400 Series also includes the VMA1440, which
is used exclusively as part of the Metasys® Zoning Package. Refer to
the Metasys Zoning Package Product Bulletin (LIT-639050) and the
Metasys Zoning Package Overview Technical Bulletin (LIT-639100)
for information on this specialized product.
This application note introduces the VMA controller and provides
procedures for the creation, configuration, and commissioning of
single duct and dual duct applications.
This document describes how to:
•
create a VMA single duct application
•
create a VMA dual duct application
•
change the VMA parameter view
•
configure a VMA application
•
commission a VMA application
•
test and balance a VMA single duct supply/exhaust application
•
test and balance a VMA dual duct application
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
3
Key Concepts
VMA Controller
Description
The Variable Air Volume Modular Assembly (VMA) models
VMA1410 and VMA1420 are integrated modules that include the
controller, actuator, and differential pressure sensor. The VMA1430
includes the controller and differential pressure sensor and is designed
for use with a floating/3-wire (incremental) external actuator or
proportional external actuator. The VMA applications are developed
using standard objects, assembly objects and application objects
created by the Metasys system application basic programming
language. These applications are built using Configuration Tools
Release 7.00 or later, and are downloaded to the VMA. The VMA1430
is supported at Configuration Tools Release 7.02 or later.
Note:
This document focuses on the VMA1410, 1420, and 1430
controllers. The VMA1400 Series also includes the VMA1440, which
is used exclusively as part of the Metasys Zoning Package. Refer to
the Metasys Zoning Package Product Bulletin (LIT-639050) and the
Metasys Zoning Package Overview Technical Bulletin (LIT-639100)
for information on this specialized product.
VMA1410
VMA1420
VMA1430
VMA14xx
Figure 1: VMA Controller Models
VMA applications can only be used with the VMA. These applications
cannot be downloaded to any other digital controllers, such as the
Unitary (UNT), Variable Air Volume (VAV), or Air Handling Unit
(AHU) controllers.
4
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Integral Stepper Motor Actuator
The stepper motor damper actuator is an integral part of the
VMA1410/1420. The stepper motor provides a fast and accurate
method of controlling the damper actuator. At startup, the VMA is
programmed to perform an autocalibration procedure. This procedure
occurs on a variable time delay determined by the N2 address.
Autocalibration corrects for pressure sensor drift and ensures the
stepper is synchronized. As part of the initial autocalibration, the
stroke time of the integral actuator is calculated based on the time
required to move from the open end-stop to the closed end-stop. The
stroke time should be roughly equal to one of the following:
30 seconds for 90 degree dampers
20 seconds for 60 degree dampers
15 seconds for 45 degree dampers
The VMA requires physical end-stops on both ends of rotation for
correct operation.
During normal operation, the actuator position feedback provides
position information and diagnostics that can indicate a stuck damper
or slippage at the damper shaft connection. For the dual duct
application, the VMA1420 with an integral actuator (if used) must be
used on the cold deck damper.
External Damper Actuators
The VMA1420/30 can control external floating/3-wire (Position
Adjust Output [PAO]) or proportional damper actuators in VAV
boxes, such as Trane® company boxes. Two Binary Outputs (BOs) are
used for each floating/3-wire (PAO) actuator. One Analog Output
(AO) is used for each proportional actuator.
Note:
External actuators require configuration of the stroke time
attribute for the actuator to operate properly.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Revisions
Table 1 compares HVAC PRO software revisions and VMA
application revisions. See the Troubleshooting section of this
document for more information on VMA firmware revisions.
Table 1: Revisions
HVAC PRO
Software Revision
VMA Application
Revision
Description of Changes
7.00
2
Original Release
7.01
3
•
Units attribute added for flow parameters.
•
State machine fixes to prevent stuck conditions:
- VAV Box mode
- Heating mode
•
State machine fix to prevent Cooling state when a
constant volume box (maximum flow is achieved during
Satisfied state).
•
Autocalibration Duration is now calculated automatically.
•
Additional actuator support for flow control loop:
- Floating/3-wire
- Proportional
•
Users must set a new attribute for proportional actuators
Stroke Time.
7.02
4
7.03
4
8.00
Single Duct – 4
Support added for TMZ Digital Room Sensor.
Dual Duct – 1
Original release of dual duct application
Single Duct – 4
Supply exhaust application added to single duct application.
Dual Duct – 2
Application fix to correct error with proportional band reset
Single Duct – 5
•
State machines moved to sub-application to enable large
supply/exhaust applications to download.
•
Optional minimum flow protection added for proportional
(AO, Duration Adjust Output [DAO]) box heating outputs.
•
Schedule attribute added to Occupancy Mode (ADI 78)
for network command. If N2 communication fails, the
Occupancy Mode Input is the default mode. See the Key
Concepts section for complete description.
•
Setpoint threshold added to enable application to bypass
state machine saturation timers when a large setpoint
change occurs.
•
Configurable maximum damper positions added for
pressure dependent mode.
•
Pattern Recognition Adaptive Control (PRAC) disabled
for Proportional-Integral-Derivative (PID) control loops
dependent on flow when Starved Box flag is True.
•
Min PID Prop Band limit added to provide a lower tuning
limit for PRAC.
•
Sideloop PID Direct Acting parameter mapped (BD 171)
8.01
8.03
Changes to both
applications:
Single Duct – 5
Dual Duct – 3
Continued on next page . . .
Application fix to correct error in pressure dependent
operation
5
6
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
HVAC PRO
Software Revision
(Cont.)
VMA Application
Revision
Description of Changes
8.04
Single Duct - 5
Support for TE-7700.
Changes to both
applications:
Single Duct – 5
Dual Duct – 3
TMZ setpoint allows wider ranges of 7 to 32°C (45 to 90°F).
Note: The TMZ must be at firmware revision A08 or later to
take advantage of this feature.
Single Duct – 5
•
Support added for autocalibration using BO activated
solenoid air valve that zeros the differential pressure
across the velocity pressure sensor(s).
•
VAV Box Mode sequencing updated to ensure
application remains in heating ,at minimum, for the PID
low saturation time.
8.05
Related Documentation
Table 2 lists related VMA documentation.
Table 2: Related Documentation
For Information on This
Refer To
VMA Product Information
Variable Air Volume Modular Assembly (VMA) 1400 Series Product
Bulletin (LIT-635058)
VMA Installation Information
VAV Modular Assembly (VMA) 1410/1420 Installation Instructions
(Part No. 24-8740-1) - packed with VMA1410 and VMA1420
VAV Modular Assembly (VMA) 1430 Installation Bulletin
(Part No. 24-8986-18) - packed with product
VMA Technical Information
Variable Air Volume Modular Assembly (VMA)1400 Series Overview and
Engineering Guidelines Technical Bulletin (LIT-6363120)
Mounting and Wiring Variable Air Volume Modular Assembly (VMA)1400
Series Controllers Technical Bulletin (LIT-6363125)
Downloading and Commissioning the Variable Air Volume Modular
Assembly (VMA)1400 Series Controllers Technical Bulletin (LIT-6363130)
Troubleshooting Variable Air Volume Modular Assembly (VMA)1400 Series
Controllers Technical Bulletin (LIT-6363135)
Commissioning Tool User
Information
HVAC PRO User’s Guide
Connecting the N2 Bus
N2 Communications Bus Technical Bulletin (LIT-636018)
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
7
Theory of Operation
VAV System
A VAV air handling system typically consists of a single air handling
unit and multiple terminal units. Terminal units typically consist of a
damper and flow sensing probe installed in an enclosure. VAV
terminal units are also called VAV boxes. VAV systems are
predominantly single duct, but about 15% are dual duct designs. In
either case, the supply air temperature and static pressure of the air
handling unit are controlled by an AHU controller, while each zone
has its own VMA controller.
The air handling unit typically maintains a static pressure in the range
of 125 to 375 Pa (0.5 to 1.5 inches w.c.) inside the longest run of duct
away from the supply fan. This ensures that each VAV terminal unit
has enough pressure at its inlet to deliver the maximum required flow
of air into the space. The supply temperature is typically in the range
of 7 to 16°C (45 to 60°F) for a single duct VAV system or the cold
deck of a dual duct VAV system. The hot deck temperature of a dual
duct VAV system is typically in the range of 29 to 49°C (85 to 120°F).
VAV systems are most easily understood by first considering a cooling
only application. As the zone temperature increases, the VAV
controller opens the VAV box damper to allow more cool air to reach
the space. The volume of air required to maintain a particular zone
temperature setpoint is dictated by the size of the space and the
internal and external heat loads. In addition, since the size of the VAV
box dictates its maximum cooling capacity, a VAV box’s performance
is dependent upon the mechanical engineer’s correct box sizing for
each zone.
Sometimes the size, and thus the capacity, of the VAV box may not
match the zone loads. If the installed unit is too small, insufficient
cooling results and audible noise may be emitted at high flow. If the
installed unit is too large, proper control may be difficult to attain,
since a small change in damper position causes a large change in
airflow. Boxes can be oversized to allow for quieter operation or
reserve cooling capacity at the expense of controllability. For a more
in-depth explanation of VAV control, refer to the Variable Air Volume
Modular Assembly (VMA) 1400 Series Overview and Engineering
Guidelines Technical Bulletin (LIT-6363120).
8
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Control Loops
Pressure Independent Control
In Cooling mode, the VMA employs cascaded control loops. The zone
temperature control loop is achieved by using Proportional-Integral
(PI) control loops with Pattern Recognition Adaptive Control (PRAC)
to tune the controller. The output of the temperature loop is used to
calculate the airflow setpoint between the minimum and maximum
flow settings. This airflow setpoint is used by the flow control loop
that is implemented using the Johnson Controls® patented
Proportional-Adaptive (P-Adaptive) algorithm. The flow control loop
allows the temperature control to be independent of duct static
pressure.
Proportional-Integral-Derivative (PID)
The Heating, Ventilating, and Air Conditioning (HVAC) industry uses
PID feedback control algorithms. The derivative portion is available in
the VMA, but it is typically not used because it can amplify noise and
lead to instability. Thus, PI algorithms are most commonly used in
actual installations. PI control algorithms have two parameters that
affect controller performance: proportional gain and integral time.
The HVAC controls’ manufacturer typically uses default PI control
parameters shipped with the controller. The default parameters may
not be appropriate, and using them can lead to poor control
performance. Also, many control loops require frequent re-tuning
because HVAC systems have time-varying dynamics. These dynamics
are caused by the inherent non-linear behavior of HVAC system
components and the time-varying nature of the load disturbances. The
loads for HVAC systems change with time or season.
Pattern Recognition Adaptive Control (PRAC)1
The VMA uses a Johnson Controls patented PRAC algorithm to tune
its PI feedback loops. The PRAC algorithm automatically adjusts the
proportional band and the integral time of a PI control loop based on
patterns of the sensed values from the process variable, setpoint, and
the output of a PID control loop. PRAC uses a measure of the system
damping and response speed of the process output to characterize the
closed loop response with respect to different setpoint changes and
load disturbances, resulting in near-optimal closed loop control
performance. PRAC automatically adjusts to different process noise
levels, has minimal calculation and memory requirements, and is
easily implemented.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
9
Using PRAC reduces commissioning time for new control systems,
eliminates operator time for re-tuning control loops and increases
actuator life, as it reduces motor runtime.
PRAC is used to tune the zone temperature control loop in pressure
independent applications. When two-position valves or electric heat is
selected, PRAC is not loaded. PRAC is enabled or disabled via a
software command. PRAC is disabled at saturation, upon an error, and
during an override situation. If a derivative time value other than zero
is detected in a PID control loop, PRAC does not attempt to tune the
controller.
Starting with Application Revision 5 for single duct and Application
Revision 3 for dual duct applications, PRAC is also disabled if the
active PI does not have sufficient flow to maintain control (for
example, Starved Box is True). This means that in single duct
applications, the Cooling PID is disabled if Starved Box is True.
Similarly, the Box Heating PID for single duct applications is disabled
if Starved Box is True and there is no box fan active. In dual duct
applications, the Energy Balance PID is disabled if either Starved Cold
Deck or Starved Hot Deck is True.
1
Seem, J. E., “A New Pattern Recognition Adaptive Controller”,
13th Triennial IFAC World Congress, The International
Federation of Automatic Control, San Francisco, CA., Volume K
on Adaptive Control, Session on Auto-tuning and Adaptation,
Paper 3B-043, pp. 121-126, Pergamon, 1996.
P-Adaptive Control2
The P-Adaptive flow control algorithm uses a patented fixed gain,
proportional control loop with a self-adjusting deadband whose value
is related to an estimate of the noise variance. The P-Adaptive control
strategy is used in the secondary flow control loop for pressure
independent applications. P-Adaptive control has the advantage of
much tighter flow control without oscillation, because it dynamically
adjusts the flow deadband, based on the turbulence (noise) measured
on the pressure sensor. P-Adaptive does not require any tuning.
2
Federspiel, c., 1997. “Flow Control with Electric Actuators”,
International Journal of Heating, Ventilating, Air Conditioning,
and Refrigeration Research, Vol. 3, No 3.
10
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Airflow Measurement
Airflow (supply flow) is calculated for the VMA using
two parameters: the supply box area (area at the inlet of the box where
the airflow pickup is located), and the flow pickup gain (supply pickup
gain). Appendix B: VAV Controller Flow Calculation Constants
(LIT-6375185) provides the flow pickup gain (supply pickup gain) or
K-factor for most Original Equipment Manufacturer (OEM) boxes.
With this information, the VMA calculates the airflow (supply flow)
using the following equation:
SupplyFlow =
SupplyBoxArea * FlowCoefficient *
SupplyDeltaP
SupplyPickupGain
Alternatively, if you know the supply flow and differential pressure
(SupplyDeltaP), calculate the flow pickup gain (SupplyPickupGain)
using the following equation:
SupplyPickupGain =
⎛ FlowCoefficient ∗ SupplyBoxArea ⎞
⎟⎟
SupplyDeltaP ∗ ⎜⎜
SupplyFlow
⎝
⎠
Note:
2
Exhaust flow is calculated using the same equations.
SI (Metric) Units
SupplyFlow = airflow calculated in m3/hr (liters/second in Canada)
SupplyDeltaP = differential pressure in Pascal (1 inch w.c. = 249 Pa)
FlowCoefficient = defaults to 4644 at sea level for airflow in m3/hr or
1290 at sea level for airflow in liters per second (l/s)
(These values are a function of elevation.)
SupplyPickupGain = airflow pickup gain (dimensionless)
SupplyBoxArea = area in square meters
Inch-Pound Units
SupplyFlow = airflow calculated in cubic feet per minute (cfm)
SupplyDeltaP = differential pressure (inches w.c.)
FlowCoefficient = defaults to 4005 at sea level
(This value is a function of elevation.)
SupplyPickupGain = airflow pickup gain or K-factor (dimensionless)
SupplyBoxArea = area in square feet. Calculated from 3.1416 * r2,
where r is the inlet radius in feet.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
11
The engineer or balancing contractor determines the minimum airflow
necessary for adequate ventilation. Required minimum airflow is
based primarily on the expected number of occupants in the room. The
American Society of Heating, Refrigerating, and Air Conditioning
Engineers (ASHRAE) Standard 62 recommends 34 cubic meters per
hour (20 cubic feet per minute [cfm]) of outdoor air per occupant for
office space. Typically, zone airflow minimums are set between 10%
and 20% of maximum flow. Boxes with heat may have higher
minimum heating flow setpoints. Boxes with electric heating require a
minimum airflow to avoid tripping the thermal overload protection.
Application Logic
The VMA operates in several modes. Some modes occur under normal
operating conditions, and some are commanded only by a supervisory
system. The VAV Box mode determines which PID control loops are
active and controls VMA supervisory Command modes. The current
Occupancy mode determines the current occupancy state. Velocity
pressure status and zone temperature status determine the failsoft
functioning of the VMA.
VAV Box Mode
The main mode control is the VAV Box mode. True digital logic is
used to determine the active operating mode of the VMA. A state
machine standard object integrates this logic with input and output
functions. The operation of a state machine is clearly represented using
a state diagram like that shown in Figure 2. This generic state diagram
shows the general form taken by the VAV Box mode state machine in
both the single duct and dual duct VMA applications.
State Diagram
The following is a brief explanation of how to read a state diagram.
See Figure 2 for a state diagram illustration.
A circle represents a state, and its name is listed in the circle. The
number in the circle corresponds to the state name in the enumeration
set for the present value. A rectangle with a shaded header bar
represents a super-state. A super-state allows related states to be
grouped under one heading.
Only one state can be active at any one time. The active state is also
the present value of the VAV Box mode. The present value can change
two ways. The present value is a prioritized attribute and can be
overridden to a new value. The present value is equal to the override
value with the highest priority.
12
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
When no overrides are present, the active state can change via a
transition (designated by an arc). Transitions may occur between both
states and super-states. The arc points from the current state
(or super-state) to the next state (or super-state). The next-state
function is described on each arc. The next-state function must be True
for the transition to occur. Any input not listed for a particular
transition is a “don’t care” condition, meaning that transition can occur
regardless of the current value of any input that is not listed.
If the transition leaves from a super-state, the transition can occur if
any of the individual states within that super-state are active. If a
transition goes to a super-state, then that super-state must have an
entry state defined. This state is designated in the diagram by a large
dot with an arrow pointing at the entry state. When more than
one level of hierarchy is defined, a super-state may be defined as the
entry state for a higher level super-state.
VAV Box Mode
Command Modes
0
1
Shutdown
Closed
Shutdown
Open
Override Closed
Override Open
No Overrides
Auto Modes
Transition 2
2
3
State A
State B
Entry
State
Entry
State
Transition 1
boxmode
Figure 2: VAV Box Mode State Diagram
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
13
Autocalibration
Autocalibration first occurs after a reset of the controller. A reset is a
cycle of the controller power which causes a refresh of the memory. A
reset also occurs after an application download. During the first
autocalibration, the integrated actuator fully opens and then fully
closes to measure the stroke time. If needed, you can disable this
autorange test by setting the Startup Autorange parameter to False. If
you disable the autorange test, however, you must manually configure
the stroke time for rotations other than 90 degrees (see the Integral
Stepper Motor Actuator section under Key Concepts in this document
for more information).
During normal autocalibration, the actuator closes during the actuator
stroke time plus sensor settling time, and then the differential pressure
sensor analog input offset adjusts to give a velocity pressure reading of
zero. For the dual duct application, both pressure sensors autocalibrate
at the same time.
For the single duct supply/exhaust application, when you also select an
exhaust box, both pressure sensors autocalibrate at the same time. Due
to the critical flow requirements of most supply/exhaust
configurations, the autocalibration period default is set to zero to allow
the user to manually command autocalibration (using the Autocal Req
attribute) at a time when the zone is not occupied and the dampers are
closed.
Starting with HVAC PRO 8.05 and later, another option is available
for autocalibration using a BO to actuate a solenoid air valve when the
sensor calibration is active instead of closing the damper. During
autocalibration, the BO is set active for approximately 24 seconds
(8 times the On Pulse Count. See VMA Single Duct Parameters). At
the end of that time period, a new offset calculates for the Differential
Pressure (dP) sensor(s). The flow controller is prevented from moving
the damper actuator while the BO is active and for approximately
8 seconds after the BO deactivates. This allows the normal differential
pressure signal to restore before returning control to the flow
controller. For supply/exhaust applications, both pressure sensors
autocalibrate at the same time. Dual duct applications do not currently
support this feature.
Install the solenoid in an arrangement similar to Figure 3. When the
solenoid air valve is active and the normally closed port opens to the
common port, the low-pressure pickup port connects to both ports of
the dP sensor so that the sensor receives a zero differential pressure.
14
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Flow
c
Solenoid Valve
no
nc
dP Sensor
Duct
Figure 3: Solenoid Air Valve Installation
Note:
The solenoid air valve must accommodate very low
pressures (less than 1.5 inches w.c. [375 Pa]). It must not require
higher pressures to properly seal or operate.
The VMA staggers autocalibration following reset so that several
controllers do not autocalibrate at the same time. The autocalibration
delay is a function of the restart delay. Subsequent autocalibration
occurs based on the autocalibration period. The default period is two
weeks for normal applications and zero (disabled) for supply exhaust
applications. When using the BO option, configure the autocalibration
period to that given in the job specification (typically a 3-hour period
provides sufficient accuracy).
Note:
If the resultant AI offset is large (greater than 1), verify the
rotation of the VAV Box Damper using Box Flow Test with the AI
offset reset to zero.
Occupancy Mode
Occupancy mode has three possible states: Occupied, Unoccupied, and
Standby (Table 3). The state depends on the input received from
binary inputs, such as window contact, occupancy sensor, or
temporary occupancy button. Communications status with a
supervisory system, and commands from a supervisory system to the
Occupancy mode request, also affect the Occupancy mode.
Table 3: Occupancy Modes
Mode
Description
Occupied
When the mode is Occupied, the zone temperature and flow rate
controls use the occupied setpoints.
Unoccupied
When the mode is Unoccupied, the zone temperature and flow
rate controls use the unoccupied setpoints.
Standby
When the mode is Standby, the zone temperature control uses
the standby temperature setpoints and the flow rate control uses
the unoccupied setpoints.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
15
Rules for Occupancy Mode
Occupancy mode is determined by the following set of rules. If the
first rule does not apply, then the second rule is evaluated and so on
down the list. Information content and quality are the principles upon
which these rules are based. The following rules begin with the highest
priority first and involve actions with the most information content,
meaning the operator, occupant, or sensor is required to take an action.
Note:
For TMZ Digital Room Sensors, refer to Room Sensor with
LCD Display (TMZ1600) Installation Instructions (LIT-6363110) for
differences in operation.
1.
The Occupancy mode Present Value can be overridden. This
action takes highest priority.
2.
Occupancy Button - Next mode (timed): Unocc - Standby - Occ:
Each press of the room sensor Occupancy button changes the
Occupancy mode from its current state to the next Occupancy
mode. For this option, the occupancy status rotation order is:
a.
Unoccupied
(Light-Emitting Diode [LED] off)
b.
Standby
(LED blinks)
c.
Occupied
(LED on)
d.
Back to Unoccupied, then recycle through all three modes
Each button press also restarts the occupancy timer, which is
defaulted to 60 minutes. The Occupancy mode set by this
Occupancy button is cleared when the occupancy timer expires.
Note:
You must use a room sensor with an LED for this option.
3.
Occupancy Sensor - Occ button canceled when unocc sensed: The
Occupancy mode and the occupancy timer set by the Occupancy
button in Rule 2 is cleared if the occupancy sensor goes from
active to inactive.
4.
Occupancy Sensor - Occupied mode when occupancy sensed:
The Occupancy mode is set to Occupied if the occupancy sensor
is active.
5.
Occupancy Button - Occupied Mode (timed): Each press of the
Occupancy button restarts the occupancy timer, which is defaulted
to 60 minutes. The Occupancy mode is Occupied when set by an
Occupancy button and is cleared when the temporary occupancy
timer expires.
6.
If the Schedule attribute is commanded to a value other than No
Schedule, the Occupancy Mode is set to the Schedule value.
7.
The Occupancy mode is set to the Input attribute.
16
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Note:
The TE-6700 or TE-7000 (Europe only) requires that the
button be depressed for approximately 1.5 seconds to activate the
Occupancy mode.
Temperature Setpoints
The VMA applications support highly flexible temperature setpoint
configuration options. The single duct application uses the following
equations to determine the actual heating and cooling setpoints.
Depending on the flow setpoint configuration, the dual duct
application uses either the following equations or an alternative
method described in the VMA Dual Duct Applications topic later in
this section:
Actual Heating Setpoint = Heating Setpoint + Remote Adjustment +
Common Setpoint + Actual Heating Bias + Winter Compensation
Actual Cooling Setpoint = Cooling Setpoint + Remote Adjustment +
Common Setpoint + Actual Cooling Bias + Summer Compensation
Note:
The heating setpoint and the common setpoint are additive in
the Actual Heating Setpoint calculation. To prevent the Actual Heating
Setpoint from becoming a very large value, use either the common
setpoint or the heating setpoint, not both. The same applies to the
Actual Cooling Setpoint calculation.
Remote Adjustment
Connected to Analog Input 2, (AI2) this potentiometer input can be
configured using the User-Defined Ohms linearization to be defined as
a remote adjustment or remote setpoint. The default range for remote
adjust is ± 3°C (±°5°F). The default range for remote setpoint is
12-28°C (65-85°F). If the remote setpoint is selected, the heating,
cooling, and common setpoints should all be zero (see previous note).
If the remote adjustment is unreliable at startup, the controller
automatically uses the startup value. For remote adjustment, the
default startup value is 0°. For remote setpoint, the default startup
value is 21°C (70°F). If a reliable value is read and then the remote
setpoint becomes unreliable, the controller uses the last reliable value
received.
Common Setpoint
This setpoint provides the main supervisory setpoint if a single base
setpoint is specified. The VMA defaults to this configuration. If a
Remote Setpoint is used, the Common Setpoint defaults to zero.
Otherwise, the default Common Setpoint is equal to 21°C (70°F).
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
17
Cooling and Heating Setpoint
These setpoints serve as the main supervisory setpoints if dual base
setpoints are required. Because the VMA defaults to a single base
setpoint configuration, these setpoints have default values of zero. If
dual base setpoints are required, set the Common Setpoint to zero and
the Heating and Cooling Setpoints to the desired values. For dual
setpoints, select only those thermostats with warmer/cooler
adjustments (see previous note).
Actual Cooling and Heating Bias
Setpoint configuration for each Occupancy mode is accomplished
using the Actual Cooling Bias and Actual Heating Bias.
Summer and Winter Compensation
The summer and winter compensation allows the heating and cooling
setpoints to be reset as a function of the outdoor air temperature. The
outdoor temperature must be provided to the VMA by writing to the
network variable Outdoor Air Temp. If this variable is not written, the
summer and winter compensation are set equal to zero.
This method is sometimes used for units serving building entry areas
(for example, lobbies and vestibules). The summer compensation is
calculated by multiplying the difference that the Outdoor Air
Temperature (OAT) is above the summer setpoint by the summer
authority parameter. If the resultant value is greater than the summer
change limit, the summer compensation is clamped at the limit. The
winter compensation is calculated by multiplying the difference that
the outdoor air temperature is below the winter setpoint (SP) by the
winter authority parameter. If the resultant absolute value is greater
than the winter change limit, the winter compensation is clamped at
the limit. The summer and winter compensation parameters are then
used in the setpoint calculation described earlier.
Summer Compensation = (OAT - SP) * Summer Authority
Winter Compensation = (Winter SP - OAT) * Winter Authority
18
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Temperature Loop
Temperature status is the result of failsoft monitoring of the zone
temperature analog input. It includes states described in Table 4.
Table 4: Temperature States
State
Description
Zone
Temperature
Reliable
This state indicates the zone temperature input is reliable, and
normal zone temperature control is occurring.
Zone
Temperature
Unreliable
When the Zone Temp Unreliable state is active, the zone
temperature input is unreliable, possibly due to an open wire.
The outputs are overridden depending on the user failsoft
selection.
•
Hold Outputs: The flow setpoints and any heating outputs
are held at their last known good value.
•
Full Heating: The flow setpoint is held at the heating flow
setpoint, and all heat is energized. This is to prevent water
coil freeze up, but, over time, it may overheat the zone.
•
Full Cooling: The flow setpoint is held at the cooling
maximum flow setpoint, and all heat is off.
IMPORTANT: Possible Zone Overheat or Overcool.
When the zone temperature sensor is unreliable, over time the zone likely
overheats or overcools.
Flow Loop
Flow Loop is the result of failsoft monitoring of the supply delta
pressure analog input. When the Flow Loop is reliable, it indicates the
supply differential pressure is reliable, and normal flow control is
occurring.
The Velocity Pressure (VP) Unreliable state indicates the supply
differential pressure is unreliable. The VMA operates in a pressure
dependent mode until the supply differential pressure is reliable. For
the dual duct application, if either pressure sensor is unreliable, the
controller operates in pressure-dependent mode.
Compute the required position of the damper for the single duct
(supply only) application using the following equation:
⎛ SupplySetpoint ⎞
⎟⎟ * PDSupplyMaxPos
DamperPosition = ⎜⎜
⎝ ClgMaxFlow ⎠
For single duct applications, the supply setpoint is equal to the flow
span output during the Cooling mode (see Figure 4) and the heating
flow setpoint during the Heating modes.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
19
For single duct supply/exhaust configurations, the damper positions
are offset to aid the differential:
SupplyDamperPos =
⎛ SupplySetpo int − Differential ⎞
⎜⎜
⎟⎟ ∗ PDSupplyMaxPos
C lg MaxFlow
⎝
⎠
ExhaustDamperPos =
⎛ SupplySetpoint + Differential ⎞
⎜⎜
⎟⎟ ∗ PDExhaustMaxPos
ClgMaxFlow
⎝
⎠
The damper positions for the dual duct application are:
ColdDeckDamperPosition =
⎛ ColdDeckSetpoint ⎞
⎜
⎟ * PDColdDecMaxPos
⎝ ColdDeckMaxFlow ⎠
HotDeckDamperPosition =
⎛ HotDeckSetpoint ⎞
⎜
⎟ * PDHotDeckMaxPos
⎝ HotDeckMaxFlow ⎠
If the VP is unreliable, the setup attribute of the Stepper Motor Object
(SMO) and PAO changes from Incremental (-100 to +100) to
Positional damper command (0-100%) and controls in a pressure
dependent mode.
Flow Setpoint Configuration
IAQ Minimum Flow Setpoints
The VMA applications are designed to comply with the ventilation
rates for acceptable indoor air quality given in American Society of
Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE)
Standard 62-1999. To meet these rates, the user must first provide
some information. During commissioning, set the Occupancy
parameter equal to the occupancy level of the zone served by the
VMA controller. Occupancy level defaults to 0 people, which means
this IAQ feature is disabled unless an occupancy level is provided. The
user must also enter the outdoor air requirement value. The system
default is the value for office space from Table 2 of Standard 62-1999,
which is 10 L/s (20 cfm) per person.
20
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Both single and dual duct applications have parameters that must be
set by the supervisory system over the N2 bus to give the current
percentage of outdoor air being brought into each deck at the main air
handler. The single duct has a single parameter (OA Fraction), and the
dual duct has two parameters (CD OA Percent and HD OA Percent).
Use the design OA fraction/percentage if the air handler maintains that
fraction/percentage. If the outdoor air included in each deck may be
different or may vary in time, program the supervisory system to
calculate the actual current fraction/percentage and set these
parameters accordingly. Percent outdoor air is measured by the
Metasys Ventilation Controller Application (MVCA) or another
outdoor airflow measurement system. Percent outdoor air is not equal
to the position of the outdoor air damper or the mixing damper,
because airflow is not directly proportional to damper position. For
more information on the MVCA, see the Metasys Ventilation
Controller (MVC-2000-1) Product Bulletin (LIT-653410).
The VMA application multiplies the occupancy level by the outdoor
air requirement to determine the required ventilation rate (OA Flow
Reqmnt). When the Occupancy Mode is Occupied, the minimum flow
setpoints of the applications are adjusted based on this ventilation rate.
When the Occupancy Mode is not Occupied, the minimum flow
setpoints are calculated without adjusting for IAQ.
The single duct IAQ minimum flow is calculated using the following
equation.
IAQ Min Flow = OA Flow Reqmnt * 100 / OA Fraction
For dual duct applications, the ventilation rate is met by the sum of the
outdoor air in the hot and cold decks. If both decks have outdoor air
available (Deck Available = True and OA Percent > 0.0), then the
actual cold and hot deck minimum flow setpoints based on IAQ are
calculated to share the outdoor air requirement across both decks
taking into consideration the relative outdoor air content of each deck.
The minimum IAQ flow for each deck is calculated using the
following equations.
CD IAQ Min Flow =
OA Flow Reqmnt * 100 * CD OA Percent
CD OA Percent 2 + HD OA Percent 2
HD IAQ Min Flow =
OA Flow Reqmnt * 100 * HD OA Percent
CD OA Percent 2 + HD OA Percent 2
(
(
)
)
If only one deck has outdoor air available, the IAQ minimum flow for
that deck is calculated by dividing the ventilation rate by the percent
outdoor air of that deck (same as single duct). This IAQ strategy works
with the existing VMA applications, is easy to alter, and optimizes
energy usage by dealing with each zone independently.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
21
VMA Single Duct Applications
Control Overview
Figure 4 shows the overall control diagram for the single duct
application. The VMA application uses cascaded control loops to
achieve pressure-independent control. During the Cooling mode, the
Cool Loop uses a PID tuned by PRAC that produces an output from
0-100%. This output spans the minimum and maximum flow rate
setpoints, and is calculated using the following equation:
FlowSpanOutput = MinFlow + (MaxFlow − MinFlow ) *
PI Pr esValue
100
The output of the flow rate span block is the flow setpoint for the Flow
Loop. The flow loop uses the P-Adaptive flow controller to position
the damper to maintain the current flow setpoint.
Room Loop
Temperature
Transmitter
Cool Loop
Actual
Cooling
Setpoint
Cooling
PI with
PRAC
Flow
Setpoint
Flow
Rate
Span
Damper
and
P-Adaptive
Room
Actuator
Flow Loop
Flow
Calculation
Delta P
Box Heat Loop
Actual
Heating
Setpoint
Box Htg
PI with
PRAC
Actuator or
Electric Heat
Supplemental Heat Loop
Suppl Htg
PI with
PRAC
Actuator or
Electric Heat
PI Loops Coordinated via
VAV Box Mode
(Finite State Machine)
control2
Figure 4: Control Diagram
22
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Because the supply air is cool, the zone airflow increases when the
zone temperature is above setpoint, and decreases when the zone
temperature is below setpoint. To satisfy ventilation requirements,
there is usually a minimum supply airflow.
For exterior zones, reheat coils are commonly installed at the VAV
box. If the VAV box is at its minimum flow and additional heat is
required to maintain the zone setpoint, a reheat coil is used. This is
accomplished via the actuator or electric heat control logic shown in
Figure 4. Additional supplemental heat (baseboard radiation) may also
be sequenced.
Note:
In this document, supplemental heat refers to heating devices
not in the airstream of the VAV box (for example, baseboard and
radiant panels).
For more details about the PID, PRAC, and P-Adaptive, see the
Control Loops topic in the Theory of Operation section.
Supply Exhaust Option for Single Duct Applications
Some zones require flow control of both the supply and exhaust flow
to prevent infiltration of contaminants into the zone (using positive
pressure) or to prevent the contents of the zone from passing to
surrounding zones (using negative pressure). The VMA Supply
Exhaust application uses a flow differential to set the relationship
between the supply and exhaust control loops. The exhaust setpoint
tracks the sum of the supply flow setpoint and the current differential
setpoint. For example, a flow differential less than zero provides a
positive pressure.
The exhaust flow controller is active during all modes of control,
including the command modes (Shutdown Open, Shutdown Closed,
Low Limit). The exhaust setpoint continues to track the sum of the
supply flow setpoint and the current differential setpoint. During
Shutdown Closed or Low Limit, the supply setpoint is commanded to
zero. Therefore, a positive differential (negative pressure) can be
maintained during these modes if the exhaust fan remains running.
A negative differential (positive pressure) requires supply flow and
cannot be maintained during Shutdown Closed or Low Limit.
The VMA integrated actuator has a stroke time of 30 seconds for
90 degrees of travel. The stroke time for actual degrees of travel is
calculated automatically by the application during the first
autocalibration after restart. The stroke time for external actuators
must be configured manually.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
23
For floating/3-wire external actuators (position adjust output), the
stroke time is an attribute of the output object and can be modified by
double-clicking on the output in the Outputs screen in HVAC PRO
software. For proportional external actuators (analog output), the
stroke time is an attribute of the application and can be modified in the
Parameters screen in HVAC PRO software under the corresponding
Damper Actuator group (Supply or Exhaust).
The actual stroke time for the full-stroke rotation of the actuator
should be the value configured for these outputs. The VMA supply
exhaust application automatically compensates for actuators with
different stroke times. If the stroke time of the supply damper actuator
and the exhaust damper actuator are not equal, the application limits
the rate at which the flow setpoints change to allow the controller to
maintain the differential setpoint at all times.
VAV Box Mode for Single Duct Applications
The VAV Box mode determines which PID control loops are active,
and controls VMA supervisory Command modes. Figure 5 shows the
state diagram for the VAV Box mode. Within VAV Box mode are two
main super-states: Command modes and Auto modes. The Command
modes include Shutdown Open, Shutdown Closed, Warmup, Water
System Flush, and Low Limit (Table 5).
24
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Table 5: Command Modes
Mode
Description
Shutdown
Open/Closed
Two shutdown options are available: Shutdown Open and Shutdown Closed. The VAV Box
mode present value must be overridden to enter these states. The damper is commanded
open during Shutdown Open mode to satisfy the occupied cooling maximum flow setpoint.
During the Shutdown Closed mode, the damper position is 0% open. When either Shutdown
mode is activated, all the analog and binary outputs are turned off, and the PID control
loops are overridden to eliminate integration windup.
If supply fans are off and no temperature control is required, it is best to use Shutdown
Closed mode instead of de-energizing the Occupied mode during the unoccupied period.
Warmup
The Warmup mode assumes that warm air is being supplied by the air handling system to
bring the space to normal occupied operating temperature. It is also referred to as central
system warmup. During this mode, the VMA reverses its control action, with respect to the
primary airflow setpoint, to control the zone temperature while the unit is supplying warm air.
The Warmup mode uses the Cooling PID to modulate between the warmup minimum flow
and the cooling maximum flow. Supplemental heating, if available, also is enabled during
warmup. The Supplemental Heating PID controls simultaneously with the Cooling PID
during Warmup mode to satisfy the actual heating setpoint.
The user can choose to provide the supply temperature via network or Analog Input (AI).
When the supply temperature is greater than the actual cooling setpoint by a fixed amount
(the warmup differential), the present value transitions to Warmup and initiates the mode.
Note:
If the supply air temperature is measured locally with an AI, the sensor must be
mounted upstream of any heating coils in the VAV box.
Water System
Flush
This feature is typically used during the startup and commissioning of VMAs on a new job
site for the flushing and balancing of building heating water systems. During this mode, the
flow rate is modulated to maintain the cooling setpoint. The VAV Box mode present value
can be commanded into this mode by setting the Water System Flush parameter
(Command modes/Parameters window) equal to True. This feature affects incremental,
proportional, and two-position normally open and normally closed box and supplemental
heating outputs. This feature is not activated for devices configured with staged electric heat
or for box heating AO or DAO outputs if Box Htg Elec Protect is True.
Low Limit
The Low Limit mode is typically used for applications serving zones with direct openings
outside the building, including loading docks and offices with operable windows. During Low
Limit mode, the box heating device is off, and the damper is closed. If the zone temperature
drops below the low limit temperature setpoint, the supplemental heat is modulated to
control zone temperature. This mode is activated by the low limit contact or by user override
of the VAV Box mode.
If supply fans are off, but heating is required via supplemental heating devices, it is best to
use Low Limit mode instead of de-energizing the Occupied mode during the unoccupied
period. For these cases, the low limit temperature setpoint should be set to the desired night
setback temperature. If box heating is required during the unoccupied period, the supply
fans should be turned on and the Occupancy mode set to Unoccupied.
The automatic control modes of the VMA are Cooling, Satisfied, and
Heating (if present). The VMA automatically selects the mode
required to heat or cool the space, as necessary. If the configuration of
the controller is cooling only, or if the Heating Available parameter
(Commissioning view) is false, then the state machine does not
transition into heating. The Heating Available flag can be used to
prevent the Heating modes from being entered when heating devices
are physically present but currently unavailable (for example, the
boiler is shut off for the summer).
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
25
When the present value of VAV Box mode is equal to Heating, the
operation of the VMA is determined by the present value of the
Heating mode state machine. Figure 6 shows the logic of the Heating
mode on a separate state.
VAV Box Mode
Command Modes
3
1
Shutdown
Open
0
Shutdown
Closed
No Overrides
Water
System
Flush
2
Warmup
4
Low Limit
Supply Air Temperature >
Zone Temperature
Warmup Differential
Water System
Flush = True
Low Limit
Contact = Active
Auto Modes
7
Zone Temperature < Htg Setpoint and
Htg Available = True and
Htg Config < > “Cooling Only”
Heating
6
Zone Temp Ctg > Setpoint
and ClgMaxFlow > ClgMinFlow
Cooling
Heating Available = False
ClgMaxFlow < ClgMinFlow
5
Satisfied
Heating Mode = “No Htg Required”
and Zone Temp > Htg Setpoint
Cooling PID
Saturation Status = Low
and Zone Temp < Clg Setpoint
SD-VAV_Box_Mode
Figure 5: VMA Single Duct VAV Box Mode State Diagram
26
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Heating Mode
0
No
Heating
Required
VAV Box Mode =
“Heating” and
Zone Temp < HSP
VAV Box Mode < > “Heating”
Box Heating PID
Saturation Status = Low
Supplemental Heating PID
Saturation Status = Low
6
Heating Configuration =
“Supplemental First”
or
“Supplemental Only”
Heating
Entry
State
Heating Configuration =
“Box First” or
“Box Only”
Heating Control Modes
3
1
Box
Heating
Box Heating PID
Saturation Status = High and
Heating Flow Reset = True
and Heating Configuration =
“Box Only”
Supplemental Heating PID
Saturation Status = High
and Heating Configuration =
“Supplemental First”
Supplemental Heating
PID Saturation Status = Low
Box Heating PID
Saturation Status = High
and Heating Configuration =
“Box First”
2
Supplemental
Heating with
Full Box
Heating
Supplemental
Heating
Box Heating PID
Saturation Status = Low
Heating Flow PID
Saturation Status = Low
and Heating Configuration =
“Box Only”
Supplemental Heating PID
Saturation Status = High and
Heating Flow Reset = True
Heating Flow PID
Saturation Status = Low and
Heating Configuration = “Box First”
5
Maximum
Heating with
Flow Reset
Heating Flow PID
Saturation Status = Low
and Heating Configuration =
“Supplemental First”
4
Box Heating
with Full
Supplemental
Heating
Box Heating PID
Saturation Status = High and
Heating Flow Reset = True
SD-Heating_Mode
Figure 6: Heating Mode State Diagram
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
27
VMA Single Duct Parameters
The VMA has adjustable parameters, but most do not require changes.
Changing parameters incorrectly may cause the controller to
malfunction.
The Attributes and Parameters section describes all of the parameters
shown in the main views as well as most of the attributes of the input
and output sections.
If you are changing the flow units from the default created by
HVAC PRO software, verify the Delta P sensor is still set up properly.
If the setup attribute is changed, HVAC PRO software updates the Min
Value, Max Value, and Units attributes based on the range chosen.
HVAC PRO Release 7.00 and 7.01 set the Min Value to 0.0. The Min
Value should be -24.9 Pa (-0.1 inches w.c.). HVAC PRO Release 7.02
and later sets this attribute to the correct value.
VMA Dual Duct Applications
Control Overview
Figure 7 shows the overall control diagram for the basic dual duct
application. As with the single duct application, the dual duct
application uses cascaded control loops to achieve pressure
independent control. The primary control loop uses a PID tuned by
PRAC that produces an output with units of heat transfer rate. This
PID is termed Energy Balance PID, because the output indicates the
current heat transfer referenced to an energy balance on the zone.
The heat transfer specified by the Energy Balance PID is used to
calculate flow setpoints for the hot and cold decks. Individual flow
control loops using the P-Adaptive flow controller command the hot
and cold deck damper actuators to achieve the flow setpoints.
The supplemental heating output (if available) is controlled by a
separate PID (tuned by PRAC for AO and PAO output types). The
Energy Balance PID and Supplemental Heating PID are coordinated
by the VAV Box mode finite state machine. For more details about the
PID and PRAC, see the Control Loops topic in the Theory of
Operation section earlier in this document.
28
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Energy Balance Loop
PI Loops Coordinated
via VAV Box Mode
(Finite State Machine)
CONVERT
Energy
Balance PI
with PRAC
CD
Setpt
Heat Transfer
Rate to
Flow Setpoints
Flow Control
Loops
HD
Setpt
(P-Adaptive)
Working
Setpoint
Supplemental Heat Loop
Suppl Htg
PI with
PRAC
Room
Actuator or
Electric Heat
Room Loop
Temperature
Transmitter
DD-Overview
Figure 7: Basic Control Diagram for the VMA Dual Duct Application
Heat Transfer to Flow Setpoint Conversion for VMA Dual Duct Applications
The heat transfer rate specified by the Energy Balance PID is
converted to hot and cold deck flow setpoints based on a heat transfer
model of the dual duct box and an energy balance analysis on the zone.
For steady state conditions with the zone temperature near setpoint, the
heat transfer to the zone can be calculated using the following formula:
Q zone = Qconvert* [WCD * (TCD Tzone,SP) + WHD* (THD Tzone,SP)]
In this equation, WCD and WHD are the cold and hot deck volume flow
rates. By this definition, the heat transfer is positive when the zone is
being heated and negative when the zone is being cooled. The term
Qconvert is dependent on the flow and temperature measurement units
and is used to convert the product of flow and temperature difference
to heat transfer. Table 6 shows the values required for Qconvert.
Table 6: Heat Transfer Conversion Factor
Flow Units
Temperature Units
Q Convert
cfm
°F
1.08
3
M /hr
°C
1.1435
l/s
°C
4.119
cfm
°C
1.944
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
29
The heat transfer conversion requires a number of steps and various
pieces of information. Figure 8 shows a data and calculation flow
chart.
Flow Setpoint
Determine
Configuration
Flow Setpoint
Profile
Occupancy
Mode
Calculate Zone
Temp Setpoint
Temperature
Configuration
Setpoints
VAV Box Mode
FSM
HD Flow
Discharge Air
Temperature
Estimate
CD Temp
Current Deck
Temperatures
HD Temp
CD Flow
CD Flow
Heat
Calculate
Transfer
Flow
Rate
Setpoints
Setpoint
HD Flow
Setpoint
conversion
Figure 8: Conversion from Heat Transfer Rate to Flow Setpoints
The flow setpoint and temperature setpoint configurations are
specified by the user for the Occupied and Unoccupied Occupancy
modes. The current flow profile is calculated based on the active
Occupancy mode. Depending on the flow profile, one of
two temperature setpoint calculation methods is used to determine the
cooling and heating temperature setpoints. The hot and cold deck
temperatures are either estimated online by the controller based on the
discharge air temperature or specified by the user. The flow setpoints
are then calculated for each deck. Most of the elements shown in
Figure 8 that are used in the flow setpoint calculation are described
individually later in this section. The Occupancy mode calculation, as
well as the basics of the temperature setpoint calculation, were
previously described in this section.
30
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Flow Control Loops
Figure 9 shows the flow control loops for the default dual duct
application. If one of the velocity pressure (flow pickup) sensors is
located on the mixed air duct, the total flow controller commands the
damper actuator of the unmeasured flow based on maintaining the total
flow setpoint. For more information on the P-Adaptive flow control
algorithm, see the Control Loops topic in the Theory of Operation
section.
CD Flow
Flow
Calculation
dP Sensor
CD dP
CD Flow
CD
CD Actuator
Setpoint
P-Adaptive
Command
HD Flow
HD
HD Actuator
Setpoint
P-Adaptive
Command
Dual Duct
Mixed Air
VAV Box
to Zone
HD dP
HD Flow
Flow
Calculation
dP Sensor
controlloops
Figure 9: Flow Control Loops for the VMA Dual Duct Application
Flow Setpoint Configuration for VMA Dual Duct
Applications
The general flow schedule for the Dual Duct application is defined
using a set of basic configuration parameters. The internal parameters
used to calculate the actual operating flow setpoints, however, vary
depending on the values of several Boolean flags that designate special
conditions and the specifications of Indoor Air Quality (IAQ)
ventilation requirements.
Basic Flow Setpoint Parameters
The flow setpoint schedule for the VMA dual duct application is
described by five basic configuration parameters:
1. Cooling Maximum Flow
2. Heating Maximum Flow
3. Box Minimum Flow (Occupied and Unoccupied)
4. Cold Deck Minimum Flow (Occupied and Unoccupied)
5. Hot Deck Minimum Flow (Occupied and Unoccupied)
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
31
The maximum flow setpoints specify the total flow for the VAV Box
and do not vary with occupancy. The minimum flow setpoints are
specified separately for the Occupied and Unoccupied Occupancy
modes. The unoccupied flow setpoints are used when the Occupancy
mode is either Standby or Unoccupied. Depending on the values of
these five parameters, the flow schedule takes one of three basic
forms: constant volume, variable volume with mixing (or blending),
and variable volume without mixing.
To specify a constant volume flow schedule, the flow setpoints should
be equal for the Cooling Maximum Flow, Heating Maximum Flow,
and Box Minimum Flow. The sum of the Cold and Hot Deck Min
Flow setpoints should be less than this maximum flow. Figure 10
shows an example of a flow schedule. Table 7 shows the flow
setpoints for each of the example profiles.
Note:
In Figures 10-12, the horizontal axis represents the range of
output of the controller (between full heating at one end of the axis and
full cooling at the other). Because PI Control is used, this axis does not
have any direct correlation to temperature or proportional bands. The
control range indices are used to allow simple representation of the
flow setpoint configuration profile.
1000
1000
Total Flow SP
CD Flow SP
HD Flow SP
Box Min Flow
Cooling Maximum Flow
Box Min Flow
Heating Maximum Flow
Flow
Setpoint
500
500
Cold Deck Min Flow
Hot Deck Min Flow
0
0
1
2
3
Control Range
Figure 10: Example Constant Volume Profile
4
constant
32
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
To specify a pressure independent flow schedule, the Box Minimum
Flow should be less than the maximum flow setpoints for heating and
cooling. The term mixing refers to simultaneous modulation of the
cold and hot deck flow setpoints between the Cooling and Heating
modes. For mixing to be enabled, the sum of the Cold and Hot Deck
Min Flow setpoints must be less than the Box Minimum Flow
setpoint. The consulting engineer sometimes specifies this type of flow
schedule with mixing. Figure 11 shows an example of a variable
volume flow schedule with mixing, and Figure 12 shows one without
mixing.
1000
1000
Total Flow SP
CD Flow SP
HD Flow SP
Box Min Flow
Flow
Setpoint
Cooling Maximum Flow
Heating
Maximum Flow
500
500
Box Min Flow
Hot Deck Min Flow
Cold Deck Min Flow
0
0
1
2
3
Control Range
Figure 11: Example Variable Volume Profile with Mixing
4
varwithmix
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
33
1000
1000
Total Flow SP
CD Flow SP
HD Flow SP
Box Min Flow
Cooling Maximum Flow
Flow
Setpoint
Heating
Maximum Flow
500
500
Box Min Flow
Hot Deck Min Flow
Cold Deck Min Flow
0
0
1
2
3
4
Control Range
varwithoutmix
Figure 12: Example Variable Volume Profile without Mixing
Table 7: Flow Setpoints for Example Profiles
Profile
Heating
Maximum
Cooling
Maximum
Box
Min Flow
Cold Deck
Min Flow
Hot Deck
Min Flow
Constant Volume
700
700
700
150
50
Variable Volume
with Mixing
600
700
200
100
50
Variable Volume
without Mixing
600
700
200
125
75
The basic flow setpoint configuration specified by the deck and total
minimum and maximum flow setpoints is modified depending upon
the availability of each deck, the status of the warmup, cooldown, and
low limit flags, the IAQ requirements, and the discharge air
temperature low limit.
Cold and Hot Deck Available
Two network variables are provided, called Cold Deck Available and
Hot Deck Available, for the user to indicate the operational status of a
particular deck. During the peak summer months, the hot deck may not
be required and its supply fan turned off. When this situation occurs,
the Hot Deck Available flag should be set to false. When a Deck
Available flag is set to false, the flow setpoint for that deck is set to
zero and the damper actuator is driven to the full closed end-stop.
When a single deck is available, the box minimum flow is set equal to
the minimum flow of the available deck. The maximum total flow
setpoint for the available deck is not affected.
34
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Warmup and Cooldown Modes
In many buildings, the AHU supply fans are shut off during
unoccupied periods. Prior to returning to occupancy, a warmup or
cooldown period may be required to bring the system to normal
occupied operating conditions. Two network variables are provided,
called Warmup Req and Cooldown Req, to indicate that these modes
are active.
During Warmup, the Hot Deck Min Flow is set equal to the Warmup
HD Min. The cold deck flow setpoint is set equal to a constant value
specified by the Warmup CD Flow. The energy balance PI adjusts the
hot deck flow setpoint to maintain the actual heating setpoint. If the
Warmup CD Flow is zero, the cold deck is treated as if the Cold Deck
Available flag were set to false (damper forced closed).
During Cooldown, the supplemental heat is disabled, the Cold Deck
Min Flow is set equal to the Cooldown CD Min. The hot deck flow
setpoint is set equal to a constant value specified by the Cooldown HD
Flow. The energy balance PI adjusts the cold deck flow setpoint to
maintain the actual cooling setpoint. If the Cooldown HD Flow is zero,
the hot deck is treated as if the Hot Deck Available flag were set to
false (damper forced closed).
Low Limit Mode
The Low Limit mode is designed for systems that have operating
windows or perhaps an outside door (such as a loading dock). To
maintain stability of building pressurization and AHU operation, the
supply air to these zones must be cut off when the window is opened.
A closure contact on the window is connected to a binary input on the
VMA. When the window is open (Binary Input [BI] is active), the cold
deck and the hot deck are treated as if the Cold Deck Available and
Hot Deck Available flags are both equal to false, forcing both dampers
to close. The heating temperature setpoint is reset to the Low Limit
Temp Setpt, which is defaulted to 4°C (40°F). The supplemental
heating, if available, maintains the zone temperature to this setpoint.
The lighting control is not affected.
A network variable is provided, called Low Limit Req, to allow the
user to activate the Low Limit mode without having a BI contact. The
user may choose to use Low Limit mode rather than Shutdown Closed
if supplemental heating is available and the zone requires heating
during Unoccupied periods. In this case, the Low Limit Temp Setpt
should be adjusted to be the desired night setback temperature.
If lighting is controlled by the VMA, it must be turned off separately
by changing the occupancy status to unoccupied.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
35
Discharge Air Temperature Low Limit
Some dual duct applications use Cold Air Distribution. In these
systems, the cold deck temperatures are colder than normal systems,
often below 7°C (45°F). To prevent cold drafts at the zone, a minimum
discharge air temperature can be specified using the Discharge Temp
Limit setpoint. If the cold deck temperature is below and the hot deck
temperature is above the Discharge Temp Limit, the percent hot deck
flow is adjusted to maintain the discharge air temperature at or above
the Discharge Temp Limit. The total flow setpoint is not affected.
Note:
This limits the maximum cooling potential for a box and
should be used only if specified by the consulting engineer.
Temperature Setpoint Configuration for VMA Dual Duct
Applications
The VMA dual duct application supports the same temperature
setpoint configuration options as the single duct application. These
options are described in the Temperature Setpoints portion of the
Application Logic topic earlier in this Key Concepts section. The
calculation of the actual cooling and heating setpoints, however,
depends on the active flow profile. For the variable volume without
mixing flow profile, the actual cooling and heating setpoints are
calculated separately using the formulas previously described in this
section.
As shown in Figures 10-12, when both the hot and cold deck vary
together (between control range 2-3), the dual duct application
calculates a single temperature setpoint. This condition is True for
both the constant volume (Figure 10) and variable volume with mixing
(Figure 11) flow profiles. The single setpoint is calculated using the
following formula.
Actual Cooling Setpoint = Common Setpoint + Remote Adjustment +
(Cooling Setpoint + Heating Setpoint) / 2.0 + Actual Heating Bias +
Actual Cooling Bias + Summer Compensation + Winter
Compensation
Actual Heating Setpoint = Actual Cooling Setpoint
Therefore, for night setback to be active, the flow setpoints must not
be configured to vary the flow between control range 2-3. The default
unoccupied minimum flow setpoints (including box minimum) are set
to zero so that the default application has separate heating and cooling
setpoints during Unoccupied and Standby modes.
36
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
VAV Box Mode for Dual Duct Applications
The VAV Box mode determines which PID control loop is active and
the control range across which the Energy Balance PID is spanned. It
also controls VMA supervisory Command modes. Within VAV Box
mode are two main super-states: Command modes and Auto modes.
The Command modes include Shutdown Open and Shutdown Closed.
Table 8: Command Modes
Mode
Description
Shutdown
Open/Closed
Two shutdown options are available: Shutdown Open and Shutdown Closed. The VAV Box
mode present value must be overridden to enter these states. For the dual duct application,
the hot and cold deck dampers are commanded open during Shutdown Open mode to
satisfy 50% of the maximum heating and cooling flow setpoints, respectively. During the
Shutdown Closed mode, the dampers are commanded fully closed. When either Shutdown
mode is activated, all the analog and binary outputs are turned off, and the PID control
loops are overridden to eliminate integration windup when the system is put back in control.
If supply fans are off and no temperature control is required, it is best to use one of the
Shutdown modes instead of de-energizing the Occupied mode during the unoccupied
period.
Warmup,
Cooldown,
Low Limit
Warmup, Cooldown, and Low Limit are not modes within the Dual Duct VAV Box mode.
Instead, these modes (activated by Boolean parameters) directly affect the flow setpoint
calculations as described in the previous section.
Water System
Flush
Water System Flush is not a mode within the Dual Duct VAV Box mode. Instead, this mode
(activated by a Boolean parameter) indicates to the controller that the supplemental heating
device is unavailable. Floating/3-wire, proportional, and 2-position normally open and
normally closed outputs are commanded to the Flush Position when Water System Flush is
active.
The VMA dual duct application has up to five automatic modes for
control: Satisfied, Mixing, Cooling, Heating, and Supplemental
Heating (Suppl Heating). Figure 13 shows the full state diagram for
the VAV Box mode. Each of the transition paths between the Auto
modes is designated by a letter and each path may have multiple
transition conditions. Figures 14 and 15 show specific transition
conditions for each configuration. Some transitions are used only when
the application configuration changes (for example, constant volume
during occupied and variable volume during unoccupied). Paths A-F in
Figure 13 are examples of transitions that occur in these instances.
For single duct applications, the Heating and Cooling modes are
fundamentally different processes because cooling involves
modulating the airflow while heating involves modulating a heating
device while maintaining a constant flow. Traditionally, dual duct
applications have approached the modes in a similar manner.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
37
For dual duct applications with a single temperature setpoint, however,
the Heating and Cooling modes involve the same fundamental process
of modulating airflow. Therefore, the VMA dual duct application
operates in a limited set of the Auto modes depending on the flow and
temperature setpoint configurations and the availability of
supplemental heating, as is shown in Table 9. In this table, the control
range index refers to the main break points as were shown in the
example flow configurations (see Figures 10-12).
Dual Duct - VAV Box Mode
Shutdown
Override Closed
Override Open
1
Open
0
Closed
No Overrides
Auto
C
3
Mixing
F
H
G
M
5
Heating
6
Suppl
Heating
D
A
E
B
N
L
K
P
O
J
2
Satisfied
4
Cooling
I
DD-VAV_Box_Mode
Figure 13: VMA Dual Duct VAV Box Mode State Diagram
38
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Table 9: Active Modes for Application Configurations
Zone
Temperature
Setpoints
Supplemental
Heating
Single
1 to 2
Control Range Index
2
2 to 3
3 to 4
N/A
Mixing
Mixing
Mixing
Mixing
Single
Available
Heating
Suppl Heating
Mixing
Mixing
Separate
N/A
Heating
Satisfied
Satisfied
Cooling
Separate
Available
Heating
Suppl Heating
Satisfied
Cooling
For configurations with a single temperature setpoint and no available
supplemental heat, the VMA dual duct application operates in a single
mode termed mixing. This includes applications that are required to
have a single setpoint (see temperature setpoint description), as well as
applications that have a single setpoint because the heating and cooling
biases are set to zero.
For applications with supplemental heating available, the supplemental
heating device is modulated before the hot deck flow is increased
(corresponding to control index 2). Figure 14 shows the active Auto
modes and transitions for this configuration.
Auto - Single Zone Temperature Setpoint
G
Energy Balance PID Saturation = High
H
Suppl Heating PID Saturation = Low
M
Suppl Heating PID Saturation = High
and HD Heating Max > HD Heating Min
3
Mixing
N
Energy Balance PID Saturation = Low
and Suppl Heating Available = True
M
5
Heating
N
H
G
6
Suppl
Heating
singlezone
Figure 14: Auto Modes with Single Zone Temperature Setpoint
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
39
For configurations with separate heating and cooling setpoints, the
control range is divided into Heating, Cooling, and Satisfied modes.
The Supplemental Heating mode is also active if supplemental heating
is available. Figure 15 shows the active Auto modes and transitions for
these configurations. The application controls to the cooling setpoint in
the Cooling mode and the heating setpoint in the Heating and
Supplemental Heating modes. In the Satisfied mode, the flow setpoints
are maintained at the minimum values until the zone temperature goes
above or below the cooling or heating setpoint, respectively.
Note:
In order for a VMA application to operate with dual
setpoints, the flow configuration must have constant flow setpoints
between control index 2-3. This requires the box minimum flow to be
equal to the sum of the cold and hot deck minimum flows.
Auto - Separate Heating and Cooling Zone Temperature Setpoints
I
CD Cooling Max > CD Cooling Min
and Zone Temp > Cooling Setpoint
M
Suppl Heating PID Saturation = High
and HD Heating Max > HD Heating Min
J
Energy Balance PID Saturation = High
and Zone Temp < Cooling Setpoint
N
Energy Balance PID Saturation = Low
and Suppl Heating Available = True
K
Zone Temp < Heating Setpoint
and Suppl Heating Available = True
O
Zone Temp < Heating Setpoint
and HD Heating Max > HD Heating Min
and Suppl Heating Available = False
L
Suppl Heating PID Saturation = Low
and Zone Temp > Heating Setpoint
P
Energy Balance PID Saturation = Low
and Zone Temp > Heating Setpoint
and Suppl Heating Available = False
M
5
Heating
6
Suppl
Heating
N
L
K
P
O
J
4
Cooling
2
Satisfied
I
separatezone
Figure 15: Auto Modes with Separate Zone Temperature Setpoints
Deck Temperatures for VMA Dual Duct Applications
The dual duct application uses the hot deck and cold deck air
temperatures to translate the heat transfer output from the Energy
Balance PID to individual flow setpoints for the hot and cold decks.
The application supports two methods for specifying the deck
temperatures.
40
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
If a discharge air temperature sensor is not installed, two network
variables are provided, named Cold Deck Air Temp and Hot Deck Air
Temp. These variables are configurable and can be set in the
application to match an average value for the AHU deck temperature
setpoint. They are also included in the mapping group and can be
updated via network overrides to match the current sensed
temperatures at the AHU. If a discharge air sensor is installed, the deck
temperatures are estimated online by the controller.
When the deck temperatures are updated either via the network
variables or via online estimation, the VMA dual duct application
becomes a “deck temperature independent” controller in addition to
being pressure independent. Normally, if the deck temperature were to
change, the controller would be able to react only after the zone
temperature was affected. With the knowledge of the deck
temperatures, the controller reacts to prevent these changes from
affecting the zone temperature.
Deck Temperature Estimation
The dual duct application uses recursive parameter estimation to
determine the hot and cold deck temperatures from the mixed air
temperature, hot deck flow rate, and cold deck flow rate. When the
flow velocity at both sensors is sufficient to ensure accurate
measurements, a Recursive Least-Squares (RLS) method is used. The
minimum velocity is configured using the Min_dP_Velocity
parameter. When one of the flows is below the minimum velocity, that
deck temperature is held constant while the other temperature is
updated using an exponentially weighted moving average.
The RLS method chosen combines covariance resetting, exponential
forgetting, and conditional updating. Exponential forgetting allows the
recursive parameter estimation to track slowly varying processes. In
some dual-duct VAV boxes, the hot or cold deck temperatures may
change abruptly. Covariance resetting allows the parameter estimation
algorithm to track abrupt changes. Simulation studies were performed
to determine an appropriate threshold for resetting the covariance
matrix. Also, simulation studies were used to determine an initial value
for the covariance matrix. Conditional updating prevents the recursive
parameter estimation from becoming numerically unstable.
To obtain further information on this topic:
Lung, Lennart, and Torsten Soderström, c., 1983. Theory and Practice
of Recursive Identification, The MIT Press, Cambridge,
Massachusetts.
Åström, Karl Johan, and Bjorn Wittenmärk, c., 1995. Adaptive
Control, Second Edition, Addison-Wesley Publishing Company.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
41
VMA Dual Duct Parameters
The VMA has adjustable parameters, but most do not require changes
from the default. Changing parameters incorrectly may cause the
controller to malfunction.
The Attributes and Parameters section describes the parameters shown
in the main views and most of the attributes of the input and output
options.
VMA Diagnostics
Data Analysis and Compression
The VMA has the ability to collect data about its inputs, outputs, and
internally calculated variables. Inside the VMA, Exponentially
Weighted Moving Averages (EWMA) minimize memory
requirements, reduce communication traffic, and provide an easy way
to analyze collected data.
The most common method for representing a large amount of data
with a single variable estimate is to calculate the mean (or average) of
the data. Means are also useful because they smooth out random data
fluctuations. When collecting data over a long period of time, it is
desirable to give a higher weighting (level of importance) to the most
recent data, since it represents current conditions more accurately than
old data. An EWMA provides both of these characteristics. The
general form used in the VMA is given below:
(
(
(
X k = X k-1 + λ (X k X k-1)
where:
(
Xk
= estimate of variable X at the current sample, k
(
X k-1 = the past estimate of X at sample, k-1
λ
= is the forgetting factor or exponential smoothing constant,
0<λ<1.
The value for λ is automatically computed, based on the type of data
collected.
The VMA calculates four to eight EWMAs from the following
input value categories:
1. absolute value of airflow setpoint minus airflow (for supply,
exhaust, differential, and for each deck, if applicable)
2. absolute value of zone temperature setpoint minus zone
temperature
3. airflow setpoint minus airflow (for supply, exhaust, differential,
and for each deck, if applicable)
42
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
4. zone temperature setpoint minus zone temperature
The zone temperature and flow EWMA diagnostics turn off if any
required analog inputs are unreliable, or if the mode is Shutdown Open
or Closed. This prevents the diagnostics from becoming biased by
non-representative data.
EWMAs from the third and fourth inputs in the list above can have
either a positive or negative value:
•
A negative value indicates either a warm zone or a flow higher
than setpoint.
•
A positive value indicates either a cool zone or a flow lower than
setpoint.
The EWMAs can be used to detect faults within the VMA. For
example, if the EWMA of absolute temperature error is large, the box
may have a stuck heating valve or a blocked supply duct. EWMAs
from several VAV boxes can be compared, using HVAC PRO
software to easily identify boxes with poor relative performance.
Starved Box
The Starved Box diagnostic feature indicates when the VAV damper is
open to 100% in the Occupied mode for 10 minutes. For single duct
supply/exhaust applications, the starved status of both the supply and
exhaust are calculated independently. For the dual duct application, the
starved status of each deck is calculated separately (Starved Cold Deck
and Starved Hot Deck). This point can be trended and viewed to
diagnose a potential problem before the zone occupants complain of
discomfort. If the output of the damper command is set to 100% for
10 minutes, the starved box saturation flag is on. Once the damper
command drops below 100%, the flag is off.
When the Starved Box flag is True, the PRAC adaptive tuner is
disabled for PIDs that require flow to maintain control of the zone.
This means that in single duct applications, the Cooling PID is
disabled if Starved Box is True. Similarly, the Box Heating PID for
single duct applications is disabled if Starved Box is True and there is
no box fan active. In dual duct applications, the Energy Balance PID is
disabled if either Starved Cold Deck or Starved Hot Deck is true.
If the flag is on for an extensive period of time, use the following steps
to diagnose the problem:
1.
Check the static pressure near the box inlet to ensure that enough
air is being delivered to the zone to meet maximum flow
requirements.
2.
Verify the VMA design flow setpoints are correct.
3.
Check the damper linkage to ensure that the box is fully open.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
4.
43
Verify that the supply air temperature at the box inlet is correct.
Inadequate Cooling and Heating
The inadequate cooling and inadequate heating flags provide
diagnostics that indicate whether the cooling or heating commands
have saturated at 100% in an attempt to meet the current setpoint.
For the single duct application, inadequate cooling is True if the
Occupancy mode is occupied, the VAV Box mode is cooling, and the
Cooling PID is saturated high. However, if the zone temperature is
unreliable or starved box is True, the inadequate cooling flag
maintains its prior value. Inadequate heating is True if the Occupancy
mode is occupied and the PID controlling the final heating stage
saturates high. If the zone temperature is unreliable, the inadequate
heating flag maintains its prior value.
For the dual duct application, inadequate cooling is True if the
Occupancy mode is occupied, the VAV Box mode is cooling or
mixing, and the Heat Balance PID is saturated at full cooling. If the
zone temperature is unreliable or the cold deck is starved, the
inadequate cooling flag maintains its prior value. Inadequate heating is
True if the Occupancy mode is occupied, the VAV Box mode is
heating or mixing, and the Heat Balance PID is saturated at full
heating. If the zone temperature is unreliable or the hot deck is starved,
the inadequate heating flag maintains its prior value.
Actuator Stall
On the VMA1410/1420, feedback to the microprocessor indicates
when the integral stepper motor has stalled. The calculated damper
position can be viewed in the SMO attribute list as Damper Output.
If the stall is greater than 5% from the estimated stall position, the
Reliability attribute indicates Stalled during Positioning.
Actuator Duty Cycle
The actuator duty cycle is an indicator of damper actuator usage. This
diagnostic consists of controller runtime and actuator runtime. The
controller runtime is the total amount of time the controller has been
running since the application was downloaded. The actuator runtime is
the total amount of time the damper motor has been pulsed to drive the
actuator open or closed since the application was downloaded. These
runtimes are continually updated and saved to permanent memory
once per day. The actuator duty cycle is calculated as follows:
ActuatorDutyCycle =
ActuatorRuntime
*100%
ControllerRuntime
44
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Moving Average Actuator Diagnostics
Two additional actuator diagnostics were added for the single duct
application, starting with HVAC PRO Release 7.02. These diagnostics
are also calculated for both actuators in the dual duct application and
for the exhaust actuator if present.
The actuator diagnostics calculated include the moving average of the
actuator duty cycle and hourly reversal rate. This moving average uses
three samples weighted equally in the calculation and updated every
8 hours. The value of the moving average duty cycle indicates the
average percent runtime for that actuator during the past 24 hours. The
moving average reversal count indicates the average number of
actuator reversals each hour during the past 24 hours. These
diagnostics are calculated as follows:
MovAvgDutyCycle =
DeltaRuntime
*100.0
24.0
MovAvgReversals =
DeltaReversals
24.0
Note:
The actuator runtime for the proportional damper actuator is
estimated based on the stroke time parameter and the integrated
changes of command. This estimate will be inaccurate if the stroke
time parameter is incorrect or if the damper command is overridden
without allowing the actuator to remain in sync. This potential
inaccuracy affects both the moving average duty cycle diagnostics as
well as the single duct actuator duty cycle.
Flow Test
A flow profile is performed for the single duct applications (without an
exhaust box) at one or more VAV boxes using the VAV Box Flow
Test function in HVAC PRO software. This test provides an automatic
means of obtaining a damper position vs. flow plot. To quickly check
if damper direction is correct, use Step Amount % = 50% and Settle
Time (0-60 s) = 15 s. The flow should increase for 0-100%.
For additional information, refer to the HVAC PRO User’s Guide.
Data Graphing
Data graphing allows you to graph up to three analog values in real
time. The data graphing feature is available under the Commission
menu in HVAC PRO software. Refer to the HVAC PRO User’s Guide
for further explanation of this feature.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
45
Detailed Procedures
Creating a VMA Single Duct Application
To create a VMA single duct application:
1. On the Options menu, click Job Information.
2. Select either English or Metric units. Click OK.
3. On the File menu, click New.
4. In the Application Group drop-down list, click VAV Applications.
5. In the Application box, click VMA Single Duct.
Note:
Refer to the HVAC PRO User’s Guide for further
explanation.
6. Answer the questions as they are presented. The sequence of
questions and answers appears in Figures 16-19. An explanation of
each question and answer appears following the figure in which the
question is shown. The chosen answer for each question provides
default parameter values. The user changes those values, when
required.
1 Select the single duct VAV box control strategy:
Q1
1 Pressure independent
2 Press Indep w BO for autocal solenoid(s)
Q2
2 Actuator for the VAV box damper:
1 VMA integrated actuator
2 Position Adjust Output (floating/3-wire)
Q3
A1
3 Analog Output (proportional)
A2-5
3 Fan type and output type:
1 No fan
Q4
2 Series fan - BO
3 Series fan - AO
4 Parallel fan - BO - temperature based
5 Parallel fan - BO - flow based
Continued at
Question 5
4 Exhaust Box actuator type:
1 No exhaust box
2 Position Adjust Output (floating/3-wire)
3 Analog Output (proportional)
sd_q1-4
Figure 16: VMA Single Duct Basic Box Configuration Questions
46
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Select the Single Duct VAV Box Control Strategy
Choose from the options in Table 10.
Table 10: Select the Single Duct VAV Box Control Strategy
Option
Description
Pressure
Independent
A pressure independent application controls the VAV box
supply flow, independent of the supply duct static pressure
variations. The controller uses a P-adaptive control
algorithm, along with a flow sensor, to modulate the supply
damper to maintain the required flow setpoint. For further
explanation of the point configuration, refer to the
Variable Air Volume Modular Assembly (VMA) 1400 Series
Overview and Engineering Guidelines Technical Bulletin
(LIT-6363120).
Press Indep w BO
for autocal
solenoid(s)
This option allows autocalibration using BO activated
solenoid air valve(s) that zeros the differential pressure
across the velocity pressure sensor(s). It allows
autocalibration to occur without closing the damper(s). For
more information, refer to the Autocalibration topic in the
Application Logic section of this document.
Actuator for the VAV Box Damper
Choose from the options in Table 11.
Table 11: Actuator for the VAV Box Damper
Option
Description
VMA Integrated
Actuator
The VMA1410/1420 assembly has an integral actuator
controlled by a Stepper Motor Object. For more information,
see the SMO description in the Input/Output Options topic in
the Attributes and Parameters section of this document.
Position Adjust
Output
(Floating/3-Wire)
and Analog
Output
(Proportional)
The VMA1430 does not have an integrated stepper motor
actuator. The VMA1420 and VMA1430 support an external,
floating/3-wire (incremental) or proportional actuator. A pair
of BOs or a single AO is used.
Fan Type and Output Type
A VAV box fan is installed either in series or in parallel with the box
damper. In parallel fan powered terminal boxes, the fan runs
intermittently to produce a flow of plenum air through the box,
whenever needed. This occurs even if the box damper is fully closed to
the primary air source. Series fans run continuously in the Occupied
mode to improve the comfort of occupants by maintaining a constant
airflow through the diffuser, providing a better mix of air regardless of
the position of the supply air damper.
Choose from the options in Table 12.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
47
Table 12: Fan Type and Output Type
Option
Description
No Fan
No points, parameters, or logic are assigned for this answer.
Series Fan - BO
The series fan remains off during Shutdown and Calibration
modes and runs continuously during Occupied and Standby
modes. During Unoccupied mode, the fan cycles on if
heating is required.
Prior to starting the fan, the damper is driven closed for the
fan start delay time plus the damper stroke time to ensure
that the fan is not rotating backwards. During warmup, the
series fan cycles on if heating is required. A single BO is
used.
Series Fan - AO
The series fan AO operates in the same manner as the BO
option. The series fan AO uses a single Analog Output (AO)
to provide a 0 to 10 VDC signal to a fan speed controller
(S66 speed controller). The fan is set to a constant speed
based on the Fan Speed Percent parameter. The fan
operates at this constant speed setting whenever it runs.
The VMA turns the fan off by setting this AO to 0 VDC.
Parallel Fan - BO Temperature
Based
When this option is selected, the parallel fan remains off
during Shutdown and Calibration modes and cycles on
whenever the Heating modes are active, regardless of
Occupancy mode. If box heating is not chosen for this box,
the temperature-based parallel fan is not turned on. A single
BO is used.
Parallel Fan - BO Flow Based
When this option is selected, the parallel fan remains off
during Shutdown and Calibration modes and cycles on
whenever the Heating modes are active during the
Unoccupied mode. In addition, the parallel fan is cycled on
during Standby and Occupied modes when the supply flow
is less than the parallel fan minimum flow. A single BO is
used.
48
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Exhaust Box Actuator Type
Choose from the options in Table 13.
Table 13: Exhaust Box Actuator Type
Option
Description
No Exhaust Box
No points, parameters, or logic are assigned for this answer.
Floating/3-Wire
(Incremental) and
Proportional
Actuator
The VMA1420/1430 support an external, floating/3-wire
(incremental) or proportional actuator. A pair of BOs or a
single AO is used. The VMA1430 does not have an
integrated stepper motor actuator.
The controller uses flow differential to set the relationship
between the supply and exhaust control loops. The exhaust
setpoint tracks the sum of the supply flow setpoint and the
current differential setpoint. A flow differential less than zero
provides a positive room pressure. You can select separate
occupied and unoccupied differential setpoints. This allows
you to change zone pressurization simply by changing
occupancy modes.
Note:
The exhaust flow controller is active during all
modes of control, including the command modes (Shutdown
Open, Shutdown Closed, Low Limit). The exhaust setpoint
continues to track the sum of the supply flow setpoint and
the current differential setpoint. During Shutdown Closed or
Low Limit, the supply setpoint is commanded to zero.
Therefore, a positive differential (negative pressure) can be
maintained during these modes if the exhaust fan remains
running. A negative differential (positive pressure) requires
supply flow and cannot be maintained during Shutdown
Closed or Low Limit.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
49
5 Heating configuration:
Q5
1 None (cooling only)
2 Box heating
3 Supplemental heating (basebrd, radiant)
4 Both box and supplemental heating
A1
A2
A3
A4
Q6
Q7
Q6
6 Box heating:
1 Position Adjust Output (floating/3-wire)
2 Analog Output (proportional)
3 Duration Adjust Output
4 Binary Output (normally open valve)
5 Binary Output (normally closed valve)
Q7
6 Electric 1-stage
7 Electric 2-stages
8 Electric 3-stages
Q8
7 Supplemental heating:
1 Position Adjust Output (floating/3-wire)
2 Analog Output (proportional)
Q9
Q9
3 Duration Adjust Output
4 Binary Output (normally open valve)
5 Binary Output (normally closed valve)
6 Electric 1-stage
8 Which heat goes on first:
1 Supplemental Heating
Continued at
2 Box Heating
Question 10
Skip if
fan powered
box
9 Increase box flow setpoint upon full heating?
1 No (recommended)
2 Yes
sd_q5-9
Figure 17: VMA Single Duct Heating Configuration Questions
Heating Configuration
Choose from the options in Table 14.
Table 14: Heating Configuration
Option
Description
None
(cooling only)
No points, parameters, or logic are assigned for this answer.
Box Heating
This answer assigns points, parameters, and logic to
support heating devices located at the VAV box.
Supplemental
Heating
(Baseboard,
Radiant)
Choosing this answer assigns points, parameters, and logic
to control supplemental heating sources (baseboard, or
radiant panels, for example.) These types of heat are not
dependent upon the supply airflow for proper operation.
Both Box and
Supplemental
Heating
This choice assigns points, parameters, and logic to control
both a box mounted heating device and supplemental
heating devices. The box and supplemental heating devices
operate in the order specified by the user.
50
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Box and Supplemental Heating
Choose from the options in Table 15.
Table 15: Box and Supplemental Heating
Option
Description
Position Adjust
Output
Analog Output
Duration Adjust
Output
These options load a Position Adjust Output, Analog Output,
or Duration Adjust Output respectively, to control the heating
device. Complete descriptions of these output types are
given in the Input/Output Options topic in the Attributes and
Parameters section of this document.
For Application Revision 5 and greater (HVAC PRO
software Release 8.03 and later), minimum flow protection is
available for box heating Analog Output and Duration Adjust
Output options. To activate this protection, configure the Box
Htg Elec Protect attribute as True. The minimum flow
protection operates in the same manner as described below
for the staged electric devices.
Binary Output
(Normally Open or
Normally Closed
Valve)
These options load a single binary output that is set up for a
maintained output. The polarity for the normally open valve
is Reverse, while the polarity for the normally closed valve is
Normal. When the command is greater than the make limit,
the BO present value is set to Active. When the command
drops below the make limit by the heating differential, the
BO present value is set to Inactive. The BO for the normally
open valve is energized when the present value is Inactive
(valve closed), and the BO for the normally closed valve is
energized when the present value is Active (valve open).
For more information, see the binary output description in
the Input/Output Options topic in the Attributes and
Parameters section of this document.
Electric 1-stage
Electric 2-stages
Electric 3-stages
The operation of the Electric Heat Sequencer output type is
described in the Input/Output Options topic in the Attributes
and Parameters section of this document. For box heating
devices using electric heat, the application contains logic to
avoid operating the electric heat with inadequate flow.
Operation with inadequate airflow could cause thermal
overload protection to trip. VAV box manufacturers typically
provide a pressure switch to lock out electric heat in the
absence of inlet static pressure. In pressure independent
boxes, electric heating is enabled when the measured flow
is greater than the box electric heating minimum flow
parameter or a box fan is operating. Below this value,
electric heat is disabled. To help prevent the box heating
from becoming disabled when at minimum flow, set the
Occupied Htg Flow and Unoccupied Htg Flow setpoints at
least 25% higher than the Box Elec Htg Min Flo parameter.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
51
Which Heat Goes on First
Choose from the options in Table 16.
Table 16: Which Heat Goes on First
Option
Description
Supplemental
Heat
Points, parameters, and logic are assigned to cause the
supplemental heating to be used prior to the box heating.
Box Heating
Points, parameters, and logic are assigned to cause the box
heating to be used prior to the supplemental heating.
Increase Box Flow Setpoint upon Full Heating
Choose from the options in Table 17.
Table 17: Increase Box Flow Setpoint upon Full Heating
Option
Description
No
(Recommended)
No points, parameters, or logic are assigned for this answer.
Yes
This answer assigns points, parameters, and logic to allow
the heating flow setpoint to increase after all types of
heating selected have reached their maximum value. In
certain situations, additional heating can be achieved by
allowing an increase in the airflow across the heating coil.
Utilizing this feature significantly increases energy costs
(due to reheating the cooler supply air) and is not
recommended.
10 Thermostat type:
Q10
1 No remote adjustment
2 Warmer/cooler adjust
A1-3
A4
3 Remote setpoint
4 TMZ Digital Room Sensor
5 R F Wireless No remote adjustment
6 R F Wireless Warmer/cooler adjust
7 R F Wireless Remote setpoint
Q11
Q12
Continued at
Question 13
Figure 18: VMA Single Duct Thermostat and Occupancy Input
Questions
52
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Thermostat Type
The temperature setpoint calculation is described in detail in the
Key Concepts section of this document. Choose from the options in
Table 18.
Table 18: Thermostat Type
Option
Description
No Remote
Adjustment
No remote setpoint adjustment is provided with this option.
Warmer/Cooler
Adjust
(±3°C, ±5°F)
This adds AI-2 with a default range of -3 to 3°C (-5 to 5°F).
This can be scaled by the user. The warmer/cooler
adjustment is active during all modes of operation
(Occupied, Unoccupied, and Standby).
Remote Setpoint
(12/28°C, 65/85°F)
This adds AI-2 with a default range of 12 to 28°C
(65 to 85°F). This can be scaled by the user. The
warmer/cooler adjustment is active during all modes of
operation (Occupied, Unoccupied, and Standby).
TMZ Digital Room
Sensor
This option adds the point, parameters, and logic to
interface with the TMZ Digital Room Sensor. The TMZ
includes an occupancy button that operates according to the
Occupied mode (timed) option. For more information, see
the Room Sensor with LCD Display (TMZ1600) Installation
Instructions (LIT-6363110).
RF Wireless –
No Remote
Adjustment
This option provides support for the TE-77xx Series RF
Wireless Thermostats with no remote setpoint adjustment.
RF Wireless –
Warmer/Cooler
Adjust
This option provides support for the TE-77xx Series RF
Wireless Thermostats that include a warmer/cooler setpoint.
This adjustment has a default range of -3 to 3°C (-5 to 5°F)
that can be scaled by the user. It is configured in the same
manner as the hardware option (adjust AI-2 attributes) and
is active in all modes of operation (Occupied, Unoccupied,
and Standby).
RF Wireless –
Remote Setpoint
This option provides support for the TE-77xx Series RF
Wireless Thermostats that include a remote setpoint. This
setpoint has a default range of 12 to 28°C (65 to 85°F) that
can be scaled by the user. It is configured in the same
manner as the hardware option (adjust AI-2 attributes) and
is active in all modes of operation (Occupied, Unoccupied,
and Standby).
Occupancy Button and Occupancy Sensor
The occupancy button and occupancy sensor options are described in
the Application Logic topic in the Key Concepts section of this
document. This section also shows the priority of the occupancy
button and sensor inputs in the Occupancy mode calculation.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Q13
13 Initiate warmup mode if supply air is much
warmer than zone temperature?
1 No
2 Supply air temp via a network variable
3 Supply air temp via a hardware input
Q14
14 Binary input for Low Limit mode?
1 No
2 Yes
Q15
15 Summer/winter compensation of zone setpt
based on outdoor air temp:
1 None
2 Outdoor air temp via a network variable
16 Lighting control:
Q16
1 No lighting control
2 Start-Stop Output (on BO, off BO)
3 Pulsed Binary Output (BO w/status BI)
17 Separate control loop:
Q17
1 None
2 Analog Input to Position Adjust Output
3 Analog Input to Analog Output
4 Analog Input to Duration Adjust Output
5 Analog Input to Binary Output N/O
6 Analog Input to Binary Output N/C
7 Analog Input to Electric 1-Stage
8 Analog Input to Electric 2-Stage
9 Analog Input to Electric 3-Stage
sd_q13-17
Figure 19: VMA Single Duct Additional Configuration Questions
53
54
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Initiate Warmup Mode if Supply Air is Much Warmer than
Zone Temperature
Choose from the options in Table 19.
Table 19: Initiate Warmup Mode if Supply Air is Much Warmer than
Zone Temperature
Option
Description
No
No points, parameters, or logic are assigned for this answer.
The Warmup mode for this application can be activated only
by a user override of the VAV Box mode.
Supply Air Temp
Via a Network
Variable
This option loads a network variable to allow a supervisory
system to provide the supply air temperature to the
controller. If this temperature is greater than the zone
temperature by the warmup differential, the Warmup mode
is automatically activated. When the supply air temperature
drops below the zone setpoint, the controller reverts to
normal operation.
Supply Air Temp
Via a Hardware
Input
This option loads an analog input to sense the supply air
temperature. If this temperature is greater than the zone
temperature by the warmup differential, the Warmup mode
is automatically activated. When the supply air temperature
drops below the zone setpoint, the controller reverts to
normal operation.
Note:
If the supply air temperature is measured locally
with an AI, the sensor must be mounted upstream of any
heating coils in the VAV box.
Binary Input for Low Limit Mode
Choose from the options in Table 20.
Table 20: Binary Input for Low Limit Mode
Option
Description
No
No points, parameters, or logic are assigned for this answer.
The Low Limit mode for this application can be activated
only by a user override of the VAV Box mode.
Yes
This choice assigns points, parameters, and logic to provide
a low limit operation of supplemental heating. When a binary
input, such as a window contact or overhead door switch,
indicates Low Limit mode, the VAV box damper closes and
all fans (if present) and box heating (if present) turn off. If
the zone temperature drops below the low limit setpoint, the
supplemental heat (if present) operates to maintain the zone
temperature.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
55
Summer/Winter Compensation of Zone Setpoint Based on
Outdoor Air Temperature
Choose from the options in Table 21.
Table 21: Summer/Winter Compensation of Zone Setpoint Based on
Outdoor Air Temperature
Option
Description
None
No points, parameters, or logic are assigned for this answer.
Outdoor Air Temp
Via a Network
Variable
Summer/winter compensation allows temperature setpoint
reset based on outdoor air temperature. The complete
temperature setpoint calculation, along with the contribution
of the summer and winter compensation, is described in
detail in the Key Concepts section.
Lighting Control
The lighting output turns the lights on when the controller is in the
Occupied mode. When the controller transitions to the Unoccupied or
Standby mode, the lights turn off for two seconds and then turn back
on (blink). After the Light Shutoff Delay (user configurable with
default of two minutes), the lights turn off completely. There are
two types of lighting relays, start-stop output and pulsed binary output.
Note that only three BOs are left on the VMA1430 for lights/heating,
for example, when an incremental damper actuator is used.
Choose from the options in Table 22.
Table 22: Lighting Control
Option
Description
No Lighting
Control
No points, parameters, or logic are assigned for this answer.
Start-Stop Output
(on BO, off BO)
Points, parameters, and logic are assigned to provide a
start-stop output to control a momentary lighting relay
(GE RR-7EZ 24 V relay). Two triac outputs are used. The
first (start) triac pulses on when lighting should be on and
the second (stop) triac pulses on when lighting should be
off.
Pulsed Binary
Output
(BO w/status BI)
This choice assigns points, parameters, and logic to control
a pulse type lighting relay. One triac output is used. This
relay type provides a feedback contact to indicate its output
status and receives a pulse to change the state of the output
(Touchplate/Microlite relay). The controller monitors the
status of the feedback contact and issues the pulse when
the requested command does not match the current relay
feedback.
56
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Separate Control Loop
This allows the user to add a single extra control loop to the controller.
The default sideloop input is AI-3, a 0/16.5 V input scalable by the
user. If temperature input is desired, the sideloop input can be moved
to AI-4. The signal from the analog input becomes the process variable
of a PID controller. For Position Adjust Output (PAO) and AO output
types, PRAC is used to automatically tune the PI controller. The
output of the PID provides the command to the output types that
require a 0 to 100% signal (PAO, AO, DAO, Electric Heat Sequencer
[EHS]). If the output type is the binary normally open or closed valve,
the controller uses the sideloop make limit and sideloop differential to
operate the valve. There are no point conditioning, interlocking, or
Occupied mode provisions in this loop. PRAC does not run with EHS,
DAO, or BOs. For more complete descriptions of the output types, see
the Input/Output Options topic in the Attributes and Parameters
section of this document.
Creating a VMA Dual Duct Application
To create a VMA dual duct application:
1. On the Action menu, click Job Information.
2. Select either English or Metric units. Click OK.
3. On the File menu, click New.
4. In the Application Group drop-down list, click VAV Applications.
5. In the Application box, click VMA Dual Duct.
Note:
Refer to the HVAC PRO User’s Guide for further
explanation.
6. Answer the questions as they are presented. The sequence of
question and answers appears in Figures 20-23. An explanation of
each question and answer appears following the figure in which the
question is shown. The chosen answer for each question provides
default parameter values. The user changes those values when
required.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
57
1 Select the dual duct VAV box control strategy:
Q1
1 Pressure independent - variable box flow
2 Pressure independent - constant box flow
2 Discharge air temperature sensor installed?
Q2
1 No
2 Yes
Q3
3 Cold deck actuator type:
1 VMA Integrated Actuator
2 Position Adjust Output (floating/3-wire)
3 Analog Output (proportional)
Q4
4 Hot deck actuator type:
1 Position Adjust Output (floating/3-wire)
Q5
2 Analog Output (proportional)
5 Flow sensor locations:
1 Hot and cold deck flow
Q6
2 Hot deck and total flow
3 Cold deck and total flow
Continued at
Question 8
6 Exhaust box:
1 No exhaust box
dd_q1-6
Figure 20: VMA Dual Duct Basic Box Configuration Questions
Select the Dual Duct VAV Box Control Strategy
The VMA dual duct application set includes only pressure independent
applications. Two sets of default flow setpoint configuration
parameters are provided, one for a VAV with mixing flow schedule
and one for a constant volume flow schedule. Regardless of the default
values chosen at this question, any flow setpoint configuration can be
specified by changing the flow setpoint configuration parameters. The
unoccupied minimum flow parameters have default values of zero for
both options.
Discharge Air Temperature Sensor Installed
If a discharge air sensor is present, the application uses the measured
discharge air temperature to estimate online the hot and cold deck
temperatures. If a sensor is not installed, you can configure and/or
command the hot and cold deck source temperature network variables
to reflect the actual deck temperatures. The discharge temp limit is
enabled whether or not a sensor is present, but the default for the limit
has a value of 0°C (32°F).
58
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Cold Deck Actuator Type
The VMA dual duct application supports three actuator types for the
cold deck actuator. The VMA1420 has an integrated actuator. This
actuator is a stepper motor that allows fast response with fine step
resolution. If the integrated actuator is used, it must control the cold
deck. Instead of the integrated actuator, a VMA1430 can be used with
an external 3-wire (floating) actuator or proportional (analog output)
actuator. For a more detailed description of the output types, see the
Input/Output Options topic in the Attributes and Parameters section of
this document.
Hot Deck Actuator Type
The VMA dual duct application supports an external 3-wire (floating)
actuator or proportional (analog output) actuator for the hot deck
damper. For a more detailed description of the output types, see the
Input/Output Options topic in the Attributes and Parameters section of
this document. An example wiring diagram for the external actuator
and velocity pressures sensor is given in Mounting and Wiring
Variable Air Volume Modular Assembly (VMA) 1400 Series
Controllers Technical Bulletin (LIT-6363125).
Flow Sensor Locations
The VAV box manufacturer can mount flow pickups on the hot and
cold deck inlets upstream of the dampers. A flow pickup can also
measure the total flow rate, but this must be installed by site personnel
5-10 duct diameters downstream of the mixing chamber to ensure a
reliable reading and should be positioned to represent the average flow
in the duct. Turbulence in the duct can cause airflow to shift.
The application allows the user to specify flow sensor inputs from any
two of these three possible locations.
Exhaust Box
The current release of the VMA dual duct application does not support
exhaust box control.
7 Supplemental heating output type:
Q7
1 No supplemental heating
2 Position Adjust Output (floating/3-wire)
3 Analog Output (proportional)
4 Duration Adjust Output
Continued at
5 Binary Output (normally open valve)
Question 8
6 Binary Output (normally closed valve)
7 Electric 1-stage
dd_q7
Figure 21: VMA Dual Duct Heating Configuration Question
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
59
Supplemental Heating Output Type
The supplemental heat (if present) is modulated before the hot deck.
Table 23: Supplemental Heating Output Type
Option
Description
No Supplemental
Heating
No supplemental heating is assigned.
Position Adjust
Output
Analog Output
Duration Adjust
Output
Electric - 1 Stage
These options load a Position Adjust Output, Analog Output,
Duration Adjust Output, or one-stage Electric Heat
Sequencer respectively, to control the heating device.
Complete descriptions of these output types are given in the
Input/Output Options topic in the Attributes and Parameters
section of this document.
Binary Output
(Normally Open
Valve)
Binary Output
(Normally Closed
Valve)
These options load a single binary output that is set up for a
maintained output. The polarity for the normally open valve
is Reverse, while the polarity for the normally closed valve is
Normal. When the command is greater than the make limit,
the BO present value is set to Active. When the command
drops below the make limit by the heating differential, the
BO present value is set to Inactive. The BO for the normally
open valve is energized when the present value is Inactive
(valve closed), and the BO for the normally closed valve is
energized when the present value is Active (valve open).
For more information, see the binary output description in
the Input/Output Options topic in the Attributes and
Parameters section of this document.
Q8
8
Thermostat type:
1 No remote adjustment
2 Warmer/cooler adjust
A1-3
A4
3 Remote setpoint
4 TMZ Digital Room Sensor
Q9
9
Button for occupancy mode,
and its action when pressed:
1 No occupancy button
2 Occupied mode (timed)
Q10
3 Next mode (timed): Unocc - Standby - Occ
10 Sensor for occupancy mode, and its action:
Continued at
Question 11
1 No occupancy sensor
2 Occupied mode when occupancy sensed
3 Occ button canceled when unocc sensed
dd_q8-10
Figure 22: VMA Dual Duct Thermostat and Occupancy Input Questions
60
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Thermostat Type
The temperature setpoint calculation for the dual duct application is
described in the Application Logic and VMA Dual Duct Applications
topics in the Key Concepts section of this document.
Choose from the options in Table 24.
Table 24: Thermostat Type
Option
Description
No Remote
Adjustment
No remote setpoint adjustment is provided with this option.
Warmer/Cooler
Adjust
(+/-3°C, +/-5°F)
This adds AI-2 with a default range of -3 to 3°C (-5 to 5°F).
This can be scaled by the user. The warmer/cooler
adjustment is active during all modes of operation
(Occupied, Unoccupied, and Standby).
Remote Setpoint
(12-28°C, 65-85°F)
This adds AI-2 with a default range of 12 to 28°C
(65 to 85°F). This can be scaled by the user. The
warmer/cooler adjustment is active during all modes of
operation (Occupied, Unoccupied, and Standby).
TMZ Digital Room
Sensor
This option adds the point, parameters, and logic to
interface with the TMZ Digital Room Sensor. The TMZ
includes an occupancy button that operates according to the
Occupied mode (timed) option. For more information, see
Room Sensor with LCD Display (TMZ1600) Installation
Instructions (LIT-6363110).
Occupancy Button and Occupancy Sensor
The occupancy button and occupancy sensor options (Question 9 and
Question 10 in Figure 22) are described in the Key Concepts section of
this document. This section also shows the priority of the occupancy
button and sensor inputs in the Occupancy mode calculation.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Q11
61
11 Binary input for Low Limit mode?
1 No
2 Yes
12 Summer/winter compensation of zone setpt
based on outdoor air temp:
Q12
1 None
2 Outdoor air temp via a network variable
13 Lighting control:
1 No lighting control
Q13
2 Start-Stop output (on BO, off BO)
3 Pulsed Binary Output (BO w/status BI)
14 Separate control loop:
1 None
Q14
2 Analog Input to Position Adjust Output
3 Analog Input to Analog Output
4 Analog Input to Duration Adjust Output
5 Analog Input to Binary Output N/O
6 Analog Input to Binary output N/C
7 Analog Input to Electric 1-Stage
8 Analog Input to Electric 2-Stage
9 Analog Input to Electric 3-Stage
dd_q11-14
Figure 23: VMA Dual Duct Additional Configuration Questions
Binary Input for Low Limit Mode
Choose from the options in Table 25.
Table 25: Binary Input for Low Limit Mode
Option
Description
No
No points, parameters, or logic are assigned for this answer.
The Low Limit mode for this application can be activated
only by a user override of the Low Limit Req parameter.
Yes
This choice assigns points, parameters, and logic to provide
a low limit operation of supplemental heating. When the
application enters Low Limit mode, both VAV box dampers
close. If the zone temperature drops below the low limit
setpoint, the supplemental heat (if present) operates to
maintain the zone temperature at this setpoint.
62
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Summer/Winter Compensation of Zone Setpoint Based on
Outdoor Air Temperature
Choose from the options in Table 26.
Table 26: Summer/Winter Compensation of Zone Setpoint Based on
Outdoor Air Temperature
Option
Description
None
No points, parameters, or logic are assigned for this answer.
Outdoor Air Temp
Via a Network
Variable
Summer/winter compensation allows temperature setpoint
reset based on outdoor air temperature. The complete
temperature setpoint calculation, along with the contribution
of the summer and winter compensation, is described in
detail in the Key Concepts section.
Lighting Control
The lighting output turns the lights on when the controller is in the
Occupied mode. When the controller transitions to the Unoccupied or
Standby mode, the lights turn off for two seconds and then turn back
on (blink). After the Light Shutoff Delay (user configurable with
default of two minutes), the lights turn off completely. There are
two types of lighting relays, start-stop output and pulsed binary output.
Note that only one BO is left on the VMA1430 for lights/heating when
two incremental damper actuators are used. Choose from the options
in Table 27.
Table 27: Lighting Control
Option
Description
No Lighting
Control
No points, parameters, or logic are assigned for this answer.
Start-Stop Output
(on BO, off BO)
Points, parameters, and logic are assigned to provide a
start-stop output to control a momentary lighting relay
(GE RR-7 relay). Two triac outputs are used. The first (start)
triac pulses on when lighting should be on and the second
(stop) triac pulses on when lighting should be off.
Pulsed Binary
Output
(BO w/status BI)
This choice assigns points, parameters, and logic to control
a pulse type lighting relay. This relay type provides a
feedback contact to indicate its output status and receives a
pulse to change the state of the output
(Touchplate/Microlite relay). The controller monitors the
status of the feedback contact and issues the pulse when
the requested command does not match the current relay
feedback.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
63
Separate Control Loop
This allows the user to add a single extra control loop to the controller.
The dual duct application uses AI-3 for the external flow sensor input.
For this reason, only temperature based sideloops are supported using
AI-4 (if discharge air sensor is not specified). The signal from the
analog input becomes the process variable of a PID controller. For
PAO and AO output types, PRAC is used to automatically tune the PI
controller. The output of the PID provides the command to the output
types that require a 0 to 100% signal (PAO, AO, DAO, EHS). If the
output type is the binary normally open or closed valve, the controller
uses the sideloop make limit and sideloop differential to operate the
valve. There are no point conditioning, interlocking, or Occupied
mode provisions in this loop. PRAC does not run with EHS, DAO, or
BOs. For more complete descriptions of the output types, see the
Input/Output Options topic in the Attributes and Parameters section of
this document.
Changing the VMA Parameter View
To change the VMA parameter view:
1. Open or create a VMA configuration file.
2. On the Options menu, click View.
3. Select the desired view from the four available options (Table 28).
Note:
Select the view before the controller is commissioned. Once
in Commissioning mode, the view cannot be changed until you exit
Commissioning mode.
Table 28: VMA Parameter Views
View
Description
Configuration
Shows only configurable parameters. This view is
recommended when modifying configuration files to match
specifications.
Commissioning
Shows calculated values in addition to the configurable
parameters. This view is recommended for use when
commissioning a controller at a job site.
Test and Balance
Shows a small set of parameters and values useful to test
and balance contractors.
Diagnostics
Shows the same information as the commissioning view
plus additional attributes of the application. Values of the
additional attributes are set by HVAC PRO software and
should not be modified by the user. Due to the quantity of
attributes in this view, updates are slow. Only use this view
for serious application problems.
64
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Configuring a VMA Application
To configure a VMA application:
1. Open or create a VMA application for the current VMA to be
configured.
2. Check the inputs to ensure the configuration matches the installed
sensor types and slot wiring.
3. Check the outputs to ensure the configuration matches any
applicable actuators, valves, relays, and wiring. Review the action
direction (direction to close or polarity) to ensure the controller
configuration matches the installed hardware.
4. Check the temperature setpoints and biases and modify to match
the job specifications.
5. Modify the flow setpoints and box flow configuration (area and
pickup gain) to match the VAV box specifications.
6. Check the configuration parameters for any additional features
(such as occupancy button or sensor, lighting, warmup) selected
during the question and answer session and modify to ensure they
meet any specified requirements.
7. Save the changes to the configuration file and download the new
file to the VMA controller. Alternately, the values can be changed
while commissioning the VMA controller and saved to the
controller and filed when exiting the Commissioning mode.
Note:
The Attributes and Parameters section describes all of the
parameters shown in the main views as well as most of the attributes
of the input and output options.
Commissioning a VMA Application
Note:
These commissioning steps are meant to provide a guideline
for some common tasks to perform during commissioning. This is not
an exhaustive commissioning guide and does not provide all
commissioning procedures required for a given job.
To commission a VMA application:
1. Open the file corresponding to the current VMA to be
commissioned.
2. Change the parameter view to Commissioning.
3. On the Commission menu, click Current Configuration.
4. Check the inputs to ensure that reliable and reasonable values are
being sensed by the controller.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
65
5. Override the outputs and verify that the installed hardware actuates
correctly. If a discharge air sensor is installed, the box heat
operation can be verified by checking for temperature rise when
the box heat is activated.
6. On the Action menu, click VAV Box Flow Test (single duct
applications only). See the Flow Test topic in the Key Concepts,
VMA Diagnostics section for more details.
7. On the Action menu, click Collect VAV Diagnostics. This tool
scans the N2 trunk for VMA controllers and collects temperature,
flow and actuator diagnostics for both single and dual duct
configurations. Controllers with large errors should be examined
more closely.
Testing and Balancing a VMA Single Duct Supply/Exhaust
Application
This section describes a recommended test and balance procedure for
balancing the VMA single duct supply/exhaust application using
HVAC PRO software. The testing and balancing procedure reconciles
the VMA flow measurements with the flow measurements of the
balancer. The tools needed for this procedure include a calibrated flow
measurement device suitable for the installed diffusers and a laptop
computer connected to the VMA either through the Zone Bus or
N2 Bus. For more information, see the Testing and Receiving Data
from Controllers chapter of the HVAC PRO User’s Guide
(LIT-63750416). Parameters are referenced using the following form:
(Group Name) Parameter Name.
Startup
Start up the test and balancing session.
Note:
Before starting, ensure that the Area and Flow Coefficient
are correct for both the supply and exhaust decks. Also record the
current Pickup Gain for each deck. These parameters can be found in
the Supply Flow Config and Exhaust Flow Config parameter groups.
1. Start HVAC PRO software.
2. On the File menu, click Open.
3. Open the file corresponding to the current VMA to be balanced.
4. On the Options menu, click View > Test and Balance.
66
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
5. On the Commission menu, click Configuration in Controller.
Note:
The pickup gains for the supply and exhaust decks can be
calibrated at any desired flow setpoint or averaged for multiple flow
setpoints. The exhaust flow setpoint always equals the supply flow
setpoint plus the current exhaust differential, which is a function of the
Occupancy mode. The steps required to calibrate at the minimum
cooling flow, the maximum cooling flow, and the heating flow
setpoints are given in the following sections.
Calibrate Pressure Sensor Offsets and Check for Leakage
To calibrate and check the system:
1. Issue an Autocalibration command. Override the parameter
(Autocalibration) Autocal Req to True and then release.
2. Override (VAV Box mode) Present Value to Shutdown Closed.
This keeps both dampers forced closed after the autocalibration is
complete to allow for leakage check.
3. Measure airflow to determine leakage at full closed position. If
amount of leakage is unacceptable, check damper actuators to
ensure they are in the fully closed positions. If they are not fully
closed, start again from Step 1.
4. Release the override on (VAV Box mode) Present Value.
Balance at Minimum Cooling Flow
To balance at minimum cooling flow:
1. Override (VAV Box mode) Present Value to Satisfied.
2. Wait for the VMA to reach the new flow setpoints.
3. Record the flow calculated by the VMA for the supply and exhaust
flows and measure the actual flows with a hood.
Note:
For each set of data, the pickup gain at the minimum flow is:
PickupGain MinFlow
⎛ MinFlow VMA
= ⎜⎜
⎝ MinFlow Hood
2
⎞
⎟⎟ ∗ PickupGain VMA
⎠
4. Release the override on (VAV Box mode) Present Value.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
67
Balance at Maximum Cooling Flow
1. Override (VAV Box mode) Present Value to Shutdown Open.
2. Wait for the VMA to reach the new flow setpoints.
3. Record the flow calculated by the VMA for the supply and exhaust
flows and measure the actual flows with a hood.
Note:
For each set of data, the pickup gain is:
PickupGain MaxFlow
⎛ MaxFlow VMA
= ⎜⎜
⎝ MaxFlow Hood
2
⎞
⎟⎟ ∗ PickupGain VMA
⎠
4. Release the override on (VAV Box mode) Present Value.
Balance at Heating Flow
To balance at heating flow:
1. Override (VAV Box mode) Present Value to Heating.
2. Wait for the VMA to reach the new flow setpoints.
3. Record the flow calculated by the VMA for the supply and exhaust
flows and measure the actual flows with a hood.
Note:
For each set of data, the pickup gain is:
PickupGain HtgFlow
⎛ HtgFlow VMA
= ⎜⎜
⎝ HtgFlow Hood
2
⎞
⎟⎟ ∗ PickupGain VMA
⎠
4. Release the overrides on (VAV Box mode) Present Value.
Finish
To finish testing and balancing:
1. Write the new pickup gain values for the supply and exhaust
configurations (Supply Flow Config and Exhaust Flow Config
groups).
2. Override the parameter (VAV Box mode) Present Value to
Satisfied.
3. Wait 10 seconds and then release the override. This returns the
application to the necessary automatic mode.
4. On the Commission menu, click Exit Commissioning Mode.
5. Click the Exit/Save Changes button.
68
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Table 29: VMA Single Duct Supply/Exhaust Application Test and
Balance Attributes Mapped to the Metasys Network
Attribute
Short Name
Long Name
Address
BOXMODE
Present Value
ADI 67
FLOWAREA
Area
ADF 24
VAV Box Mode
Supply flow
PKUPGAIN
Pickup Gain
ADF 25
FLOWCOEF
Flow Coefficient
ADF 26
SUPFLOW
Process Variable
ADF 58
SUPFLOSP
Setpoint
ADF 150
EFLOAREA
Area
ADF 21
EPKPGAIN
Pickup Gain
ADF 22
EFLWCOEF
Flow Coefficient
ADF 23
Exhaust Flow
EXHFLOW
Process Variable
ADF 59
EXHFLOSP
Setpoint
ADF 151
ACREQ
Autocalibration Request
BD 168
ACACT
Autocalibration Active
BD 66
Autocalibration
Testing and Balancing a VMA Dual Duct Application
This section describes a recommended test and balance procedure for
balancing the VMA dual duct application using HVAC PRO software.
The tools needed for this procedure include a calibrated flow
measurement device suitable for the installed diffusers and a laptop
computer connected to the VMA either through the Zone Bus or
N2 Bus. For more information, see the Testing and Receiving Data
from Controllers chapter of the HVAC PRO User’s Guide
(LIT-63750416). Parameters are referenced using the following form:
(Group Name) Parameter Name.
For this description, parameters are found in the Parameter list box and
are referenced with the group name in parentheses followed by the
parameter name. The reference form is: (Group Name) Parameter
Name.
Startup
To start up the testing and balancing session:
Before starting, ensure that the Area and Flow Coefficient
Note:
are correct for both the cold and hot decks. Also record the current
Pickup Gain for each deck. These parameters can be found in the Cold
Flow Config and Hot Flow Config parameter groups.
1. Start HVAC PRO software.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
69
2. On the File menu, click Open.
3. Open the file corresponding to the current VMA to be balanced.
4. On the Options menu, click View > Test and Balance.
5. On the Commission menu, click Current Configuration.
Calibrate Pressure Sensor Offsets and Check for Leakage
To calibrate pressure sensor offsets and check for leakage:
1. Issue an Autocalibration command. Override the parameter
(Autocalibration) Autocal Req to True and then release.
2. Force the dampers to remain shut. Override (VAV Box mode)
Present Value to Shutdown Closed. This keeps both dampers
forced closed after the autocalibration is complete to allow for
leakage check.
3. Measure airflow to determine leakage at full closed position. If
amount of leakage is unacceptable, check damper actuators to
ensure they are in the fully closed positions.
4. Release the override on (VAV Box mode) Present Value.
5. Wait for autocalibration to complete (if not already finished). The
parameter (Autocalibration) Autocal Active is True if the
autocalibration is still active.
Balance Cold Deck
If a cold deck flow sensor is used, balance the cold deck as follows.
1. Override the parameter (Command modes) Hot Deck Available to
False. This commands the hot deck damper fully closed.
2. Override (VAV Box mode) Present Value to Satisfied. This will
keep PRAC from trying to tune during the balancing overrides.
3. Ensure that the (Cold Deck) Area and Flow Coefficient are correct
for the cold deck. Also record the current Pickup Gain.
4. To balance at the minimum flow, override the parameter
(Command modes) Cold Deck Percent to 0%. Wait for VMA to
reach the new flow setpoint. Record the flow calculated by the
VMA and measure the actual flow with a hood.
5. To balance at the maximum flow, override the parameter
(Command modes) Cold Deck Percent to 100%. Wait for the
VMA to reach the new flow setpoint. Record the flow calculated
by the VMA and measure the actual flow with a hood.
Note:
The new pickup gain can be calculated using the minimum
or maximum flow data or both sets of data. For each set of data the
pickup gain is:
70
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
2
PickupGain MinFlow
⎛ MinFlow VMA
= ⎜⎜
⎝ MinFlow Hood
⎞
⎟⎟ ∗ PickupGain VMA
⎠
PickupGain MaxFlow
⎛ MaxFlow VMA
= ⎜⎜
⎝ MaxFlow Hood
⎞
⎟⎟ ∗ PickupGain VMA
⎠
2
6. Replace the (Cold Deck) Pickup Gain with the value calculated for
the minimum flow or maximum flow or an average of the two.
7. Release the overrides on (VAV Box mode) Present Value and
(Command modes) Hot Deck Available and Cold Deck Percent.
Balance Hot Deck
If a hot deck flow sensor is used, balance the hot deck.
1. Override the parameter (Command modes) Cold Deck Available to
False. This commands the hot deck damper fully closed.
2. Override (VAV Box mode) Present Value to Satisfied. This keeps
PRAC from trying to tune during the balancing overrides.
3. Ensure that the (Hot Deck) Area and Flow Coefficient are correct
for the hot deck. Also record the current Pickup Gain.
4. To balance at the minimum flow, override the parameter
(Command modes) Hot Deck Percent to 0%. Wait for VMA to
reach the new flow setpoint. Record the flow calculated by the
VMA and measure the actual flow with a hood.
5. To balance at the maximum flow, override the parameter
(Command modes) Hot Deck Percent to 100%. Wait for the VMA
to reach the new flow setpoint. Record the flow calculated by the
VMA and measure the actual flow with a hood.
Note:
The new pickup gain can be calculated using the minimum
or maximum flow data, or both sets of data. For each set of data the
pickup gain is:
2
PickupGain MinFlow
⎛ MinFlow VMA
= ⎜⎜
⎝ MinFlow Hood
⎞
⎟⎟ ∗ PickupGain VMA
⎠
PickupGain MaxFlow
⎛ MaxFlow VMA
= ⎜⎜
⎝ MaxFlow Hood
⎞
⎟⎟ ∗ PickupGain VMA
⎠
2
6. Replace the (Hot Deck) Pickup Gain with the value calculated for
the minimum flow or maximum flow or an average of the two.
7. Release the overrides on (VAV Box mode) Present Value and
(Command modes) Cold Deck Available and Hot Deck Percent.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
71
Balance Total Flow
If a total flow sensor is used, balance the total flow from the box.
1. Ensure that the (Total Flow) Area and Flow Coefficient are correct
for the total flow pickup. Also record the current Pickup Gain.
2. To balance at the minimum flow, override (VAV Box mode)
Present Value to Satisfied. Wait for VMA to reach the new flow
setpoints. Record the flow calculated by the VMA and measure the
actual flow with a hood. The total flow setpoint is equal to the box
minimum flow, the hot deck flow setpoint is equal to the hot deck
min flow, and the cold deck flow setpoint is equal to the difference
between the box minimum flow and hot deck flow setpoints.
3. To balance the total flow with the cold deck at its maximum flow,
override the parameters (Command modes) Cold Deck Percent to
100% and Hot Deck Percent to 0%. Wait for the VMA to reach the
new flow setpoints. Record the flow calculated by the VMA and
measure the actual flow with a hood.
4. To balance the total flow with the hot deck at its maximum flow,
override the parameters (Command modes) Cold Deck Percent
to 0% and Hot Deck Percent to 100%. Wait for the VMA to reach
the new flow setpoints. Record the flow calculated by the VMA
and measure the actual flow with a hood.
Note:
The new (Total Flow) Pickup Gain can be calculated using
any data. For each set of data the pickup gain is:
PickupGain MinFlow
⎛ MinFlow VMA
= ⎜⎜
⎝ MinFlow Hood
2
⎞
⎟⎟ ∗ PickupGain VMA
⎠
2
PickupGain C lg MaxFlow
⎛ C lg MaxFlow VMA
= ⎜⎜
⎝ C lg MaxFlow Hood
⎞
⎟⎟ ∗ PickupGain VMA
⎠
PickupGain HtgMaxFlow
⎛ HtgMaxFlow VMA
= ⎜⎜
⎝ HtgMaxFlow Hood
⎞
⎟⎟ ∗ PickupGain VMA
⎠
2
5. Replace the (Total Flow) Pickup Gain with the value from that
calculated for the box minimum flow, one of the maximum flows,
or an average of the two or more.
6. Release the overrides on (VAV Box mode) Present Value and
(Command modes) Cold Deck Percent and Hot Deck Percent.
72
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Finish
To finish test and balancing:
1. Override the parameter (VAV Box mode) Present Value to
Satisfied. Wait 10 seconds and then release the override. This
returns the application to the necessary Automatic mode.
2. On the Commission menu, click Exit Commissioning Mode.
3. Click the Exit/Save Changes button.
Note:
The test and balance application overrides also can be done
via an Operator Workstation (OWS) if a second person is in
communication with the person making the overrides on the OWS.
Table 30 shows the mapping for the required parameters referenced in
the previous sections. Figure 13 shows the VAV Box mode
enumeration set.
Table 30: VMA Dual Duct Application Test and Balance Attributes
Mapped to the Metasys Network
Attribute
Short Name
Long Name
Address
BOXMODE
Present Value
ADI 67
VAV Box Mode
Command Modes
CDAVAIL
Cold Deck Available
BD 75
HDAVAIL
Hot Deck Available
BD 76
CDPERCNT
Cold Deck Percent
ADF 71
HDPERCNT
Hot Deck Percent
ADF 72
CDAREA
Area
ADF 11
CDPKUPGN
Pickup Gain
ADF 12
CDFLCOEF
Flow Coefficient
ADF 13
CDFLOSP
Setpoint
ADF 65
CDFLOW
Cold Deck Flow
ADF 36
HDAREA
Area
ADF 14
HDPKUPGN
Pickup Gain
ADF 15
HDFLCOEF
Flow Coefficient
ADF 16
Cold Deck
Hot Deck
HDFLOSP
Setpoint
ADF 66
HDFLOW
Hot Deck Flow
ADF 37
TOTAREA
Area
ADF 17
TOTPKPGN
Pickup Gain
ADF 18
TOTFCOEF
Flow Coefficient
ADF 19
TOTFLOSP
Setpoint
ADF 67
TOTFLOW
Total Deck Flow
ADF 38
ACREQ
Autocal Request
BD 70
ACACT
Autocal Active
BD 60
Total Flow
Autocalibration
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
73
Troubleshooting
Table 31 describes known problems and their solutions.
Table 31: Troubleshooting VMA Controllers
Error/Condition
Problem
Solution
VMA Application
Disappears after
HVAC PRO
Software Reports
Download
Complete
After HVAC PRO software
completes a download, the VMA
must still complete an internal
archive. If the VMA is disconnected
from 24 VAC power immediately
after HVAC PRO software indicates
that the application download is
complete, the application is lost.
This problem only pertains to
HVAC PRO Release 7.01 or earlier.
Use one of the following methods to correct the
problem:
•
Upgrade to HVAC PRO Release 7.02 or
later, which is updated to report download
complete after the VMA completes its
internal archive (for single VMA downloads).
•
Allow the VMA to remain powered for an
additional 60 seconds after HVAC PRO
software indicates that the download is
complete.
•
Select Controller Information from the Action
menu and wait until device status indicates
that the VMA is operational.
Heating Does
Not Operate
When File
Upgrade is
Performed with
HVAC PRO
Release 7.01
If HVAC PRO Release 7.01 is used
to upgrade a VMA configuration file
originally created in HVAC PRO
Release 7.00, the VMA Box mode
remains in Satisfied state and does
not transition to Heating mode even
when the zone temperature is less
than the setpoint and the Heating
Available parameter is True.
Use one of the following methods to correct the
problem:
VMA Does Not
Come Online
The VMA may be unable to
communicate on the same N2 trunk
as some third-party vendor devices
because the VMA sends data other
than American Standard Code for
Information Interchange (ASCII) text.
If this problem exists, the VMA does
not come online when it is added to
the N2 trunk where the vendor
device is connected. If the vendor
device is added to the N2 after the
VMAs are online, the VMAs will go
offline.
This is not necessarily a problem with the VMA;
it may be a problem with the communication
firmware of the vendor device. To determine
whether this problem exists, disconnect all
vendor devices and see if the VMA comes
online. If so, contact the vendor to upgrade the
firmware of the vendor device. The VTAC 7 and
GV3000 drives from Reliance Electric are the
only devices currently known to cause this
problem, and they can be successfully upgraded
by the manufacturer.
N2 addresses of 254 and/or 255
have been used.
N2 addresses of 254 and 255 are reserved for
VMA broadcast messages. Use only
Addresses 1-253. See Mounting and Wiring
Variable Air Volume Modular Assembly (VMA)
1400 Series Controllers Technical Bulletin
(LIT-6363125) for more information.
Continued on next page . . .
•
Use HVAC PRO Release 7.02 or later to
open, save, and download the VMA
configuration file.
•
Select Upgrade Controllers from the Upload
menu in HVAC PRO Release 7.01 or later.
74
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Error/Condition
(Cont.)
Problem
Solution
Incorrect Metric
Value for Remote
Setpoint (AI2)
The Metric default value for the
Remote Setpoint (AI2) option for a
VMA application is incorrect in
HVAC PRO Release 7.02. The
Metric Output Range High
parameter is incorrectly defaulted to
18, and it should be 28.
Note:
User-Defined Ranges for
the VMA were not available until
HVAC PRO Release 7.02. This is
only a problem for new VMA
applications using the remote
setpoint.
Workaround:
1. Manually adjust the Output High Range
parameter for the Remote Setpoint AI2. The
correct default values for the AI are shown in
Table 32, although any combination of
values is allowable.
2. Save the application.
3. Download and commission the VMA.
Permanent Solution:
Install Configuration Tools Release 7.03 and
recreate the application (do not upgrade). Save
and download.
No Damper
Control when
Supply Delta P
(DP) Becomes
Unreliable
In HVAC PRO Release 7.02, if the
Supply Delta P (DP) analog input
ever becomes unreliable, the VMA
commands the damper to a fixed
position and does not modulate the
damper correctly.
Workaround:
1. Replace the existing file in the
C:\Winpro\Modules directory with the
corrected logic file (sdvmalg4.mod) available
on The Advisor.
2. Upgrade all affected controllers.
Note: The application revision does not
change.
Permanent Solution:
1. Install HVAC PRO Release 7.03.
2. Upgrade all affected controllers.
Note: The application revision does not
change.
Non-default
Analog Outputs
(AOs) and Binary
Outputs (BOs)
Incorrectly
Upgraded
When using HVAC PRO
Release 7.02 or earlier to upgrade
VMA applications, non-default AOs
and BOs are incorrectly upgraded.
HVAC PRO software indicates the
points are working correctly. The
VMA is actually driving the default
point with the commanded voltage
(measured at the hardware). Using
the default AO or BO number does
not present the problem. It is only
when the default AO or BO number
is changed, for example AO-1
moved to AO-2.
Continued on next page . . .
Workaround:
1. Rebuild the application using the
Question/Answer (Q/A) procedure and
adjust the AO numbers.
2. Save and download the application to the
affected controllers.
Permanent Solution:
1. Install HVAC PRO Release 7.03. Use this
release to upgrade VMA applications
created in HVAC PRO Releases 7.00, 7.01,
or 7.02.
2. If the application was upgraded using
HVAC PRO Release 7.02, the only solution
is to rebuild the application, save, and
download.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Error/Condition
(Cont.)
Problem
Solution
Incorrect DDL
Code for Electric
Heating Stage
(EHS) Outputs
HVAC PRO Release 7.02 or earlier
generates incorrect Data Definition
Language (DDL) code for VMA
applications with EHS outputs. This
does not affect operation in the VMA
but does result in incomplete
information if the point is mapped.
The point displays either OFF or
Stage for the states. It should
display OFF, Stage1, Stage2, or
Stage3.
Workaround:
Edit the .ddl file and manually add the stage
numbers in the text field and delete the extra
stages. The following are examples of the
incorrect and correct .ddl for the EHS box heat
parameters:
Incorrect:
CSMS
"ADI140",Y,Y,"BOXHTG","Off",0,"Stage",1,
"Stage ",2,"Stage ",3,"Stage ",4,"Stage",5,
"Stage ",6,"Stage ",7,"Stage ",8
CSMS
"ADI2",N,N,"BHACTSTG","Off",0,"Stage",1,
"Stage ",2,"Stage ",3,"Stage ",4,"Stage",5,
"Stage ",6,"Stage ",7,"Stage ",8
Correct:
CSMS
"ADI140",Y,Y,"BOXHTG","Off",0,"Stage1",1,
"Stage2",2,"Stage3",3
CSMS
"ADI2",N,N,"BHACTSTG","Off",0,"Stage1",1,
"Stage2",2,"Stage3",3
Permanent Solution:
1. Install HVAC PRO Release 7.03.
2. Open the configuration files.
3. Save the file with the Generate .DDL box
checked.
VMA Binary
Inputs (BIs) and
Binary Outputs
(BOs) Are Offline
VMA BIs and BOs are offline to
Metasys software Release 10.0 or
earlier after commissioning with
HVAC PRO Release 7.02. This is
not an HVAC PRO software
problem; it is a Metasys Operator
Workstation (OWS) problem. The
BIs and BOs, which are online to
Metasys software prior to
commissioning, go offline during
commissioning, but never return to
online after commissioning is
completed. Other points mapped
into the controller return to online.
Continued on next page . . .
Workaround:
From Metasys software Release 9.01c or 10.0,
override the points and release. This
re-establishes communication and brings them
online.
Permanent Solution:
Install a revision of Metasys software later than
Release 10.0.
75
76
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Error/Condition
(Cont.)
Problem
Solution
Intermittent VMA
Download
Failures over
Ethernet
Networks
Intermittent communication errors
are experienced while running
HVAC PRO software on a Metasys
OWS.
The errors seem restricted to
Ethernet N1 installations while doing
VMA controller downloads. A
possible cause is unusually high
N1 Ethernet traffic.
Try to analyze source of N1 traffic. Try
performing the operation (upload, download, and
commission) during off-peak times of the day.
There is no software solution currently available
that addresses this specific problem.
VMA Download
Failures over
Dial-Up Networks
HVAC PRO Release 7.02 fails to
download VMAs over a dial-up
network.
HVAC PRO software gets to 8%
before a message box appears
indicating the download failed. This
may be caused by timing problems.
Avoid attempting to download a VMA over a
dial-up network. Download directly through the
N2 trunk.
Proportional
Band Resets to
Values That Are
Too Large
For some configurations, when
VMA1400 Series controllers exit a
state in which no flow range is active
(Satisfied or Shutdown mode), the
proportional band may be reset to a
very large value. When this occurs,
the VMA operates sluggishly and
does not accurately control the zone
temperature. This problem occurs in
HVAC PRO software releases prior
to Release 8.01.
After updating HVAC PRO software to
Release 8.01, upgrade current installations of
VMA1400 controllers by clicking on Upgrade
Controllers in the Upload menu in HVAC PRO
software.
Single Duct
Application
Download Fails
at about 25%
The Question and Answer paths for
some Single Duct and
Supply/Exhaust applications exceed
the allowed file size. When this
occurs, the download to the
controller fails at about 25%
complete. This occurs with VMA
firmware C01 and HVAC PRO
software Release 8.01.
Workaround:
1. Replace the existing file in the
C:\Winpro\Modules directory with the
corrected logic file (sdvmalg4.mod) available
on The Advisor.
2. Upgrade all affected controllers.
Tuning error occurs when the VMA
is not commanded to shutdown
when the AHU is off.
Other possible causes (if VMA is
synchronized with AHU operation)
are that the zone sensor time
constant (either due to the room
dynamics or the sensor placement)
is very long or the controlled output
is not responding correctly.
Upgrade to HVAC PRO software Version 8.03
(Single Duct Application Revision 5 and Dual
Duct Application Revision 3). This software
revision interlocks PRAC with the starved box
flags to prevent tuning when supply air is not
available. If PRAC still tunes the proportional
band below the Min PID Prop Band (default
value is 0.5°C [1.0°F]), the proportional band
resets to five times the minimum value.
PRAC Tunes PID
Proportional
Band Very Small
(Less Than 0.1)
Continued on next page . . .
Permanent Solution:
Upgrade to HVAC PRO software Release 8.03.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
77
Error/Condition
(Cont.)
Problem
Solution
TE-6700 LED
Blinks when
Occupancy Mode
Is Not Standby
The LED on the TE-6700 sensor
blinks when the VMA Occupancy
Mode is not Standby.
Workaround:
1. Download the hpro802patch.zip file from the
Configuration Tools Resource Page on The
Advisor. Extract the files to a temporary
directory. Replace the logic file in the
C:\Winpro\Modules directory with the
corrected logic file (sdvmalg4.mod). Replace
the database files in the C:\Winpro\Data
directory with the corrected database files
(sdvmaqa4.dbt, sdvmpar4.dbf,
sdvmpar4.ndx)
2. Upgrade all affected controllers.
Permanent Solution:
Upgrade to HVAC PRO software Release 8.03.
Write to
Controller Fails
Parallel Fan
Cycles On/Off as
Zone Temp
Hovers Around
the Heating
Setpoint
Error message appears, “Write to
controller failed” when you attempt
to change Analog Input User Range
Attributes.
For HVAC PRO 8.05 or later, during
commissioning, the user can attempt
to write to the Input Range Low,
Input Range High, Output Range
Low and Output Range High
attributes of the Analog Inputs. Only
VMA firmware Revisions C04 or
later support this capability. Older
versions do not allow the change
which causes error.
Workaround:
1. Upload file from controller.
2. Change attributes and save.
3. Download updated file to controller.
The heating sequencing was
simplified in Application Revision 5
inadvertently allowing the VAV Box
Mode to enter heating for only one
application execution only when the
zone temperature is below setpoint
for one execution and above
setpoint for the next execution.
The application was fixed at HVAC PRO 8.05,
but the application revision was not changed.
To update the application code, use
HVAC PRO 8.05 or later.
Permanent Solution:
Upgrade VMA firmware to Revision C04 or later.
Table 32: Default Values for Remote Setpoint AI
Parameter
Default
Value
Description
Min Value
12C (65F)
Minimum reliable value allowed for the AI (does not affect the AI range)
Max Value
28C (85F)
Maximum reliable value allowed for the AI (does not affect the AI range)
Input Range Low
0
Low end for the input to the AI range equation
Input Range High
1660
High end for the input to the AI range equation
Output Range Low
12C (65F)
Low end for the output of the AI range equation
Output Range High
28C (85F)
High end for the output of the AI range equation
78
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
VMA Firmware Revisions
Table 33 shows the VMA firmware revision history. Each subsequent
firmware version includes the features and fixes of the previous
version plus any modifications listed. If you require any of these new
capabilities, perform a Download > VMA Code operation using
HVAC PRO software. Refer to the Downloading Configurations and
VMA Code chapter of the HVAC PRO User’s Guide (LIT-63750404).
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
79
Table 33: VMA Firmware Revision History
HVAC PRO
Revision
VMA
Firmware
Revision
Description of Changes
7.00
B04
Original Release
7.01
B04
Original Release
7.02
B12
Support added for User Range Ohms and User Range Volts input ranges for
analog inputs.
The Archive Memory increased to handle larger applications.
7.03
B15
When an AI has been set to User Range Ohms or Volts, the controller uses
Input Range High and Low attributes to validate the input can handle the
setup and/or select the correct auto ranging channel. For example, AI1 and
AI4 have two internal ranges, each with a different input range that results in
different resolutions. If the Input Range High/Low is set to 1200/800 ohms
respectively, then the controller automatically chooses the channel with the
smaller input range (higher resolution).
The SMO damper controller now reduces the number of false Stalled During
Positioning Reliability errors. This error makes the Output attribute unreliable
and displays ????.
The PAO object now correctly calculates/displays the Resync Remaining
attribute. This only affects the value displayed in HVAC PRO software, not
the control of the PAO.
The Archive Memory increased to handle larger applications.
8.00
C00
No changes other than revision number. The revision change was made to
be consistent with literature statements that the TMZ digital room sensor
would be supported at VMA firmware revision C00.
8.01
C01
The operation of the Duration Adjust Output (DAO) modified to ensure that
when the Present Value is greater than the Min Off Limit, the binary output
remains on continuously. In some cases (with previous firmware), the binary
output would turn off for a fraction of a second one time each period. This
problem was most noticeable with very large applications (many options
selected) when commissioning the controller.
8.03
C02
Added support for Remote Sensor Applications using the TMZ1600.
The setpoint now cannot be changed from the TMZ1600 if it is overridden.
Updated routine for calculating the Bytes Used value that is displayed in
Device Info.
Modified the method for overdriving a 3-wire proportional actuator.
Added compatibility features for latest release of VMA Balancer Tool
(VBT Version 2.0)
Modified the Stepper Stall detection logic to reset the reliability on change of
direction.
8.04
C03
TMZ software lockout retained on power cycle.
Allows N30 ADJUST command of the Common Setpoint.
Allows Occupancy Timer to be set to greater than 9 hours.
Added COV message caching to improve N2 performance and reduce N2
Offline/retries.
8.05
C04
Analog Input attributes Input Range Low, Input Range High, Output Range
Low, and Output Range High updated to allow modification after the
application downloads to the controller. The user can change these attributes
using either the AIM Spreadsheet Download tool or HVAC PRO 8.05 or later.
Modified the Stepper (SMO) object so that its position (Output attribute) is no
longer associated with the Reliability of the object.
80
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Attributes and Parameters
Input/Output Options
The VMA applications support analog and binary inputs, analog and
binary outputs, as well as some additional output types. The operation
of these inputs and outputs may be different in the VMA and may have
new features that were not available in previous controllers. For that
reason, this section describes the basic operation of each of these input
and output types and most of the attributes.
Analog Input
The analog input provides the main process information to the VMA,
including temperature and velocity pressure measurements and
occupant setpoint adjustment. The default attributes of this input are
set up by the configuration tool, depending on the type of signal being
measured. If the analog input is unreliable at startup, the controller
automatically uses the startup value. If a reliable value is read and then
the input becomes unreliable, the controller uses the last reliable value
received. Table 34 describes the attributes for the analog input.
Note:
Firmware Revision C00 or later is required to support all of
the additional setup options for the AI ranges.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
81
Table 34: Analog Input (AI) Attributes
Attribute Name
Description
Present Value
The current reading for the analog input
Reliability
The reliability of this analog input
Startup Value
The value used as a reliable output until the first reliable reading is received from the
hardware
Units
The engineering units for this analog input
Min Value
This is the lowest value that will be reliable. This does not define the low end for the
range equation.
Max Value
This is the highest value that will be reliable. This does not define the high end for the
range equation.
Display Precision
This sets the number of decimals for display.
COV Increment
This is the amount the AI must change before a value is sent to any object that has
signed up for the Present Value.
Setup
This attribute defines the ranging for the AI. The VMA has some restrictions on which
ranges can be used on which analog input.
AI-1, AI-2, and AI-4 support: Nickel F, Nickel C, Platinum F, Platinum C, NTC F,
NTC C, Silicon F, Silicon C, Poten 65 to 85 F,
Poten 12 to 28 C, Poten 55 to 85 F, Poten 13 to 30 C,
Poten -5 to 5 F, Poten -3 to 3 K and User Range Ohms
AI-3 supports:
Percent RH, VDC 0 to 10, and User Range Volts
AI-5 supports:
DeltaP in w.c., DeltaP Pa, and User Range Volts
Offset
This is the offset to eliminate errors due to wiring or ADC offsets.
Anti-Spike
This enables or disables spike filtering for the analog input. The adaptive, anti-spike
filter prevents a momentary spike in the signal from affecting the output of the
controller. For a given sample, the signal is limited to a change no larger than the
spike window. If the signal hits the edge of the spike window, the window opens
exponentially larger during subsequent samples to allow real signal changes to pass.
After the signal settles, the window closes exponentially back to the original spike
window.
Spike Fraction
The amplitude of change that is clipped is called the spike window.
Spike Window = Spike Fraction * (Max Value – Min Value)
Filter Order
This attribute chooses the filter type.
None – no filtering. This is needed for flow control with P-Adaptive due to the adaptive
noise band and extremely fast process speed.
First – first order exponential filter that uses the Filter Weight to set its response.
Second – second order butterworth filter that does exceptional low pass filtering and
should be used for most applications. The process speed is used to set its response.
Filter Weight
This parameter sets the time constant of a first order filter.
Process Speed
This sets the second order filter for the speed of your process. Use Fast for processes
that can change within a minute or less. Processes that respond slower should use
Normal.
Input Range Low
Input Range High
Output Range Low
Output Range High
If User Range Volts (AI-3 or AI-5 only) or User Range Ohms (AI-1, AI-2, or AI-4 only)
is selected, the line equation for the user-defined input is defined using the
four attributes Input Range Low, Input Range High, Output Range Low, and Output
Range High. Input Range Low and High default to the ends of the typical input range
(0-10 volts or 0-1660 ohms). The maximum measurable resistance for AI-1, AI-2, and
AI-4 is 21,000 ohms, and the maximum voltages for AI-3 and AI-5 are 16.5 volts and
5.0 volts, respectively. Input Range Low must be less than Input Range High. To
define a line equation with a negative slope, set Output Range High to a value less
than Output Range Low.
82
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Binary Input
The binary input provides digital feedback to the controller from
sensors including the temporary occupancy button, occupancy sensor,
and low limit contact. Table 35 describes the attributes for the binary
input.
Table 35: Binary Input (BI) Attributes
Attribute Name
Description
Present Value
The current reading for the binary input
Polarity
Normal - Present Value is active based on a closed contact.
Reverse - Present Value is active for an open contact.
Reliability
The reliability of this binary input
Startup Value
The value used as reliable until the first reliable reading is received from the hardware.
States Text
This attribute selects the units for this BI object.
Debounce
This is the debounce filter time for this BI object.
Analog Output
The analog output provides a proportional voltage output signal.
Table 36 describes the attributes for the analog output.
Table 36: Analog Output (AO) Attributes
Attribute Name
Description
Present Value
The current command to the analog output
Output
The current command to the hardware in % of 0 to 10 volts DC
Reliability
The reliability of this analog output
Relinquish Default
The value used as a reliable output on startup until the first command is issued to this
object. With a value of Null, no command is issued until the first command is received.
Units
The engineering units for this analog output
Min Value
This is the lowest value that is accepted at the input.
Max Value
This is the highest value that is accepted at the input.
Display Precision
This sets the number of decimals for display.
COV Increment
This is the amount the AI must change before a value is sent to any object that has
signed up for the Present Value.
Setup
This attribute defines the output type for the AO. The VMA only supports voltage
outputs at this time.
Deadband
This provides a deadband before the actual output changes.
Min Out Value
Max Out Value
The Min Out Value and Max Out Value attributes define the output when the input is at
Min Value and Max Value. In the VMA, the Present Value is always 0-100% coming
from the PID, so the Min Out Value corresponds to the Output with an input signal
of 0% and the Max Out Value corresponds to the Output with an input signal of 100%.
For example, an EP-8000-2 at factory calibration, if you want 10 psi for the full closed
position and 3 psi for the full open position;
Min Out Value = 50% (5 VDC)
Max Out Value = 15% (1.5 VDC)
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
83
Binary Output
The binary output is a 24 V output suitable for activating a relay, fan
starter, or two-position heating device. Table 37 describes the
attributes for the binary output.
Binary outputs are also to be used by other output types (described in
the following sections) that provide special functionality. The slot of
any BO reserved by these special output collections (PAO, DAO,
EHS, Start Stop Output [SSO]) must be changed by modifying the slot
attribute of the output collection.
Table 37: Binary Output (BO) Attributes
Attribute Name
Description
Present Value
The current command to the binary output
Output
The current command to the actual hardware
Polarity
Setup = Maintained: Normal - normally closed, Reverse - normally open
Setup = Momentary: Normal - pulse on active, Reverse - pulse on inactive
Setup = Pulse: no effect on output action
Reliability
The reliability of this binary output
Relinquish Default
The value used as a reliable output on startup until the first command is issued to this
object. With a value of Hold, no command is issued until the first command is
received.
States Text
The engineering units for this binary output
Setup
For QA configured BO, this has been set by the QA path and should not be changed.
Momentary - for polarity = normal, BO issues pulse equal to Pulse Width when the
Present Value changes to True or Active.
Maintained - for polarity = normal, BO is active when Present Value is True or Active.
Pulse - BO issues pulse equal to Pulse Width when the Present Value changes value.
Pulse Width
This is the width of the pulse when Momentary or Pulse is selected as Setup. When
Maintained is selected, this is not used.
Heavy Equip Delay
This is the amount of time that elapses after this output is started before a second
output could be started. This feature is not currently available.
84
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Stepper Motor Object
The Stepper Motor Object (SMO) controls the VMA 1410/1420
integral actuator. This actuator is a stepper motor that allows fast
response with fine step resolution (23,000). No BOs are used. The
SMO output is set up for incremental commands. Incremental
commands are accepted that drive the actuator open or closed
(-100% to 100%). For example, a command of 10% more from its
current position tells the actuator to open 10% from its current
position, while a command of -10% tells the actuator to close
10% from its current position. An incremental command of 0% causes
no change in actuator position. Typical commands from the flow
controller are between -5% to 5%. Table 38 describes the attributes for
the Stepper Motor Object.
Table 38: Stepper Motor Object (SMO) Attributes
Attribute Name
Description
Present Value
This is the current command to the integrated actuator.
Setup
This describes the object’s response to commands. Incremental indicates the
command contains direction and magnitude typically in the range -100 to 100%.
Positional means the command is an absolute position in the range of 0 to 100%. This
should be Incremental for the integral actuator. If the Delta P sensor becomes
unreliable, the Flow Loop switches the actuator setup Positional.
Reliability
This is the reliability of this stepper motor object.
Relinquish Default
This is the value used as a reliable output on startup until the first command is issued
to this object. With a value of Null, no command is issued until the first command is
received.
COV Increment
This is the amount the attributes must change before a value is sent to any object that
has signed up for the Present Value or Output.
Display Precision
This sets the number of decimals for display.
Deadband
This provides a deadband before the actual output changes.
Direction to Close
This defines the direction of actuator rotation when driven closed.
Startup Mode
This tells the actuator what it should do to determine the current Output on a startup.
This has been setup by the QA path and should not be changed.
Resync Mode
This defines how the Stepper Motor Object should synchronize the Output.
Resync Period
This sets the time period to allow a resync of the output. Once resynched, the output
does not resync again until this timer expires.
Resync Window
This sets the window for Positional mode.
Stroke Time
This is the integral actuators stroke time. Unless the initial autorange is disabled, the
stroke time is calculated by the application during the startup autocalibration and
should not be changed.
Output
This is the computed position of the actuator in %.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
85
Position Adjust Output
The Position Adjust Output (PAO) performs floating control of 3-wire
actuators using two triac (BO) outputs. With the correct stroke time
entered, the duration and direction of travel is calculated to reposition
the actuator based on the positional input. The open or close triac is
commanded for the correct duration until the actuator position matches
the input. The PAO can be set up to accept either incremental or
positional commands. Table 39 describes the attributes for the PAO.
Table 39: Position Adjust Output (PAO) Attributes
Attribute Name
Description
COV Increment
This is the amount the attributes must change before a value is sent to any object that
has signed up for the Present Value or Output.
Deadband
This provides a deadband before the actual output changes.
Display Precision
This sets the number of decimals for display.
Min Pulse Width
This is the minimum pulse issued if the actuator had stopped moving.
Polarity
Normal - Slot A defines the open BO, Slot B defines the close BO.
Reverse - Slot B defines the open BO, Slot A defines the close BO.
Output
This is the computed position of the hardware in %.
Present Value
This is the current command to the position adjust output.
Reliability
This is the reliability of this position adjust output.
Relinquish Default
This is the value used as a reliable output on startup until the first command is issued
to this object. With a value of Null, no command is issued until the first command is
received.
Resync Amount
This is the maximum amount of movement in percent that the object overdrives in any
Resync Period.
The Resync Amount is reset whenever the actuator changes direction. This ensures
that the actuator is able to fully return the valve or damper to its stop.
Resync Period
This sets the time period to allow a resync of the output. Once resynched, the output
does not resync again until this timer expires.
Starting with firmware revision C02 and Application Revision 5 for Single Duct
applications and Application Revision 3 for Dual Duct applications, a Resync Period of
zero indicates that the Resync Amount is not reset on a periodic basis, but only on
change of direction. This is the new default setup based on information received from
actuator manufacturers.
Note:
After upgrading the firmware to C02, the PAO objects in existing applications
must manually have the Resync Period set to zero and the Resync Amount set to
100% to take advantage of this feature.
Reversal Delay
This is the amount of time the actuator stops before changing directions.
Setup
This describes the object’s response to commands. Incremental indicates the
command contains direction and magnitude typically in the range -100 to 100%.
Positional means the command is an absolute position in the range of 0 to 100%.
This was set by the QA and should not be changed.
Slot A
This is the first binary output used by this object. This attribute allows the slot of the
reserved BO to be changed.
See Polarity above for open/close definition.
Slot B
This is the second binary output used by this object. This attribute allows the slot of
the reserved BO to be changed.
See Polarity above for open/close definition.
Stroke Time
This is the actuator’s stroke time used to calculate the binary output command duration.
86
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Duration Adjust Output
The Duration Adjust Output provides proportional control using
one triac (BO) output that is active (on) for the input percentage of the
period. It is inactive (off) for the remainder of the period. When the
input percentage is greater than the minimum off limit parameter, the
output is turned on. When the input percentage is less than the
minimum on limit parameter, the output is turned off. This would
typically be used for solid-state electric heaters. Table 40 describes the
attributes for the Duration Adjust Output.
Table 40: Duration Adjust Output (DAO) Attributes
Attribute Name
Description
Output
This is the percent of the period that the binary output is on.
Relinquish Default
This is the value used as a reliable output on startup until the first command is issued
to this object.
Present Value
This is the current command to the duration adjust output.
Slot
This is the binary output used by this object. This attribute allows the slot of the
reserved BO to be changed.
Reliability
This is the reliability of this duration adjust output.
COV Increment
This is the amount the attributes must change before a value is sent to any object that
has signed up for the Present Value or Output.
Display Precision
This sets the number of decimals for display.
Period
This is the cycle time for the Duration Adjust Output. The on time is a percentage of
this.
Deadband
This provides a deadband before the actual output changes.
Min Off Limit
When the Present Value is greater than or equal to the Min Off Limit, the binary output
turns On continuously. Calculate the minimum off time as follows:
Minimum BO off time = Period * (100 - Min Off Limit) / 100
Min On Limit
When the Present Value is less than or equal to the Min On Limit, the binary output
turns Off continuously. The minimum time that the output turns on is as follows: Period
* Min On Limit / 100
Electric Heat Sequencer
The Electric Heat Sequencer allows multiple BOs to be sequenced
based on a single input command. When it is set up as proportional, it
energizes the BOs when the heating command is greater than the
corresponding make limit and de-energizes the BOs when it is less
than the corresponding break limit. The make limits and break limits
must be of an increasing value for each stage. The make limit must be
larger than its corresponding break limit.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
87
When the EHS is set up as integral, there is only one make limit and
one break limit. The make limit must be greater than the break limit. In
this setup, the first BO energizes after the make limit is exceeded by
the heating command. The second BO energizes after the make limit is
exceeded again and the interstage on delay has expired. The BOs are
de-energized in reverse order. The second BO de-energizes after the
heating command drops below the break limit. After the heating
command drops below the break limit again and the interstage off
delay expires, the first BO is de-energized.
The interstage delays apply to both integral and proportional setups.
Table 41 describes the attributes of the Electric Heat Sequencer.
Table 41: Electric Heat Sequencer (EHS) Attributes
Attribute Name
Description
Present Value
This is the requested stage of the electric heat sequencer. The Present Value is an
enumerated value calculated based on the Input and the Make and Break Limits. The
Present Value can be overridden independent of the Input to command the electric
heat sequencer to a particular stage.
Actual Stage
This is the current stage of the electric heat sequencer. The Actual Stage indicates
which of the binary outputs are currently active. If the Instant All Off attribute is True,
the Actual Stage is set to zero and all outputs are shut off. The Actual Stage may also
not be equal to the Present Value if the Interstage On Delay or Interstage Off Delay for
the Actual Stage has not been satisfied.
Input
This is the current command to the electric heat sequencer. This value from 0-100%
comes from the Heating PID and is used to calculate the Present Value. When the
Input exceeds the Make Limit, the next stage is started if the Interstage On Delay is
satisfied. When the Input drops below the Break Limit, the last stage on is turned off if
the Interstage Off Delay has been satisfied.
Instant All Off
When True, the electric heat sequencer turns all outputs off immediately.
Interstage Off
Delay
This is the time that the previous stage must be off before another stage is turned off.
Interstage On
Delay
This is the time that the previous stage must be on before another stage is turned on.
Number of Stages
This specifies the number of outputs. This has been set up by the QA path and should
not be changed.
Output State
This array holds the current state of all binary outputs.
Reliability
This is the reliability of the electric heat sequencer.
Setup
Proportional - Each stage has its own make and break limits.
Integrational - All stages have the same make and break limit. When the command
exceeds the make limit, the next stage is started if the interstage on delay is satisfied.
When the command drops below the break limit, the last stage on is turned off if the
interstage off delay has been satisfied.
Slot
This is an array defining the binary output for each stage. This attribute allows the slot
of the reserved BO to be changed.
Break Limit
This is the array of break limits for Proportional or the break limit for Integrational.
Make Limit
This is the array of make limits for Proportional or the make limit for Integrational.
States Text
This defines the units for the Present Value and Actual Stage attributes.
Output States Text
This defines the units for the Output State (on/off) array.
88
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Start Stop Output
The start stop output is used to control a momentary lighting relay
(GE RR-7 relay). Two triac (BO) outputs are used. The first (start)
triac pulses on when lighting should be on and the second (stop) triac
pulses on when lighting should be off. Table 42 lists and describes the
SSO Attributes.
Table 42: Start Stop Output (SSO) Attributes
Attribute Name
Description
Present Value
This is the current command to the start - stop output.
Output
This is the current command to the actual hardware.
Polarity
Normal - Slot A defines the ON binary output.
Reverse - Slot B defines the ON binary output.
Reliability
This is the reliability of this start - stop output.
Relinquish Default
This is the value used as a reliable output on startup until the first command is issued
to this object. With a value of Hold, no command is issued until the first command is
received.
States Text
This attribute selects the units for this object.
Slot A
This is the first binary output used by this object. This attribute allows the slot of the
reserved BO to be changed.
See Polarity above for ON command definition.
Slot B
This is the second binary output used by this object. This attribute allows the slot of
the reserved BO to be changed.
See Polarity above for ON command definition.
Heavy Equip Delay
This is the amount of time that elapses after this output is started before a second
output could be started. This feature is not implemented.
Pulse Width
This is the width of the pulse issued when the Present Value changes.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
89
VMA Single Duct Parameters
The VMA has adjustable parameters, but most do not require changes.
Changing parameters may cause the controller to malfunction. We
offer this guide to provide a reference for the application parameters
used to configure VMA single duct application.
This topic has four groups of tables. Table 43 shows which parameters
are in each of the main views. Tables 44-63 describe the parameters
visible in the configuration view. Tables 64-89 describe the additional
calculated values seen in the commissioning view. Finally, Table 91
lists the input/output object attributes mapped to the Metasys Network.
VMA Single Duct Main View Parameters
Table 43: VMA Single Duct Main View Parameters
VMA Parameters
Configuration
Commissioning
Test and Balance
X
X
X
X
VAV Box Mode
Present Value
Occupancy Mode
Input
X
Schedule
X
X
Present Value
X
X
Temp Setpoints
Actual Cooling Setpt
X
Actual Heating Setpt
X
Common Setpoint
X
X
Cooling Setpoint
X
X
Heating Setpoint
X
X
Low Limit Temp Setpt
X
X
Setpoint Threshold
X
X
Low Setpoint Limit
X
X
High Setpoint Limit
X
X
TMZ Setpoint Range
Temp Biases
Actual Cooling Bias
X
Actual Heating Bias
X
Occupied Clg Bias
X
X
Standby Clg Bias
X
X
Unoccupied Clg Bias
X
X
Occupied Htg Bias
X
X
Standby Htg Bias
X
X
Unoccupied Htg Bias
X
X
Continued on next page . . .
90
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
VMA Parameters (Cont.)
Configuration
Commissioning
Test and Balance
Temp Diagnostics
MovAvg ZT Err
X
MovAvg ABS ZT Err
X
Inadequate Cooling
X
Inadequate Heating
X
Summer Winter Comp
Outdoor Air Temp
X
Summer Compensation
X
Winter Compensation
Summer Setpoint
X
X
X
Summer Authority
X
X
Summer Change Limit
X
X
Winter Setpoint
X
X
Winter Authority
X
X
Winter Change Limit
X
X
Flow Status
Present Value
X
Process Variable
X
X
Setpoint
X
X
Exhaust Flow Status
Present Value
X
Process Variable
X
X
Setpoint
X
X
Flow Setpoints
Cooling Flow SP
X
Heating Flow SP
X
X
Exhaust Diff
Cooling Max Flow
X
X
X
Occupied Clg Min
X
X
X
Unoccupied Clg Min
X
X
X
Occupied Htg Flow
X
X
X
Unoccupied Htg Flow
X
X
X
Heating Max Flow
X
X
X
Occupied Htg Min
X
X
X
Unoccupied Htg Min
X
X
X
Occupied Exh Diff
X
X
X
Unoccupied Exh Diff
X
X
X
Warmup Min Flow
X
X
X
Box Elec Htg Min Flo
X
X
X
Box Elec Htg Protect
X
X
X
Units
X
X
Continued on next page . . .
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
VMA Parameters (Cont.)
Configuration
Commissioning
Test and Balance
Flow Diagnostics
MovAvg Flow Err
X
MovAvg ABS Flow Err
X
Starved Box
X
MovAvg Exhst Err
X
MovAvg ABS Exhst Err
X
MovAvg Diff Err
X
MovAvg ABS Diff Err
X
Starved Exhaust Box
Units
X
X
X
Indoor Air Quality
IAQ Min Flow
X
OA Fraction
X
Occupancy Level
X
X
Ventilation Reqmnt
X
X
Supply Flow Config
Area
X
X
X
Pickup Gain
X
X
X
X
Flow Coefficient
X
X
Pvar Units
X
X
Delta Vp
X
X
Min Delta Vp
X
X
Max Velocity
X
X
Exhaust Flow Config
Area
X
X
X
Pickup Gain
X
X
X
X
Flow Coefficient
X
X
Pvar Units
X
X
Delta Vp
X
X
Min Delta Vp
X
X
Max Velocity
X
X
Supply Dpr Actuator
Reliability
X
Setup
X
Output
X
Present Value
X
Direction to Close
X
X
Polarity
X
X
Min Out Value
X
X
Max Out Value
X
X
Sply Dpr Stroke Time
X
X
PD Supply Max Pos
X
X
Startup Autorange
X
X
Autocal
Continued on next page . . .
X
91
92
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
VMA Parameters (Cont.)
Configuration
Commissioning
Test and Balance
Supply Dpr Actuator (Cont.)
Actuator Duty Cycle
X
MovAvg Sply Duty Cyc
X
MovAvg Sply Reversal
X
Exhaust Dpr Actuator
Reliability
X
Setup
X
Output
X
X
Present Value
Polarity
X
X
Min Out Value
X
X
Max Out Value
X
X
Exh Dpr Stroke Time
X
X
PD Exhaust Max Pos
X
X
MovAvg Exh Duty Cyc
X
MovAvg Exh Reversals
X
Command Modes
Heating Available
X
Water System Flush
X
X
Flush Position
X
X
Warmup Differential
X
X
Temp Loop Failsoft
X
X
X
Box Supply Temp
Autocalibration
Autocal Period
X
X
Autocal Time
X
Autocal Req
X
X
Autocal Active
X
X
X
X
On Pulse Count
X
Occupancy Timer
Present Value
X
Time Remaining
X
X
X
Light Shutoff Delay
X
X
Parallel Fan Min Flo
X
X
X
Fan Speed Percent
X
X
X
Duration
Lighting
X
Present Value
Fan Control
Cooling PID
Present Value
X
Process Variable
X
Setpoint
X
Saturation Status
X
Continued on next page . . .
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
VMA Parameters (Cont.)
Configuration
Commissioning
Box Heating PID
Present Value
X
Process Variable
X
Setpoint
X
Saturation Status
X
Box Heating Output
Object Type
X
Present Value
X
Actual Stage
X
Input
X
X
Output
Stroke Time
X
X
Polarity
X
X
Interstage Off Delay
X
Interstage On Delay
X
Make Limit
X
Break Limit
X
Min Off Limit
X
Min On Limit
X
Box Htg Make Lmt
X
X
Box Htg Diffrntl
X
X
Suppl Heating PID
Present Value
X
Process Variable
X
Setpoint
X
Saturation Status
X
Suppl Heating Output
Object Type
X
Present Value
X
Actual Stage
X
Input
X
Output
X
Stroke Time
X
X
Polarity
X
X
Interstage Off Delay
X
Interstage On Delay
X
Make Limit
X
Break Limit
X
Min Off Limit
X
Min On Limit
X
Suppl Htg Make Lmt
X
X
Suppl Htg Diffrntl
X
X
Continued on next page . . .
93
Test and Balance
94
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
VMA Parameters (Cont.)
Configuration
Commissioning
Test and Balance
Heating Flow PID
Present Value
X
Process Variable
X
Setpoint
X
Saturation Status
X
Sideloop PID
Present Value
X
Process Variable
X
Setpoint
X
Saturation Status
X
X
Offset
X
X
Deadband
X
X
Proportional Band
X
X
Integral Time
X
X
Self Tuning
X
X
Direct Acting
X
X
Period
X
X
Sideloop Output
Object Type
X
Present Value
X
Actual Stage
X
Input
X
X
Output
Stroke Time
X
X
Polarity
X
X
Interstage Off Delay
X
Interstage On Delay
X
Make Limit
X
Break Limit
X
Min Off Limit
X
Min On Limit
X
Sideloop Make Limit
X
X
Sideloop Diffrntl
X
X
X
X
RF Wireless Thermostat
Powerfail Diag
X
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
95
VMA Single Duct Configuration Parameters
Note:
An address entry of **** indicates that this parameter is not
mapped to an address.
Table 44: Occupancy Mode Parameters
Parameter Name
Address
Default
Description
Input
ADI 165
Occupied
0 - Unoccupied
1 - Standby
2 - Occupied
See the Key Concepts section for complete
description.
Table 45: Temperature Setpoints Parameters
Parameter Name
Address
Default
Description
Common Setpoint
ADF 197
21°C (70°F)
Primary supervisory zone temperature setpoint
Cooling Setpoint
ADF 189
0°C (0°F)
Zone temperature cooling setpoint (in place of
common setpoint)
Heating Setpoint
ADF 193
0°C (0°F)
Zone temperature heating setpoint (in place of
common setpoint)
Low Limit Temp Setpt
ADF 198
4°C (40°F)
Zone temperature setpoint during Low Limit mode
Setpoint Threshold
ADF 183
3°C (5°F)
Minimum temperature setpoint change required to
bypass saturation timers between modes. If Cooling
is active and the Actual Cooling Setpt increases by at
least the Setpoint Threshold, the mode immediately
switches to Satisfied. Similarly, if either Box Heating
or Supplemental Heating is active and the Actual
Heating Setpt decreases by at least the Setpoint
Threshold, the mode immediately switches to
Satisfied.
Table 46: TMZ Setpoint Range Parameters
Parameter Name
Address
Default
Description
Low Setpoint Limit
ADF 127
19°C (65°F)
TMZ low limit for Comfort Setpoint. The TMZ reads
this parameter from the VMA and prevents the
temperature setpoint from being adjusted below this
value.
High Setpoint Limit
ADF 128
26°C (78°F)
TMZ high limit for Comfort Setpoint. The TMZ reads
this parameter from the VMA and prevents the
temperature setpoint from being adjusted above this
value.
96
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Table 47: Temperature Biases Parameters
Parameter Name
Address
Default
Description
Occupied Clg Bias
ADF 190
1°C (2°F)
Occupied mode cooling bias temperature
Standby Clg Bias
ADF 191
3°C (5°F)
Standby mode cooling bias temperature
Unoccupied Clg Bias
ADF 192
4°C (8°F)
Unoccupied mode cooling bias temperature
Occupied Htg Bias
ADF 194
-1°C (-2°F)
Occupied mode heating bias temperature
Standby Htg Bias
ADF 195
-4°C (-6°F)
Standby mode heating bias temperature
Unoccupied Htg Bias
ADF 196
-5°C (-10°F)
Unoccupied mode heating bias temperature
Table 48: Summer Winter Comp. Parameters
Parameter Name
Address
Default
Description
Summer Setpoint
****
26°C (79°F)
Outdoor air temperature above which summer
compensation occurs
Summer Authority
****
0.2
Proportion of the change to setpoint to the difference
between outdoor air temperature and summer
setpoint
Summer Change Limit
****
5°C (9°F)
Maximum allowed setpoint change by summer
compensation
Winter Setpoint
****
10°C (50°F)
Outdoor air temperature below which winter
compensation occurs
Winter Authority
****
-0.1
Proportion of the change to setpoint to the difference
between outdoor air temperature and winter setpoint
Winter Change Limit
****
3°C (6°F)
Maximum allowed setpoint change by winter
compensation
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
97
Table 49: Flow Setpoints Parameters
Parameter Name
Address
Default
3
Description
Cooling Max Flow
ADF 163
850 m /hr
(500 cfm)
Maximum cooling flow setpoint
Occupied Clg Min
ADF 164
3
170 m /hr
(10 cfm)
Occupied mode cooling minimum flow setpoint
Unoccupied Clg Min
ADF 166
3
85 m /hr
(50 cfm)
Unoccupied mode cooling minimum flow setpoint
Occupied Htg Flow*
ADF 165
340 m /hr
(200 cfm)
Occupied mode heating flow setpoint
Unoccupied Htg Flow*
ADF 167
3
170 m /hr
(100 cfm)
Unoccupied mode heating flow setpoint
Heating Max Flow*
ADF 161
3
850 m /hr
(500 cfm)
Heating maximum flow (only w/ heating flow reset)
Occupied Htg Min*
ADF 165
3
340 m /hr
(200 cfm)
Occupied mode heating flow setpoint
(only w/ heating flow reset)
Unoccupied Htg Min*
ADF 167
170 m /hr
(100 cfm)
Unoccupied mode heating flow setpoint
(only w/ heating flow reset)
Occupied Exh Diff
ADF 206
3
340 m /hr
(200 cfm)
Occupied mode exhaust differential setpoint
Unoccupied Exh Diff
ADF 207
3
170 m /hr
(100 cfm)
Unoccupied mode exhaust differential setpoint
Warmup Min Flow
ADF 200
3
170 m /hr
(100 cfm)
Minimum box flow during Warmup mode
Box Elec Htg Min Flow
ADF 162
3
128 m /hr
(75 cfm)
Minimum flow requirement for EHS flow interlock, the
actual heating flow setpoint must be somewhat
greater so that minor flow deviations do not cause
the electric heat to chatter.
Box Elec Htg Protect
BD 170
False
When True, the Box Elec Htg Protect enables
minimum flow protection for Analog Output and
Duration Adjust Output box heating devices.
Units
****
m /hr
(cfm)
*
1
2
3
3
3
3
This allows change of the units for the above
Parameters.
Heating flow setpoints:
For VAV boxes with reheat but without fans, the heating flow setpoints must equal or be greater than
(for cfm): 400 times the flow area in sq ft, or (for m3/hr): 7315 times the flow area in m3.
If the zone/box schedule from the HVAC design does not call out both heating maximum and minimum
flow setpoints, the configuration question, “Increase box flow setpoint upon full heating?” must be
answered “No”. If no heating flow setpoint is given in the HVAC design, then the Occupied Heating Flow
setpoint should be set equal to the cooling minimum.
If the VAV box does not have a fan and heating is required in Unoccupied mode, then the Unoccupied
Heating Flow should equal the Occupied Heating Flow.
Table 50: Indoor Air Quality Parameters
Parameter Name
Address
Default
Occupancy Level
ADF 185
0 people
Normal zone occupancy level
Ventilation Reqmnt
****
3
34 m /hr
(20 cfm)
Zone ventilation requirement per person
Description
98
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Table 51: Supply Flow Configuration Parameters
Parameter
Name
Address
Default
Area
ADF 24
0.0325 m
2
(0.35 ft )
Pickup Gain
ADF 25
2.25 (2.25)
Airflow pickup gain
Flow Coefficient
ADF 26
4644 (4005)
Flow property (function of elevation) (Change metric
value to 1290 to compute liters per second [l/s].)
Pvar Units
****
3
m /hr (cfm)
This attribute allows changes to the flow controller
process variable’s units.
Delta Vp
****
0.03194 Pa
(1.282e-4 in. w.c.)
Change in velocity pressure for 1 bit A/D (0.03194 for
liters per seconds [l/s])
Min Delta Vp
****
12.45 Pa
(0.05 in. w.c.)
Minimum Vp for noise estimate (12.45 for liters per
second [l/s])
Max Velocity
****
58522 m/hr
(3200 ft/min)
Unit flow velocity (16243 for liters per second [l/s])
Description
2
Box inlet area. See the Airflow Measurement topic in
the Key Concepts, Theory of Operation section of
this document.
Table 52: Exhaust Flow Config Parameters
Parameter
Name
Address
Default
Area
ADF 21
0.0325 m
2
(0.35 ft )
Pickup Gain
ADF 22
2.25 (2.25)
Airflow pickup gain
Flow Coefficient
ADF 23
4544 (2005)
Flow property (function of elevation) (Change metric
value to 1290 to compute liters per second [l/s].)
Pvar Units
****
3
M /hr (cfm)
This attribute allows changes to the flow controller
process variable’s units.
Delta Vp
****
0.17003 Pa
(6.8376e4 in. w.c.)
Change in velocity pressure for 1 bit A/D [0.17003 Pa
for liters per second (l/s)]
Min Delta Vp
****
12.45 Pa
(0.05 in. w.c.)
Minimum Vp for noise estimate (12.45 for liters per
second [l/s])
Max Velocity
****
58522 m/hr
(3200 ft/min)
Unit flow velocity (1243 for liters per second [l/s])
Description
2
Exhaust box inlet area. See the Airflow Measurement
topic in the Key Concepts, Theory of Operation
section of this document.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
99
Table 53: Supply Dpr Actuator Parameters
Parameter Name
Address
Default
Description
Direction to Close
****
Clockwise
Direction that the integrated actuator should turn to
close damper
Polarity
****
Normal
For PAO output: 1st BO ON to open - normal;
first BO ON to close - reverse
Min Out Value
****
0%
For analog output, % of 10 volts at 0% control
Max Out Value
****
100%
For analog output, % of 10 volts at 100% control
Sply Dpr Stroke Time
****
90 seconds
Stroke time for AO output
PD Supply Max Pos
ADF 181
100%
Maximum position for supply actuator during
pressure dependent mode.
Startup Autorange
****
True
For integrated actuator, enables or disables
automatic calibration of actuator stroke time based
on measured stroke time. Normally occurs at first
autocalibration.
Table 54: Exhaust Dpr Actuator
Parameter Name
Address
Default
Description
Polarity
****
Normal
For PAO output: First BO ON to open – normal; first
BO ON to close - reverse
Min Out Value
****
0%
For analog output, % of 10 volts at 0% control
Max Out Value
****
100%
For analog output, % of 10 volts at 100% control
Exh Dpr Stroke Time
****
90 seconds
Stroke time for AO output
PD Exhaust Max Pos
ADF 182
100%
Maximum position for exhaust actuator during
pressure dependent mode.
Table 55: Command Modes Parameters
Parameter Name
Address
Default
Description
Water System Flush
****
False
Flag to command VMA into Water Flush mode
Flush Position
****
100
Heating valve position during Water Flush mode
Warmup Differential
****
8°C (15°F)
Differential for supply air temperature to initiate
warmup
Temp Loop Failsoft
****
Hold Outputs
Failsoft command when zone temperature AI is
unreliable. See the Temperature Loop topic in the
Key Concepts, Application Logic section of this
document.
Table 56: Autocalibration Parameters
Parameter Name
Address
Default
Description
Autocal Period
****
336 hours
Autocalibration period (hours between subsequent
autocalibrations)
On Pulse Count
ADF 170
3 seconds
For adjustment of the on-time for the BO solenoid air
valve, depending on the time needed to equalize the
dP pressure. The default value is sufficient for most
installations. To verify sufficient settling time,
compare the dP offset calculated during
autocalibration once with the damper open and once
when you override the damper closed.
100
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Table 57: Occupancy Timer Parameter
Parameter Name
Address
Default
Description
Duration
Occupancy Override
Time
****
60 minutes
Occupancy timer duration
ADF 85
60 minutes
Occupancy timer duration when mapped from the
supervisory system
Table 58: Lighting Parameter
Parameter Name
Address
Default
Description
Light Shutoff Delay
ADF 180
2 minutes
Time between light blink and complete light shutoff
when Occupancy mode transitions to unoccupied
Table 59: Fan Control Parameters
Parameter Name
Address
Default
Parallel Fan Min Flo
ADF 177
170m /hr
(100 cfm)
Flow-based parallel fan control parameter. If flow is
below this setpoint, fan is turned on.
Fan Speed Percent
ADF 178
100%
Series fan analog output parameter. Sets AO signal
(percent of 0-10 volts) to fan when on. Set by VAV
terminal manufacturer or Test and Balance
contractor.
3
Description
Table 60: Box Heating Output Parameters
Parameter Name
Address
Default
Description
Stroke Time
****
60 seconds
Stroke time for PAO output
Polarity
****
Normal
For PAO output: 1st BO ON to open - normal;
first BO ON to close - reverse
Polarity
****
Normal
For BO normally closed - normal;
BO normally open - reverse
Box Htg Make Lmt
****
55%
For BO object, output is active when input is above
this value.
Box Htg Differential
****
10%
For BO object, output changes from active to inactive
when input falls below make limit by this value.
Table 61: Suppl Heating Output Parameters
Parameter Name
Address
Default
Description
Stroke Time
****
60 seconds
Stroke time for PAO output
Polarity
****
Normal
For PAO output: first BO ON to open - normal;
first BO ON to close - reverse
Polarity
****
Normal
For BO normally closed - normal;
BO normally open - reverse
Suppl Htg Make Lmt
****
55%
For BO object, output is active when input is above
this value.
Suppl Htg Differential
****
10%
For BO object, output changes from active to inactive
when input falls below make limit by this value.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note 101
Table 62: Sideloop PID Parameters
Parameter Name
Address
Default
Description
Setpoint
Offset
ADF 199
0
Current setpoint for the sideloop control algorithm
****
0
Deadband
****
0
Proportional Band
****
10
Integral Time
****
300 seconds
Self Tuning
****
-
Direct Acting
****
True
Period
****
60 seconds
Flag designating whether PRAC is used
Time period between PID calculations
Table 63: Sideloop Output Parameters
Parameter Name
Address
Default
Description
Stroke Time
****
60 seconds
Stroke time for PAO output
Polarity
****
Normal
For PAO output
Polarity
****
-
BO normally closed - normal;
BO normally open - reverse
Sideloop Make Lmt
****
55%
For BO object, output is active when input is above
this value.
Sideloop Differential
****
10%
For BO object, output changes from active to inactive
when input falls below make limit by this value.
102
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
VMA Single Duct Commissioning Parameters
Note:
An address entry of **** indicates that this parameter is not
mapped to an address.
Table 64: VAV Box Mode Parameters
Parameter Name
Address
Description
Present Value
ADI 67
Primary VMA control mode.
Command modes:
Auto modes:
0 = Shutdown Closed
5 = Satisfied
1 = Shutdown Open
6 = Cooling
2 = Warmup
7 = Heating
3 = Water System Flush
4 = Low Limit
See the Key Concepts section for complete description.
Table 65: Occupancy Mode Parameters
Parameter Name
Address
Description
Schedule
ADI 78
0 – Unoccupied
1 – Standby
2 – Occupied
3 – No Schedule
This parameter provides a non-archivable point for scheduling
commands. If N2 communication fails, the Occupancy Mode Input
becomes the default mode. See the Key Concepts section for a
complete description.
Present Value
ADI 68
0 - Unoccupied
1 - Standby
2 - Occupied
See the Key Concepts section for complete description.
Table 66: Heating Mode Parameters
Parameter Name
Address
Description
Present Value
ADI 69
Primary heating control mode.
This point can be viewed from the diagnostic view.
0 = No Heating Required
1 = Box Heating
2 = Supplemental Heating with Full Box Heating
3 = Supplemental Heating
4 = Box Heating with Full Supplemental Heating
5 = Maximum Heating with Flow Reset
See the Key Concepts section for complete description.
Table 67: Temperature Setpoints Parameters
Parameter Name
Address
Description
Actual Cooling Setpt
ADF 13
Actual Clg SP = Common SP + Remote Adjustment + Clg SP + Actual
Clg Bias + Summer Compensation
Actual Heating Setpt
ADF 14
Actual Htg SP = Common SP + Remote Adjustment + Htg SP +
Actual Htg Bias + Winter Compensation
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note 103
Table 68: Temperature Biases Parameters
Parameter Name
Address
Description
Actual Cooling Bias
ADF 15
Actual Cooling Bias = specified cooling bias of the current Occupancy
Mode Present Value
Actual Heating Bias
ADF 16
Actual Heating Bias = specified heating bias of current Occupancy
Mode Present Value
Table 69: Temperature Diagnostics Parameters
Parameter Name
Address
Description
MovAvg ZT Err
ADF 6
Moving average of the error between the current zone temperature
and the zone temperature setpoint
MovAvg ABS ZT Err
ADF 7
Moving average of the absolute value of the zone temperature error
Inadequate Cooling
BD 3
True when box is unable to maintain the zone at the cooling
temperature setpoint and is not starved for flow
Inadequate Heating
BD 4
True when all available heat is at maximum, but the box is unable to
maintain the zone at the heating setpoint
Table 70: Summer Winter Comp. Parameters
Parameter Name
Address
Description
Outdoor Air Temp
ADF 81
Outdoor air temperature value provided via network
Summer
Compensation
ADF 17
Summer Comp. = min (Summer Change Limit, Summer Authority
[SummerSP – OutdoorAir])
Winter Compensation
ADF 18
Winter Comp. = - min. (Winter Change Limit, Winter Authority
[WinterSP - OutdoorAir])
Table 71: Flow Status Parameters
Parameter Name
Address
Description
Present Value
****
Output of the P-Adaptive control algorithm. See the Key Concepts
section for more information.
Process Variable
ADF 58
Current flowrate being delivered by box
Setpoint
ADF 150
Current setpoint for box flow (based on Cooling or Heating Flow PIDs)
Table 72: Exhaust Flow Status
Parameter Name
Address
Description
Present Value
*****
Output of the P-Adaptive control algorithm. See the Key Concepts
section for more information.
Process Variable
ADF 59
Current flowrate being removed by the exhaust box
Setpoint
ADF 151
Current setpoint for exhaust flow (based on the supply setpoint and
the exhaust differential)
104
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Table 73: Flow Setpoints Parameters
Parameter Name
Address
Description
Cooling Flow SP
****
Calculated based upon the Cooling PID output and the cooling min
(based on occupancy) and max flow SPs
Exhaust Differential
****
Current exhaust differential based on Occupancy mode
Heating Flow SP
****
Normally equal to the heating flow setpoint corresponding to the
current Occupancy mode
Table 74: Flow Diagnostics Parameters
Parameter Name
Address
Description
MovAvg Flow Err
ADF 8
Moving average of the error between the actual flow and the current
flow setpoint
MovAvg ABS Flow Err
ADF 9
Moving average of the absolute value of the flow error
Starved Box
BD 55
True if the box is unable to maintain the flow setpoint
(that is, damper remains saturated at 100% open)
MovAvg Exhst Err
ADF 43
Moving average of the error between the actual exhaust flow and the
current exhaust flow setpoint
MovAvg ABS Exhst
Err
ADF 44
Moving average of the absolute value of the exhaust flow error
MovAvg Diff Err
ADF 61
Moving average of the error between the actual exhaust differential
and the current exhaust differential error
MovAvg ABS Diff Err
ADF 62
Moving average of the absolute value of the exhaust differential error
Starved Exhaust Box
BD54
True if the exhaust box is unable to maintain the flow setpoint
(that is, damper remains saturated at 100% open)
Units
****
This attribute allows changes to the above attribute’s units.
Table 75: Indoor Air Quality Parameters
Parameter Name
Address
Description
IAQ Min Flow
****
IAQ Min Flow = Occupancy Level * Ventilation Requirement/OA
Fraction
OA Fraction
ADF 80
Percent outdoor air included in supply. Value must be mapped via a
network variable.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note 105
Table 76: Supply Damper Actuator Parameters
Parameter Name
Address
Description
Reliability
ADI 19
Reliability of the value or the reason for not being trustworthy if
unreliable
Setup
****
Actuator type
Output
ADF 54
Estimated position (0-100%) of the damper actuator
Present Value
ADF 152
The current command to the actuator
Direction to Close
****
Direction that actuator should turn to close damper
Autocal
****
SMO calibration command
Actuator Duty Cycle
ADF 4
Time that the actuator runs as a percent of the controller run time
MovAvg Sply Duty
Cyc
ADF 46
Moving average of the actuator duty cycle over the past 24 hours
MovAvg Sply Reversal
ADF 47
Moving average of the hourly reversals over the past 24 hours
Table 77: Exhaust Damper Actuator Parameters
Parameter Name
Address
Description
Reliability
ADI 18
Reliability of the value or the reason for not being trustworthy if
unreliable
Setup
****
Actuator type
Output
ADF 60
Estimated position (0-100%) of the damper actuator
Present Value
ADF 153
The current command to the actuator
MovAvg Exh Duty Cyc
ADF 49
Moving average of the actuator duty cycle over the past 24 hours
MovAvg Exh
Reversals
ADF 48
Moving average of the hourly reversals over the past 24 hours
Table 78: Command Modes Parameters
Parameter Name
Address
Description
Heating Available
BD 169
Used to specify when heating source is available (for example, boiler
and hot water pumps on)
Box Supply Temp
ADF 82
Box supply temperature mapped via network variable (used instead of
individual hardware input to VMA)
Table 79: Autocalibration Parameters
Parameter Name
Address
Description
Autocal Time
****
Current number of hours since most previous autocalibration
Autocal Req
BD 168
Flag used to request an autocalibration
Autocal Active
BD 66
Status of the autocalibration routine
Table 80: Occupancy Timer Parameters
Parameter Name
Address
Description
Present Value
BD 12
Status of the occupancy timer
Time Remaining
****
Time remaining in the current temporary occupancy period (if active)
106
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Table 81: Lighting Parameters
Parameter Name
Address
Description
Present Value
ADI 65
Status of lighting control
Table 82: Cooling PID Parameters
Parameter Name
Address
Description
Present Value
ADF 70
Output of the PID control algorithm
Process Variable
****
Current zone temperature
Setpoint
****
Current zone temperature cooling setpoint
Saturation Status
****
ADF 30*
ADF 31*
Low (High) if output of PID remains 0.0 (100.0) for saturation time
Proportional band
Integral time
*
This parameter can only be adjusted by PRAC. If mapped over the N2, it is a monitor only point.
Table 83: Box Heating PID Parameters
Parameter Name
Address
Description
Present Value
ADF 72
Output of the PID control algorithm
Process Variable
****
Current zone temperature
Setpoint
****
Current zone temperature heating setpoint
Saturation Status
****
Low (High) if output of PID remains 0.0 (100.0) for saturation time
ADF 32*
Proportional band
ADF 33*
Integral time
*
This parameter can only be adjusted by PRAC. If mapped over the N2, it is a monitor only point.
Table 84: Box Heating Output Parameters
Parameter Name
Address
Description
Object Type
****
Standard output object type selected (for example, BO, PAO, AO,
DAO, EHS)
Present Value
ADI or
ADF 140
The current output command
Actual Stage
ADI 2
For an EHS object, the actual stages active (different from present
value due to min flow and stage timing)
Input
ADF 50
Input signal from Box Heating PID output
Output
ADF 51
Estimated position of a PAO object
Interstage Off Delay
****
Delay between turning off subsequent EHS stages
Interstage On Delay
****
Delay between turning on subsequent EHS stages
Make Limit
****
Make limit (or limits) for EHS objects
Break Limit
****
Break limit (or limits) for EHS objects
Min Off Limit
****
Above this value, a DAO object remains on at 100%.
Min On Limit
****
Below this value, a DAO object remains off at 0%.
Box Htg Make Lmt
****
For BO object, output is active when input is above this value.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note 107
Table 85: Suppl Heating PID Parameters
Description
Parameter Name
Address
Present Value
ADF 73
Output of the PID control algorithm
Process Variable
****
Current zone temperature
Setpoint
****
Current zone temperature heating setpoint
Saturation Status
****
Low (High) if output of PID remains 0.0 (100.0) for saturation time
Table 86: Suppl Heating Output Parameters
Parameter Name
Address
Description
Object Type
****
Standard output object type selected (for example, BO, PAO, AO,
DAO, EHS)
Present Value
ADI or
ADF 141
The current output command
Actual Stage
ADI 6
For an EHS object, the actual stages active (different from present
value due to min flow and stage timing)
Input
ADF 52
Input signal from Supplemental Heating PID output
Output
ADF 53
Estimated position of a PAO object
Interstage Off Delay
****
Delay between turning off subsequent EHS stages
Interstage On Delay
****
Delay between turning on subsequent EHS stages
Make Limit
****
Make limit (or limits) for EHS objects
Break Limit
****
Break limit (or limits) for EHS objects
Min Off Limit
****
Above this value, a DAO object remains on at 100%.
Min On Limit
****
Below this value, a DAO object remains off at 0%.
Table 87: Heating Flow PID Parameters
Parameter Name
Address
Description
Present Value
ADF 71
Output of the PID control algorithm. Changes flow setpoint during
heating if heating flow reset is enabled.
Process Variable
****
Current zone temperature
Setpoint
****
Current zone temperature heating setpoint
Saturation Status
****
Low (High) if output of PID remains 0.0 (100.0) for saturation time
Table 88: Sideloop PID Parameters
Parameter Name
Address
Description
Present Value
****
Output of the PID control algorithm
Process Variable
****
Current value of the input sensor
Saturation Status
****
Low (High) if output of PID remains 0.0 (100.0) for saturation time
108
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Table 89: Sideloop Output Parameters
Parameter Name
Address
Description
Object Type
****
Standard output object type selected (for example, BO, PAO, AO,
DAO, EHS)
Present Value
ADI or
ADF 142
The current output command
Actual Stage
ADI 31
For an EHS object, the actual stages active (different from present
value due to min flow and stage timing)
Input
ADF 55
Input signal from Sideloop PID output
Output
ADF 56
Estimated position of a PAO object
Interstage Off Delay
****
Delay between turning off subsequent EHS stages
Interstage On Delay
****
Delay between turning on subsequent EHS stages
Make Limit
****
Make limit (or limits) for EHS objects
Break Limit
****
Break limit (or limits) for EHS objects
Min Off Limit
****
Above this value, a DAO object remains on at 100%.
Min On Limit
****
Below this value, a DAO object remains off at 0%.
Table 90: RF Wireless Thermostat
Parameter Name
Address
Description
Powerfail Diag
BD 180
TE7710 low battery indicator
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note 109
VMA Single Duct Mapped Input/Output Attributes
The general characteristics of each of the input and output options
available for use in VMA applications, as well as a detailed description
of each of the viewable attributes, are given in the Input/Output
Options topic in this section. Table 91 lists the attributes that are
mapped to the Metasys Network for the inputs and outputs of the
VMA single duct application.
Table 91: VMA Single Duct Application Input and Output Attributes Mapped to the
Metasys Network
Attribute
Short Name
Long Name
Address
ZN-T
Present Value
AI n
ZTREL
Reliability
ADI 20
Zone Temperature (AI)
Remote Adjust (AI)
W-C-ADJ
Present Value
AI n
RAREL
Reliability
ADI 21
REM-SET
Present Value
AI n
RSREL
Reliability
ADI 22
Remote Setpoint (AI)
Box Supply Temp (AI)
BOXS-T
Present Value
AI n
BSTREL
Reliability
ADI 24
S-VP
Present Value
AI n
DPREL
Reliability
ADI 23
Supply Delta P (AI)
Exhaust Delta P (AI)
E-VP
Present Value
AI n
EDPREL
Reliability
ADI 26
SLAI
Present Value
AI n
SLIREL
Reliability
ADI 25
Sideloop Input (AI)
Occupancy Button (BI)
TEMP-OCC
Present Value
BI n
OCCCNREL
Reliability
ADI 10
OCC-S
Present Value
BI n
OCCSNREL
Reliability
ADI 9
Occupancy Sensor (BI)
Low Limit Contact (BI)
Continued on next page . . .
LT-ALM
Present Value
BI n
LLCNREL
Reliability
ADI 11
110
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Attribute (Cont.)
Short Name
Long Name
Address
BOXHTG
Present Value (PAO, DAO)
ADF 140
BOXHTG
Present Value (AO)
AO n
BOXHTG-C
Present Value (BO)
BO n
BOXHTG
Present Value (EHS)
ADI 140
BHOUTPUT
Output (PAO, AO, DAO, EHS)
ADF 51
BHOUTPUT
Output (BO)
ADI 51
BHREL
Reliability
ADI 1
Box Heating Cmd (PAO, AO, DAO, BO, EHS)
BHACTSTG
Actual Stage (EHS)
ADI 2
BHINPUT
Input (EHS)
ADF 50
BHINSOFF
Instant All Off (EHS)
BD 41
RADHTG
Present Value (PAO, DAO)
ADF 141
RADHTG
Present Value (AO)
AO n
RADHTG-C
Present Value (BO)
BO n
RADHTG
Present Value (EHS)
ADI 141
Suppl Heating Cmd (PAO, AO, DAO, BO, EHS)
SHOUTPUT
Output (PAO, AO, DAO, EHS)
ADF 53
SHOUTPUT
Output (BO)
ADI 53
SHREL
Reliability
ADI 5
SHACTSTG
Actual Stage (EHS)
ADI 6
SHINPUT
Input (EHS)
ADF 52
SHINSOFF
Instant All Off (EHS)
BD 43
SER-FAN
Present Value (AO)
AO n
Series Fan (AO, BO)
SER-F-C
Present Value (BO)
BO n
FANREL
Reliability
ADI 15
PAR-F-C
Present Value
BO n
FANREL
Reliability
ADI 15
DMPRPV
Present Value (SMO, PAO)
ADF 152
DPR-C
Present Value (AO)
AO n
DMPRPOS
Output
ADF 54
DMPRREL
Reliability
ADI 19
Present Value (PAO)
ADF 153
Parallel Fan (BO)
Damper Cmd (SMO, PAO, AO)
Exhaust Damper Cmd (PAO, AO)
EDPRPV
EDPR-C
Present Value (AO)
AO n
EDPRPOS
Output
ADF 60
DDPRREL
Reliability
ADF 18
Lights
Continued on next page . . .
LTG-C
Present Value
ADI 65
LGHTREL
Reliability (SSO)
ADI 16
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note 111
Attribute (Cont.)
Short Name
Long Name
Address
Present Value (PAO, DAO)
ADF 142
Sideloop Cmd (PAO, AO, DAO, BO, EHS)
SLPAO, SLDAO
SLAO, SLBO
Present Value (AO, BO)
AO n, BO n
SLEHS
Present Value (EHS)
ADI 142
SLOUTPUT
Output (PAO, AO, DAO, EHS)
ADF 56
SLOUTPUT
Output (BO)
ADI 56
SLCREL
Reliability
ADI 30
SLACTSTG
Actual Stage (EHS)
ADI 31
SLINPUT
Input (EHS)
ADI 55
SLINSOFF
Instant All Off (EHS)
BD 45
VMA Dual Duct Parameters
The VMA has adjustable parameters, but most do not require changes.
Changing parameters may cause the controller to malfunction. We
offer this document to provide a reference for the application
parameters used to configure VMA dual duct application.
This topic has four groups of tables. Table 92 shows which parameters
are in each of the main views. Tables 93-114 describe the parameters
visible in the configuration view. Tables 115-137 describe the
additional calculated values seen in the commissioning view. Finally,
Table 138 lists the input/output object attributes mapped to the
Metasys Network.
112
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
VMA Dual Duct Main View Parameters
Table 92: VMA Dual Duct Main View Parameters
VMA Parameters
Configuration
Commissioning
Test and Balance
X
X
X
X
VAV Box Mode
Present Value
Occupancy Mode
Input
X
Schedule
X
X
Present Value
X
X
Cold Deck Available
X
X
Hot Deck Available
X
X
Command Modes
Cold Deck Percent
X
Hot Deck Percent
X
Warmup Req
X
X
Cooldown Req
X
X
Low Limit Req
X
X
Suppl Htg Available
X
X
Water System Flush
X
X
X
Flush Position
X
X
Temp Loop Failsoft
X
X
Temp Setpoints
Actual Cooling Setpt
X
Actual Heating Setpt
X
Common Setpoint
X
X
Cooling Setpoint
X
X
Heating Setpoint
X
X
Low Limit Temp Setpt
X
X
Discharge Temp Limit
X
X
Low Setpoint Limit
X
X
High Setpoint Limit
X
X
TMZ Setpoint Range
Temp Biases
Actual Cooling Bias
X
Actual Heating Bias
X
Occupied Clg Bias
X
X
Standby Clg Bias
X
X
Unoccupied Clg Bias
X
X
Occupied Htg Bias
X
X
Standby Htg Bias
X
X
Unoccupied Htg Bias
X
X
Continued on next page . . .
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note 113
VMA Parameters (Cont.)
Configuration
Commissioning
Test and Balance
Temp Diagnostics
MovAvg ZT Err
X
MovAvg ABS ZT Err
X
Inadequate Cooling
X
Inadequate Heating
X
Summer Winter Comp
Outdoor Air Temp
X
Summer Compensation
X
Winter Compensation
Summer Setpoint
X
X
X
Summer Authority
X
X
Summer Change Limit
X
X
Winter Setpoint
X
X
Winter Authority
X
X
Winter Change Limit
X
X
Deck Temperatures
Cold Deck Air Temp
X
X
Hot Deck Air Temp
X
X
Cold Deck Low Limit
X
X
Hot Deck High Limit
X
X
Min dP Velocity
X
X
Cold Deck Status
Present Value
X
Cold Deck Flow
X
X
Setpoint
X
X
Hot Deck Status
Present Value
X
Hot Deck Flow
X
X
Setpoint
X
X
Total Flow Status
Present Value
X
Total Flow
X
X
Setpoint
X
X
Continued on next page . . .
114
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
VMA Parameters (Cont.)
Configuration
Commissioning
Test and Balance
Cooling Max Flow
X
X
X
Heating Max Flow
X
X
X
Occ Box Min
X
X
X
Occ Cold Deck Min
X
X
X
Occ Hot Deck Min
X
X
X
Unocc Box Min
X
X
X
Unocc Cold Deck Min
X
X
X
Unocc Hot Deck Min
X
X
X
Warmup HD Min
X
X
X
Flow Setpoints
Warmup CD Flow
X
X
X
Cooldown CD Min
X
X
X
Cooldown HD Flow
X
X
X
Flow Units
Units
X
X
X
Pvar Units
X
X
X
Indoor Air Quality
CD OA Percent
X
HD OA Percent
X
CD IAQ Min Flow
X
HD IAQ Min Flow
X
Occupancy Level
X
X
Ventilation Reqmnt
X
X
Flow Diagnostics
MovAvg CD Err
X
MovAvg ABS CD Err
X
MovAvg HD Err
X
MovAvg ABS HD Err
X
MovAvg Total Err
X
MovAvg ABS Total Err
X
Starved Cold Deck
X
Starved Hot Deck
X
Cold Deck Config
Area
X
X
X
Pickup Gain
X
X
X
Flow Coefficient
X
X
X
Pvar Units
X
X
Delta Vp
X
X
Min Delta Vp
X
X
Max Velocity
X
X
Continued on next page . . .
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note 115
VMA Parameters (Cont.)
Configuration
Commissioning
Test and Balance
X
X
X
Hot Deck Config
Area
Pickup Gain
X
X
X
Flow Coefficient
X
X
X
Pvar Units
X
X
Delta Vp
X
X
Min Delta Vp
X
X
Max Velocity
X
X
X
X
Total Deck Config
Area
X
Pickup Gain
X
X
X
Flow Coefficient
X
X
X
Pvar Units
X
X
Delta Vp
X
X
Min Delta Vp
X
X
Max Velocity
X
X
Cold Deck Actuator
Reliability
X
Setup
X
Output
X
X
Present Value
Direction to Close
X
X
Polarity
X
X
Min Out Value
X
X
Max Out Value
X
X
X
Autocal
CD Stroke Time
X
X
Startup Autorange
X
X
Hot Deck Actuator
Reliability
X
Setup
X
Output
X
Present Value
X
Direction to Close
X
X
Polarity
X
X
Min Out Value
X
X
Max Out Value
X
X
HD Stroke Time
X
X
Continued on next page . . .
116
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
VMA Parameters (Cont.)
Configuration
Commissioning
Test and Balance
Actuator Diagnostics
MovAvg CD Reversals
X
MovAvg CD Duty Cycle
X
MovAvg HD Reversals
X
MovAvg HD Duty Cycle
X
Autocalibration
Autocal Period
X
X
Autocal Time
X
Autocal Req
X
X
Autocal Active
X
X
Occupancy Timer
Present Value
X
Time Remaining
Duration
X
X
X
Lighting
Present Value
Light Shutoff Delay
X
X
X
Energy Balance PID
Q Convert
Qdot Setpoint
X
X
X
Process Variable
X
Setpoint
X
High Limit
X
Present Value
X
Low Limit
X
Saturation Status
X
Suppl Heating PID
Present Value
X
Process Variable
X
Setpoint
X
Saturation Status
X
Continued on next page . . .
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note 117
VMA Parameters (Cont.)
Configuration
Commissioning
Suppl Heating Output
Object Type
X
Present Value
X
Actual Stage
X
Input
X
Output
X
Stroke Time
X
X
Polarity
X
X
Interstage Off Delay
X
Interstage On Delay
X
Make Limit
X
Break Limit
X
Min Off Limit
X
Min On Limit
X
Suppl Htg Make Lmt
X
X
Suppl Htg Diffrntl
X
X
Sideloop PID
Present Value
X
Process Variable
Setpoint
X
X
X
X
X
Saturation Status
Offset
X
Deadband
X
X
Proportional Band
X
X
Integral Time
X
X
Self Tuning
X
X
Direct Acting
X
X
Period
X
X
Sideloop Output
Object Type
X
Present Value
X
Actual Stage
X
Input
X
Output
X
Stroke Time
X
X
Polarity
X
X
Interstage Off Delay
X
Interstage On Delay
X
Make Limit
X
Break Limit
X
Min Off Limit
X
Min On Limit
X
Sideloop Make Limit
X
X
Sideloop Diffrntl
X
X
Test and Balance
118
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
VMA Dual Duct Configuration Parameters
Note:
An address entry of **** indicates that this parameter is not
mapped to an address.
Table 93: Occupancy Mode Parameters
Parameter Name
Address
Default
Description
Input
ADI 165
Occupied
0 – Unoccupied
1 – Standby
2 – Occupied
See the Key Concepts section for complete
description.
Table 94: Command Modes Parameters
Parameter Name
Address
Default
Description
Water System Flush
Flush Position
****
False
Flag to command VMA into Water Flush mode
****
100
Heating valve position during Water Flush mode
Temp Loop Failsoft
****
Hold Outputs
Failsoft command when zone temperature AI is
unreliable. See the Temperature Loop topic in the
Key Concepts, Application Logic section of this
document.
Table 95: Temperature Setpoints Parameters
Parameter Name
Address
Default
Description
Common Setpoint
ADF 197
21°C (70°F)
Primary supervisory zone temperature setpoint
Cooling Setpoint
ADF 189
0°C (0°F)
Zone temperature cooling setpoint
(in place of common setpoint)
Heating Setpoint
ADF 193
0°C (0°F)
Zone temperature heating setpoint
(in place of common setpoint)
Low Limit Temp Setpt
ADF 198
4°C (40°F)
Zone temperature setpoint during Low Limit mode
Discharge Temp Limit
ADF 188
0°C (32°F)
Minimum limit for discharge air temperature
Table 96: TMZ Setpoint Range Parameters
Parameter Name
Address
Default
Description
Low Setpoint Limit
ADF 127
19°C (65°F)
TMZ low limit for Comfort Setpoint. The TMZ reads
this parameter from the VMA and prevents the
temperature setpoint from being adjusted below this
value.
High Setpoint Limit
ADF 128
26°C (78°F)
TMZ high limit for Comfort Setpoint. The TMZ reads
this parameter from the VMA and prevents the
temperature setpoint from being adjusted above this
value.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note 119
Table 97: Temperature Biases Parameters
Parameter Name
Address
Default
Description
Occupied Clg Bias
ADF 190
0°C (0°F)
Occupied mode cooling bias temperature
Standby Clg Bias
ADF 191
2°C (4°F)
Standby mode cooling bias temperature
Unoccupied Clg Bias
ADF 192
4°C (8°F)
Unoccupied mode cooling bias temperature
Occupied Htg Bias
ADF 194
0°C (0°F)
Occupied mode heating bias temperature
Standby Htg Bias
ADF 195
-2°C (-4°F)
Standby mode heating bias temperature
Unoccupied Htg Bias
ADF 196
-4°C (-8°F)
Unoccupied mode heating bias temperature
Table 98: Summer Winter Comp. Parameters
Parameter Name
Address
Default
Description
Summer Setpoint
****
26°C (79°F)
Outdoor air temperature above which summer
compensation occurs
Summer Authority
****
0.2
Proportion of the change to setpoint to the difference
between outdoor air temperature and summer
setpoint
Summer Change Limit
****
5°C (9°F)
Maximum allowed setpoint change by summer
compensation
Winter Setpoint
****
10°C (50°F)
Outdoor air temperature below which winter
compensation occurs
Winter Authority
****
-0.1
Proportion of the change to setpoint to the difference
between outdoor air temperature and winter setpoint
Winter Change Limit
****
3°C (6°F)
Maximum allowed setpoint change by winter
compensation
Table 99: Deck Temperatures Parameters
Parameter Name
Address
Default
Description
Cold Deck Air Temp
ADF 185
13°C (55°F)
Configured cold deck temperature (no D.A.T. sensor)
or initial value for deck temperature estimate
calculation (D.A.T. sensor)
Hot Deck Air Temp
ADF 186
32°C (90°F)
Configured hot deck temperature (no D.A.T. sensor)
or initial value for deck temperature estimate
calculation (D.A.T. sensor)
Cold Deck Low Limit
****
0°C (32°F)
Minimum limit for cold deck temperature estimate
(D.A.T. sensor)
Hot Deck High Limit
****
60°C (140°F)
Maximum limit for hot deck temperature estimate
(D.A.T. sensor)
Min dP Velocity
****
7300 m/hr
(400 ft/min)
Minimum velocity for accurate dP measurement
(2030 for liters per second [l/s])
120
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Table 100: Flow Setpoints Parameters
Parameter Name
Address
Default
3
Description
Cooling Max Flow
ADF 161
850 m /hr
(500 cfm)
Maximum box (total) flow when application is at full
cooling, corresponding to control index 4
Heating Max Flow
ADF 162
3
850 m /hr
(500 cfm)
Maximum box (total) flow when application is at full
heating, corresponding to control index 1
Occ Box Min
ADF 163
3
850 m /hr
(500 cfm)
Occupied minimum box (total) flow. For variable
volume applications, the default is equal to 510 m3/hr
(300 cfm).
Occ Cold Deck Min
ADF 164
3
170 m /hr
(100 cfm)
Occupied minimum cold deck (individual) flow
setpoint
Occ Hot Deck Min
ADF 165
3
170 m /hr
(100 cfm)
Occupied minimum hot deck (individual) flow setpoint
Unocc Box Min
ADF 168
3
0 m /hr
(0 cfm)
Unoccupied minimum box (total) flow
Unocc Cold Deck Min
ADF 169
3
0 m /hr
(0 cfm)
Unoccupied minimum cold deck (individual) flow
setpoint
Unocc Hot Deck Min
ADF 170
3
0 m /hr
(0 cfm)
Unoccupied minimum hot deck (individual) flow
setpoint
Warmup HD Min
ADF 171
3
170 m /hr
(100 cfm)
Minimum hot deck (individual) flow during Warmup
mode
Warmup CD Flow
ADF 173
3
0 m /hr
(0 cfm)
Constant flow setpoint for cold deck (individual)
during Warmup mode
Cooldown CD Min
ADF 172
3
170 m /hr
(100 cfm)
Minimum cold deck (individual) flow during Cooldown
mode
Cooldown HD Flow
ADF 174
3
0 m /hr
(0 cfm)
Constant flow setpoint for hot deck (individual) during
Cooldown mode
Table 101: Flow Units Parameters
Parameter Name
Address
Default
Description
Units
****
3
m /hr (cfm)
This allows change of the display units for the flow
setpoints.
Pvar Units
****
3
m /hr (cfm)
This allows change of the display units for the flow
controllers.
Table 102: Indoor Air Quality Parameters
Parameter Name
Address
Default
Description
Occupancy Level
ADF 175
0 people
Normal zone occupancy level
Ventilation Reqmnt
****
3
34 m /hr
(20 cfm)
Zone ventilation requirement per person
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note 121
Table 103: Cold Deck Config Parameters
Parameter Name
Address
Default
Description
2
Area
ADF 11
Pickup Gain
ADF 12
2.25 (2.25)
Airflow pickup gain
Flow Coefficient
ADF 13
4644 (4005)
Flow property (function of elevation) (Change value
to 1290 to compute liters per second [l/s].)
Pvar Units
****
m /hr (cfm)
This attribute allows changes to the flow controller
process variable’s units.
Delta Vp
****
0.031936 Pa
(1.282e-4 in.
w.c.)
Change in velocity pressure for 1 bit A/D
(0.031936 for liters per seconds [l/s])
Min Delta Vp
****
12.45 Pa
(0.05 in. w.c.)
Minimum Vp for noise estimate
(12.45 for liters per second [l/s])
Max Velocity
****
58522 m/hr
(3200 ft/min)
Unit flow velocity (16243 for liters per second [l/s])
0.0325 m
(0.35 f2)
3
Box inlet area. See Airflow Measurement topic in the
Key Concepts, Theory of Operation section.
Table 104: Hot Deck Config Parameters
Parameter Name
Address
Default
Area
ADF 14
0.0325 m
(0.35 ft2)
Description
Pickup Gain
ADF 15
2.25 (2.25)
Airflow pickup gain
Flow Coefficient
ADF 16
4644 (4005)
Flow property (function of elevation) (Change value
to 1290 to compute liters per second [l/s].)
Pvar Units
****
3
m /hr (cfm)
This attribute allows changes to the flow controller
process variable’s units.
Delta Vp
****
0.17003 Pa
(6.8376e-4 in.
w.c.)
Change in velocity pressure for 1 bit A/D
[0.17003 for liters per seconds (l/s)]
Min Delta Vp
****
12.45 Pa
(0.05 in. w.c.)
Minimum Vp for noise estimate
(12.45 for liters per second [l/s])
Max Velocity
****
58522 m/hr
(3200 ft/min)
Unit flow velocity (16243 for liters per second [l/s])
2
Box inlet area. See the Airflow Measurement topic in
the Key Concepts section.
122
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Table 105: Total Deck Config Parameters
Parameter Name
Address
Default
2
Description
Area
ADF 17
0.0325
(0.35 f2)
Box inlet area. See the Airflow Measurement topic in
the Key Concepts section.
Pickup Gain
ADF 18
2.25 (2.25)
Airflow pickup gain
Flow Coefficient
ADF 19
4644 (4005)
Flow property (function of elevation) (Change value
to 1290 to compute liters per second [l/s].)
Pvar Units
****
m /hr (cfm)
This attribute allows changes to the flow controller
process variable’s units.
Delta Vp
****
****
Change in velocity pressure for 1 bit A/D. For internal
total flow dP sensor paired with hot deck external
sensor, default value is the same as for the cold
deck. Otherwise, the default is the same as for the
hot deck.
Min Delta Vp
****
12.45 Pa
(0.05 in. w.c.)
Minimum Vp for noise estimate
(12.45 for liters per second [l/s])
Max Velocity
****
58522 m/hr
(3200 ft/min)
Unit flow velocity (16243 for liters per second [l/s])
3
Table 106: Cold Deck Actuator Parameters
Parameter Name
Address
Default
Description
Direction to Close
****
Clockwise
Direction that the integrated actuator should turn to
close damper
Polarity
****
Normal
For PAO output: Normal - First BO ON to open;
Reverse - First BO ON to close
Min Out Value
****
0%
For analog output, % of 10 volts at 0% control
Max Out Value
****
100%
For analog output, % of 10 volts at 100% control
CD Stroke Time
****
90 seconds
Stroke time for AO output
Startup Autorange
****
True
For integrated actuator, enables or disables
automatic calibration of actuator stroke time based
on measured stroke time. Normally occurs at first
autocalibration.
Table 107: Hot Deck Actuator Parameters
Parameter Name
Address
Default
Description
Polarity
****
Normal
For PAO output: Normal - First BO ON to open;
Reverse - First BO ON to close
Min Out Value
****
0%
For analog output, % of 10 volts at 0% control
Max Out Value
****
100%
For analog output, % of 10 volts at 100% control
HD Stroke Time
****
90 seconds
Stroke time for AO output
Table 108: Autocalibration Parameters
Parameter Name
Address
Default
Description
Autocal Period
****
336 hours
Autocalibration period (hours between subsequent
autocalibrations)
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note 123
Table 109: Occupancy Timer Parameter
Default
Description
****
60 minutes
Occupancy timer duration
ADF 85
60 minutes
Occupancy timer duration when mapped from the
supervisory system
Parameter Name
Address
Duration
Occupancy Override
Time
Table 110: Lighting Parameter
Parameter Name
Address
Default
Description
Light Shutoff Delay
ADF 180
2 minutes
Time between light blink and complete light shutoff
when Occupancy mode transitions to unoccupied
Table 111: Energy Balance PID Parameter
Parameter Name
Address
Default
Description
Q Convert
****
1.1435 (1.08)
Conversion factor from product of temperature
difference and flow (4.119 for l/s and °C,
1.944 for cfm and °C). See the VMA Dual Duct
Applications topic in the Key Concepts section for
more details.
Table 112: Suppl Heating Output Parameters
Parameter Name
Address
Default
Description
Stroke Time
****
60 seconds
Stroke time for PAO output
Polarity
****
Normal
For PAO output: first BO ON to open - normal;
first BO ON to close - reverse
Polarity
****
Normal
For BO normally closed - normal;
BO normally open - reverse
Suppl Htg Make Lmt
****
55%
For BO object, output is active when input is above
this value.
Suppl Htg Differential
****
10%
For BO object, output changes from active to inactive
when input falls below make limit by this value.
Table 113: Sideloop PID Parameters
Parameter Name
Address
Default
Description
Setpoint
ADF 199
0
Current setpoint for the sideloop control algorithm
Offset
****
0
Deadband
****
0
Proportional Band
****
10
Integral Time
****
300 seconds
Self Tuning
****
-
Direct Acting
****
True
Period
****
60 seconds
Flag designating whether PRAC is used
Time period between PID calculations
124
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Table 114: Sideloop Output Parameters
Parameter Name
Address
Stroke Time
****
60 seconds
Stroke time for PAO output
Polarity
****
Normal
For PAO output
Polarity
****
-
BO normally closed - normal;
BO normally open - reverse
Sideloop Htg Make
Lmt
****
55%
For BO object, output is active when input is above
this value.
Sideloop Differential
****
10%
For BO object, output changes from active to inactive
when input falls below make limit by this value.
Default
Description
VMA Dual Duct Commissioning Parameters
An address entry of **** indicates that this parameter is not
Note:
mapped to an address.
Table 115: VAV Box Mode Parameters
Parameter Name
Address
Description
Present Value
ADI 67
Primary VMA control mode.
Command modes:
0 = Shutdown Closed
1= Shutdown Open
Auto modes:
2 = Satisfied
3 = Mixing
4 = Cooling
5 = Heating
6 = Suppl Htg
See the Key Concepts section for complete description.
Table 116: Occupancy Mode Parameters
Parameter Name
Address
Description
Schedule
ADI 78
0 - Unoccupied
1 - Standby
2 - Occupied
3 - No Schedule
This parameter provides a non-archivable point for scheduling
commands. If N2 communication fails, the Occupancy Mode Input
becomes the default mode. See the Key Concepts section for a
complete description.
Present Value
ADI 68
0 - Unoccupied
1 - Standby
2 - Occupied
See the Key Concepts section for complete description.
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note 125
Table 117: Command Modes Parameters
Parameter Name
Address
Description
Cold Deck Available
BD 75
Flag used to indicate whether the cold deck AHU is currently
operating
Hot Deck Available
BD 76
Flag used to indicate whether the hot deck AHU is currently operating
Warmup Req
BD 72
Flag used to request Warmup mode
Cooldown Req
BD 71
Flag used to request Cooldown mode
Low Limit Req
BD 73
Flag used to request Low Limit mode
Suppl Htg Available
BD 77
Used to specify when supplemental heating source is available
(for example, boiler and hot water pumps on)
Cold Deck Percent
ADF 71
Current cold deck flow setpoint as a percentage between the current
cold deck minimum and cooling maximum flow setpoints. This point
should be used in conjunction with the Hot Deck Percent parameter to
command multiple slave controllers that condition a space with a
single zone sensor and multiple VMA controllers. This parameter is
visible only in Test and Balance View.
Hot Deck Percent
ADF 72
Current hot deck flow setpoint as a percentage between the current
hot deck minimum and heating maximum flow setpoints. This point
should be used in conjunction with the Cold Deck Percent parameter
to command multiple slave controllers that condition a space with a
single zone sensor and multiple VMA controllers. This parameter is
visible only in Test and Balance View.
Table 118: Temperature Setpoints Parameters
Parameter Name
Address
Description
Actual Cooling Setpt
ADF 4
See the Temperature Setpoint Configuration for VMA Dual Duct
Applications topic in the Key Concepts section for complete details.
Actual Heating Setpt
ADF 5
See the Temperature Setpoint Configuration for VMA Dual Duct
Applications topic in the Key Concepts section for complete details.
Table 119: Temperature Biases Parameters
Parameter Name
Address
Description
Actual Cooling Bias
ADF 6
Actual Cooling Bias = specified cooling bias of current Occupancy
mode
Actual Heating Bias
ADF 7
Actual Heating Bias = specified heating bias of current Occupancy
mode
Table 120: Temperature Diagnostics Parameters
Parameter Name
Address
Description
MovAvg ZT Err
ADF 39
Moving average of the error between the current zone temperature
and the zone temperature setpoint
MovAvg ABS ZT Err
ADF 40
Moving average of the absolute value of the zone temperature error
Inadequate Cooling
BD 3
True when box is unable to maintain the zone at the cooling
temperature setpoint and is not starved for flow
Inadequate Heating
BD 4
True when all available heat is at maximum, but the box is unable to
maintain the zone at the heating setpoint
126
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Table 121: Summer Winter Comp. Parameters
Parameter Name
Address
Description
Outdoor Air Temp
ADF 81
Outdoor air temperature value provided via network
Summer
Compensation
ADF 8
See Summer and Winter Compensation in the Application Logic topic
in this document.
Winter Compensation
ADF 9
See Summer and Winter Compensation in the Application Logic topic
in this document.
Table 122: Cold Deck Status Parameters
Parameter Name
Address
Description
Present Value
****
Output of the P-Adaptive control algorithm. See the Key Concepts
section for more information.
Cold Deck Flow
ADF 36
Current flowrate being delivered by the cold deck
Setpoint
ADF 65
Current setpoint for the cold deck
Table 123: Hot Deck Status Parameters
Parameter Name
Address
Description
Present Value
****
Output of the P-Adaptive control algorithm. See the Key Concepts
section for more information.
Hot Deck Flow
ADF 37
Current flowrate being delivered by the hot deck
Setpoint
ADF 66
Current setpoint for the hot deck
Table 124: Total Flow Status Parameters
Parameter Name
Address
Description
Present Value
****
Output of the P-Adaptive control algorithm. See the Key Concepts
section for more information.
Total Flow
ADF 38
Current flowrate being delivered by the box (cold deck + hot deck)
Setpoint
ADF 67
Current setpoint for the box (cold deck + hot deck)
Table 125: Indoor Air Quality Parameters
Parameter Name
Address
Description
CD OA Percent
ADF 75
Percent outdoor air included in the cold deck supply. Value must be
mapped via a network variable.
HD OA Percent
ADF 76
Percent outdoor air included in the hot deck supply. Value must be
mapped via a network variable.
CD IAQ Min Flow
****
Minimum amount of cold deck air due to IAQ requirements
HD IAQ Min Flow
****
Minimum amount of hot deck air due to IAQ requirements
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note 127
Table 126: Flow Diagnostics Parameters
Parameter Name
Address
Description
MovAvg CD Err
ADF 41
Moving average of the error between the cold deck flow and setpoint
MovAvg ABS CD Err
ADF 42
Moving average of the absolute value of the cold deck flow error
MovAvg HD Err
ADF 43
Moving average of the error between the hot deck flow and setpoint
MovAvg ABS HD Err
ADF 44
Moving average of the absolute value of the hot deck flow error
MovAvg Total Err
ADF 45
Moving average of the error between the total flow and setpoint
MovAvg ABS Total Err
ADF 46
Moving average of the absolute value of the total flow error
Starved Cold Deck
BD 50
True if the box is unable to maintain the cold deck flow setpoint
(that is, damper remains saturated at 100% open)
Starved Hot Deck
BD 51
True if the box is unable to maintain the hot deck flow setpoint
(that is, damper remains saturated at 100% open)
Table 127: Cold Deck Actuator Parameters
Parameter Name
Address
Description
Reliability
ADI 18
Reliability of the value or the reason for not being trustworthy if
unreliable
Setup
****
Actuator type
Output
ADF 34
Estimated position (0-100%) of the damper actuator
Present Value
ADF 68
The current command to the actuator
Autocal
****
SMO calibration command
Table 128: Hot Deck Actuator Parameters
Parameter Name
Address
Description
Reliability
ADI 19
Reliability of the value or the reason for not being trustworthy if
unreliable
Setup
****
Actuator type
Output
ADF 35
Estimated position (0-100%) of the damper actuator
Present Value
ADF 69
The current command to the actuator
Table 129: Actuator Diagnostics Parameters
Parameter Name
Address
Description
MovAvg CD Reversals
ADF 47
Moving average of the cold deck hourly reversals over the past
24 hours
MovAvg CD Duty
Cycle
ADF 48
Moving average of the cold deck actuator duty cycle over the past
24 hours
MovAvg HD Reversals
ADF 49
Moving average of the hot deck hourly reversals over the past
24 hours
MovAvg HD Duty
Cycle
ADF 50
Moving average of the hot deck actuator duty cycle over the past
24 hours
128
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
Table 130: Autocalibration Parameters
Parameter Name
Address
Description
Autocal Time
****
Current number of hours since most previous autocalibration
Autocal Req
BD 70
Flag used to request an autocalibration
Autocal Active
BD 60
Status of the autocalibration routine
Table 131: Occupancy Timer Parameters
Parameter Name
Address
Description
Present Value
BD 12
Status of the occupancy timer
Time Remaining
****
Time remaining in the current temporary occupancy period (if active)
Table 132: Lighting Parameters
Parameter Name
Address
Description
Present Value
ADI 65
Status of lighting control
Table 133: Energy Balance PID Parameters
Parameter Name
Address
Description
Qdot Setpoint
ADF 51
Current heat transfer setpoint (BTU/hr). This value is calculated by
subtracting Qdot Offset from the PID Present Value.
Process Variable
****
Current zone temperature
Setpoint
****
Current zone temperature setpoint
Qdot Offset
****
Offset of PID Present Value to ensure High Limit is always > 0.0 (only
visible in Diagnostic view).
High Limit
ADF 22
Maximum value for PID Present Value
Present Value
ADF 70
Current output of the PID
Low Limit
ADF 21
Minimum value for the PID Present Value
Saturation Status
****
Low (High) if output of PID remains 0.0 (100.0) for saturation time
Table 134: Suppl Heating PID Parameters
Parameter Name
Address
Description
Present Value
ADF 73
Output of the PID control algorithm
Process Variable
****
Current zone temperature
Setpoint
****
Current zone temperature heating setpoint
Saturation Status
****
Low (High) if output of PID remains 0.0 (100.0) for saturation time
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note 129
Table 135: Suppl Heating Output Parameters
Parameter Name
Address
Description
Object Type
****
Standard output object type selected (for example, BO, PAO, AO,
DAO, EHS)
Present Value
ADI or
ADF 141
The current output command
Actual Stage
ADI 6
For an EHS object, the actual stages active (different from present
value due to min flow and stage timing)
Input
ADF 28
Input signal from Supplemental Heating PID output
Output
ADF 29
Estimated position of a PAO object
Interstage Off Delay
****
Delay between turning off subsequent EHS stages
Interstage On Delay
****
Delay between turning on subsequent EHS stages
Make Limit
****
Make limit (or limits) for EHS objects
Break Limit
****
Break limit (or limits) for EHS objects
Min Off Limit
****
Above this value, a DAO object remains on at 100%.
Min On Limit
****
Below this value, a DAO object remains off at 0%.
Table 136: Sideloop PID Parameters
Parameter Name
Address
Description
Present Value
****
Output of the PID control algorithm
Process Variable
****
Current value of the input sensor
Saturation Status
****
Low (High) if output of PID remains 0.0 (100.0) for saturation time
Table 137: Sideloop Output Parameters
Parameter Name
Address
Description
Object Type
****
Standard output object type selected (for example, BO, PAO, AO,
DAO, EHS)
Present Value
ADI or
ADF 142
The current output command
Actual Stage
ADI 31
For an EHS object, the actual stages active (different than present
value due to min flow and stage timing)
Input
ADF 32
Input signal from Sideloop PID output
Output
ADF 33
Estimated position of a PAO object
Interstage Off Delay
****
Delay between turning off subsequent EHS stages
Interstage On Delay
****
Delay between turning on subsequent EHS stages
Make Limit
****
Make limit (or limits) for EHS objects
Break Limit
****
Break limit (or limits) for EHS objects
Min Off Limit
****
Above this value, a DAO object remains on at 100%.
Min On Limit
****
Below this value, a DAO object remains off at 0%.
130
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note
VMA Dual Duct Mapped Input/Output Attributes
The general characteristics of each of the input and output options
available for use in VMA applications, as well as a detailed description
of each of the viewable attributes, are given in the Input/Output
Options topic in the Attributes and Parameters section of this
document. A list of the attributes that are mapped to the
Metasys Network for the inputs and outputs of the VMA application
are shown in Table 138.
Table 138: VMA Dual Duct Application Input and Output Attributes Mapped to the
Metasys Network
Attribute
Short Name
Long Name
Address
ZN-T
Present Value
AI n
ZTREL
Reliability
ADI 20
W-C-ADJ
Present Value
AI n
RAREL
Reliability
ADI 21
Zone Temperature (AI)
Remote Adjust (AI)
Remote Setpoint (AI)
REM-SET
Present Value
AI n
RSREL
Reliability
ADI 22
DA-T
Present Value
AI n
DATREL
Reliability
ADI 24
Discharge Air Temp (AI)
Cold Deck Delta P (AI)
CD-VP
Present Value
AI n
CDDPREL
Reliability
ADI 26
HD-VP
Present Value
AI n
HDDPREL
Reliability
ADI 27
Hot Deck Delta P (AI)
Total Flow Delta P (AI)
TOT-VP
Present Value
AI n
TOTDPREL
Reliability
ADI 28
SLAI
Present Value
AI n
SLIREL
Reliability
ADI 25
Sideloop Input (AI)
Occupancy Button (BI)
TEMP-OCC
Present Value
BI n
OCCCNREL
Reliability
ADI 10
OCC-S
Present Value
BI n
OCCSNREL
Reliability
ADI 9
Occupancy Sensor (BI)
Continued on next page . . .
Variable Air Volume Modular Assembly (VMA) 1400 Series Application Note 131
Attribute (Cont.)
Short Name
Long Name
Address
LT-ALM
Present Value
BI n
LLCNREL
Reliability
ADI 11
RADHTG
Present Value (PAO, DAO)
ADF 141
RADHTG
Present Value (AO)
AO n
RADHTG-C
Present Value (BO)
BO n
RADHTG
Present Value (EHS)
ADI 141
Low Limit Contact (BI)
Suppl Heating Cmd (PAO, AO, DAO, BO, EHS)
SHOUTPUT
Output (PAO, AO, DAO, EHS)
ADF 29
SHOUTPUT
Output (BO)
ADI 29
SHREL
Reliability
ADI 5
SHACTSTG
Actual Stage (EHS)
ADI 6
SHINPUT
Input (EHS)
ADF 28
SHINSOFF
Instant All Off (EHS)
BD 43
Present Value (SMO, PAO)
ADF 68
Cold Deck Damper Cmd (SMO, PAO, AO)
CDDPRPV
CD-DPR-C
Present Value (AO)
AO n
CDDPRPOS
Output
ADF 34
CDDPRREL
Reliability
ADI 18
Hot Deck Damper Cmd (PAO, AO)
HDDPRPV
Present Value (PAO)
ADF 69
HD-DPR-C
Present Value (AO)
AO n
HDDPRPOS
Output
ADF 35
HDDPRREL
Reliability
ADI 19
LTG-C
Present Value
ADI 65
LGHTREL
Reliability (SSO)
ADI 16
SLPAO, SLDAO
Present Value (PAO, DAO)
ADF 142
SLAO, SLBO
Present Value (AO, BO)
AO n, BO n
SLEHS
Present Value (EHS)
ADI 142
SLOUTPUT
Output (PAO, AO, DAO, EHS)
ADF 33
SLOUTPUT
Output (BO)
ADI 33
SLCREL
Reliability
ADI 30
SLACTSTG
Actual Stage (EHS)
ADI 31
SLINPUT
Input (EHS)
ADI 32
SLINSOFF
Instant All Off (EHS)
BD 45
Lights
Sideloop Cmd (PAO, AO, DAO, BO, EHS)
Controls Group
507 E. Michigan Street
P.O. Box 423
Milwaukee, WI 53201
www.johnsoncontrols.com
Published in U.S.A.
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