advertisement
Excel 15
W7760C Plant Controller
SYSTEM ENGINEERING
Table of Contents
® U.S. Registered Trademark
Copyright © 2000 Honeywell • All Rights Reserved
74- 3079
EXCEL 15 W7760C PLANT CONTROLLER
INTRODUCTION
Description of Devices
The Excel 15 W7760C Plant Controller is a device that can be used to monitor and control HVAC equipment and other miscellaneous loads using L protocol on an Echelon L
ON
ON
W
T
ALK
ORKS
communications
The W7760C Plant Controller communicates via the 78 kilo bits per second (kbps) L
ON
W
ORKS
network, using a Free
Topology Transceiver (FTT). The W7760C is compatible with the Excel 15 W7760A Building Manager, the S7760A
Command Display, individual Excel 10 Controllers and
T7300F/Q7300H Series 2000 Commercial Thermostats and
Communicating Subbases. The W7760C monitors and controls both local and remote controller points.
The W7760C also supports configurable control loops for a wide variety of applications.(Each of the following control strategies can be configured with a combination of features, up to the maximum number stated for each type of loop.)
— Scheduling (from a W7760A Building Manager).
— Demand Limit Control (from a W7760A Building Manager).
— Time-of-Day Bypass.
— Setpoint Reset.
— Adaptive Intelligent Recovery™.
— Sequencer.
— Lead/Lag.
— Analog Limit.
— Setpoint Override.
— Setpoint Alarming.
— Start/stop loops (eight maximum). Start/stop loops are used to turn equipment on and off based on a Time Of Day
(TOD) schedule or a Demand Limit Control (DLC) situation.
— General Purpose Configurable Proportional Integral
Derivative (PID) Control Loops (ten maximum). Modulating or staged output (up to four stages per sequencer). Built-in auxiliary output to coordinate pumps or fans.
— If/Then/Else Logic Loops (32 maximum).
— Math Functions: MIN, MAX, AVG, SUM, SUB, SQRT, MUL,
DIV, ENTHALPY (36 maximum).
The W7760C is used in conjunction with the following devices:
— Excel 15 W7760A Building Manager.
— Excel 15 S7760A Command Display.
— Excel 10 W7751B,D,F,H VAV II Controllers
— Excel 10 W7750A,B,C Constant Volume AHU Controller.
— Excel 10 W7753A Unit Ventilator Controller.
— Excel 10 W7761A Remote Input/Output (RIO) Device.
— T7300F/Q7300H Series 2000 Commercial Thermostat/
Communicating Subbase.
— Q7760A Serial L
ON
T
ALK
Adapter (SLTA).
— Q7740A,B FTT Repeater (2-way and 4-way).
— 209541B FTT Termination Module.
NOTEBOOK PC
BUILDING MANAGER
1 4 8 12 16
EXCEL 15
W7760A
PLANT
CONTROLLER
EXCEL 15
W7760C
EXCEL 10
UV
T7770 OR T7560A,B
WALL MODULE
MODEM
EIA-232
SERIAL
PORT
SLTA
17 23 30 31 37 44
S7760
L
ON
W
ORKS
BUS
T7300F/
Q7300H
EXCEL 10
RI0
Back Select
EXCEL 10
VAVII
Q7740A
2-WAY
REPEATER
EXCEL 10
VAVII
PLANT
CONTROLLER
EXCEL 15
W7760C
BUILDING MANAGER
1 4 8 12 16
EXCEL 15
W7760A
EXCEL 10 VAVII
EXCEL 10
UV
T7770 OR T7560A,B
WALL MODULE
1 2 3
MODEM
EIA-232
SERIAL
PORT
SLTA
17 23 30 31 37 44
S7760
L
ON
W
ORKS
BUS
T7300F/Q7300H
Back Select
Fig. 1. Typical system overview.
M14508
74-3079 2
The T7770 or T7560 direct-wired Wall Modules are used in conjunction with Excel 10 W7751, W7750 and W7753
Controllers.
EXCEL 15 W7760C PLANT CONTROLLER
Control Application
Fig. 2 shows a typical W7760C control application.
EXHAUST
AIR
EXHAUST AIR DAMPER
NC
NO
EXHAUST
FAN
OUTSIDE
AIR
NC
MIXED
AIR
TEMPERATURE
T
+
RETURN
FAN
-
HEATING
VALVE
COOLING
VALVE
FAN
ON
H
RETURN
AIR
HUMIDITY
T
RETURN
AIR
TEMPERATURE
RETURN
AIR
VARIABLE
SPEED
DRIVE
P T
FAN
SPEED
HUMIDITY
VALVE
DUCT
STATIC
DISCHARGE
AIR
TEMPERATURE
FAN
STATUS
1
1
DO
3 1
1&2
32
COM 2
DO
33
3
DO
34
3&4
35
COM 4
DO
36
5
DO
37
5&6
38
COM 6
DO
39
7
DO
40
7&8
41
COM 8
DO
42
20
43
VDC
GND
44
2
45
24VAC
46
COM
47
24VAC
48
LINE
E
49
GND 1
AO
50
GND
51
2
AO
52
3
AO
53
GND
54
4
AO
55
5
AO
56
GND
57
6
AO
58
TRIAC EQUIVALENT CIRCUITS
HONEYWELL
W7760C
PLANT
CONTROLLER
1
DO
3 1
COM
1&2
32
DI
1
1
2
GND
3
DI
2
4
DI
3
5
GND
6
DI
4
7
DI
5
8
GND
9
DI
6
10
DI
7
11
GND
12
DI
8
13 14
EBUS
1 2
2
DO
33
1 CONNECT EACH D0 COMMON TO EITHER TERMINALS
(45, 46) FOR LOW-SIDE SWITCHING OR
TERMINALS (47, 48) FOR HIGH-SIDE SWITCHING.
2 EACH REPRESENTS TWO CONDUCTORS.
15 16
EBUS
1 2
17
AI
1
18
GND
19
AI
2
20
AI
3
21
GND
22
AI
4
23
AI
5
24
GND
25
AI
6
26
AI
7
27
GND
28
AI
8
29
GND
30
GND
DUCT
STATIC
PRESSURE
NETWORK
OUTSIDE AIR
TEMPERATURE
T
ROOM
TEMPERATURE
M17292A
Fig. 2. Typical air handling unit control application.
Control Provided
The W7760C functions to monitor and control HVAC equipment and other miscellaneous loads using a L
ON
W
ORKS network.
Product Name
The Excel 15 W7760C Plant Controller is available in one model:
— The W7760C2009 Plant Controller.
3 74-3079
EXCEL 15 W7760C PLANT CONTROLLER
Organization of Manual
This manual is divided into four basic sections:
1. Introduction: Provides an overview of the W7760C, discusses any related devices, lists additional literature and furnishes a glossary of abbreviations and definitions.
2. Construction: Describes controller hardware.
3. Application Steps: A step-by-step procedure that provides the necessary information to plan and lay out the
W7760C application and accurately order materials
4. Appendices: Provide information that allows a configuration to start using Honeywells Excel L
ON
S
PEC
™ PC software.
The organization of the manual assumes a project is being engineered from start to finish. If an operator is adding to, or is changing an existing system, the Table of Contents can provide the relevant information.
Applicable Literature
The following list of documents contains information related to the Excel 15 W7760C Plant Controller and the EXCEL 5000
OPEN™ SYSTEM.
Form No.
Title
74-2976
74-2977
Excel L
ON
S
PEC
™ Specification Data
Excel L
ON
S
PEC
Software Release Bulletin
Excel L
ON
S
PEC
Help is internal to ZL7760A software
74-3069
74-3090
74-2865
74-3123
74-3080
95-7611
74-3079
74-2967
95-7565
Excel L
ON
S
TATION
™ Specification Data
Excel L
ON
S
TATION
Software Release Bulletin
Excel L
ON
S
TATION
Help is internal to ZL7761A software
L
ON
W
ORKS
Bus Wiring Guidelines
Light Commercial Building Solution System
Communication Guide
Excel 15 W7760C Plant Controller Specification
Data
Excel 15 W7760C Plant Controller Installation
Instructions and Checkout and Test
Excel 15 W7760C Plant Controller System
Engineering
Excel 15 W7760A Building Manager
Specification Data
Excel 15 W7760A Building Manager Installation
74-2969
74-2970
74-2972
95-7561
74-2974
74-2942
74-2953
95-7504
95-7553
Instructions and Checkout and Test
Excel 15 W7760A Building Manager System
Engineering
Excel 15 System Integration Manual
Excel 15 S7760A Command Display
Specification Data
Excel 15 S7760A Command Display Installation
Instruction
Excel 15 S7760A Command Display User Guide
Excel 10 W7751B,D,F VAV II Controllers
Specification Data
Excel 10 W7751H Smart VAV Actuator
Specification Data
Excel 10 W7751B,D,F VAV II Controllers
Installation Instructions and Checkout
Excel 10 W7751H Smart VAV Actuator
Installation Instructions and Checkout
74-2949
74-2956
95-7521
74-2958
74-2962
95-7520
74-2964
74-2698
95-7539
74-2699
63-1281
63-4366
74-2697
95-7538
74-3097
95-7620
74-2954
95-7511
74-3067
95-7613
74-2858
95-7555
95-7554
62-0155
62-0125
63-4365
Excel 10 W7751B,D,F,H VAV II Controllers
System Engineering
Excel 10 W7750A,B,C CVAHU Controller
Specification Data
Excel 10 W7750A,B,C CVAHU Controller
Installation Instructions and Checkout and Test
Excel 10 W7750A,B,C CVAHU Controller System
Engineering
Excel 10 W7753A Unit Ventilator Controller
Specification Data
Excel 10 W7753A Unit Ventilator Controller
Installation Instructions and Checkout and Test
Excel 10 W7753A Unit Ventilator Controller
System Engineering
Excel 10 W7761A RIO Device Specification Data
Excel 10 W7761A RIO Device Installation
Instructions and Checkout and Test
Excel 10 W7761A RIO Device System
Engineering
T7300F/Q7300H Series 2000 Commercial
Thermostats and Communicating Subbase
Specification Data
Q7300H Series 2000 Commercial Thermostat
Communicating Subbases Installation
Instructions
T7300F Series 2000 Commercial Microelectronic
Conventional or Heat Pump Thermostat
Installation Instructions
T7300F/Q7300H Series 2000 Commercial
Thermostats and Communicating Subbases
System Engineering
Q7300H Communicating Subbase System
Integration User Address Manual
Excel 10 T7770A,B,C,D,E,F,G Wall Module
Specification Data
Excel 10 T7770A,B,C,D,E,F,G Wall Module
Installation Instructions
T7560A,B Digital Wall Module Specification Data
T7560A,B Digital Wall Module Installation
Instructions
SLTA-10 Serial L
ON
T
ALK
Adapter Specification
Data
SLTA-10 Serial L
ON
T
ALK
Adapter Installation
Instructions
Q7752B PCMCIA L
ON
W
ORKS
PCC-10 Card
Specification Data
Q7752B PCMCIA L
ON
W
ORKS
PCC-10 Card
Installation Instructions
Excel 10 Q7740A,B FTT Repeaters Specification
Data
Excel 10 Q7740A,B FTT Repeaters Installation
Instructions
Excel 10 209541B Termination Module
Installation Instructions
Other Product Model Numbers
• Q7760A Serial Adapter.
• Q7740A,B FTT Repeaters.
• 209541B FTT Termination Module.
Refer to Table 22 in Application Step 5. Order Equipment for a complete listing of all available part numbers.
74-3079 4
EXCEL 15 W7760C PLANT CONTROLLER
Agency Listings
Device
W7760C Plant Controller
Agency
UL
Table 1. Agency Listings.
Comments
Tested and listed under UL916 (file number E14480). NEC Class 2 rated.
cUL Listed E14480. NEC Class 2 rated.
CE Level A general Immunity per European Consortium Standards EN50081-1 (CISPR 22,
Class B) and EN 50082-1:1992 (based on Residential, Commercial, and Light Industrial).
EN 61000-4-2: IEC 1000-4-2 (IEC 801-2) Electromagnetic Discharge.
EN 50140, EN 50204: IEC 1000-4-3 (IEC 801-3) Radiated Electromagnetic Field.
EN 61000-4-4:
EN 55022:
CISPR-22:
IEC 1000-4-4 (IEC 801-4)
Electrical Fast Transient (Burst). Radiated Emissions and
Conducted Emissions:
1987 Class B.
1985.
FCC Complies with requirements in FCC Part 15 rules for subpart J Class A Computing Device.
Operation in a residential area can cause interference to radio or TV reception and require the operator to take steps necessary to correct the interference.
Abbreviations and Definitions
AHU
Air Handling Unit; the central fan system that includes the blower, heating equipment, cooling equipment, ventilation air equipment, and other related equipment.
Application
A specific Building Control function.
Binding
The process of logically connecting network variables in one node to network variable(s) in other node(s). Binding is performed by a network management node that writes the binding information into the EEPROM of each Neuron each Neuron.
involved. The binding information is saved in the network image of
Building Manager
A L
ON
M
ARK
certified device that can be used to monitor and control HVAC equipment and other miscellaneous loads in a distributed network.
Bypass
Temporary override of the scheduled occupancy state to the occupied mode. At the end of the bypass time, the control returns to the scheduled occupancy state.
CO
Carbon Monoxide. Occasionally used as a measure of indoor air quality.
CO
2
Carbon Dioxide. Often used as a measure of indoor air quality.
Command Display
A device that is used to monitor and change parameter in a L
ON
W
ORKS
HVAC application.
Continuous Trend
A type of log that starts accumulating data after configuration and continues to record data until reconfigured. After a specific number of configured samples are recorded, the data is replaced on a first-infirst out basis. This results in the most recent data being in the trend at the time of viewing or downloading.
Control Loop
A control function; A type of function in a node that includes processes, loops and programs. A node can contain one or more control loops. (In Excel
10 devices, the control loop occupies the entire node.)
COS
Change of state; COS conditions are used with schedule states such as occupied and unoccupied.
Changing from the occupied mode to the unoccupied mode is COS.
CPU
Central Processing Unit; an EXCEL 5000
SYSTEM controller module.
OPEN
cUL
Underwriters Laboratories Canada.
CVAHU
Constant Volume AHU; Refers to a type of air handler with a single-speed fan that provides a constant amount of supply air to the space it serves.
CZS
Commercial Zoning System.
DDF
Delta Degrees Fahrenheit.
D/X
Direct Expansion; Refers to a type of mechanical cooling where the refrigerant is expanded to its cold state in a heat exchanging coil that mounts in the air stream supplied to the conditioned space.
DLC
Demand Limit Control; A function that controls the maximum power demand made on the whole system by shedding some of the demand when power usage exceeds the predefined limit. Shedding requires turning off some digital output, or changing a setpoint to a more economical level.
Echelon
The company that developed the L
ON
W
ORKS
Bus and the Neuron
L
ON
W
ORKS
Bus.
chips used to communicate on the
Economizer
Refers to the mixed-air dampers that regulate the quantity of outdoor air that enters the building. In cool outdoor conditions, fresh air can be used to supplement the mechanical cooling equipment.
Because this action saves energy, the dampers are often referred to as economizer dampers.
EEPROM
Electronically Erasable Programmable Read Only
Memory; The variable storage area for saving user setpoint values and factory calibration information.
5 74-3079
EXCEL 15 W7760C PLANT CONTROLLER
EMI
Electromagnetic Interference; Electrical noise that can cause problems with communications signals.
EMS
Energy Management System; Refers to the controllers and algorithms responsible for calculating optimum operational parameters for maximum energy savings in the building.
Enthalpy
The energy content of air measured in BTUs per pound (KiloJoules per Kilogram).
EPID Control
An Enhanced Proportional Integral Derivative control algorithm that improves the PID control algorithm by compensating for system dynamics and allows faster control response rate reset. It also incorporates a sequencer, AI limit, deadband, start ramp and setpoint override.
EPROM
Erasable Programmable Read Only Memory; The firmware that contains the control algorithms for the
Excel 15 and Excel 10 Controllers.
Excel 10s
A family of application specific HVAC Controllers such as the Excel 10 CVAHU, Excel 10 RIO and the
Excel 10 UV.
Firmware
Software stored in a nonvolatile memory medium such as an EPROM.
Floating Control
Refers to Series 60 Modulating Control of a valve or damper. Floating Control utilizes one digital output to drive the actuator open, and another digital output to drive it closed.
FTT
Free Topology Transceiver.
HVAC
Heating Ventilation and Air Conditioning.
IAQ
Indoor Air Quality. Refers to the quality of the air in the conditioned space, as it relates to occupant health and comfort.
I/O
Input/Output; the physical sensors and actuators connected to a controller.
I x R
I times R or current times resistance; refers to Ohms
Law: V = I x R.
K
Degrees Kelvin.
Level IV
Refers to a classification of digital communication wire. Formerly known as UL Level IV, but not equivalent to Category IV cable. If there is any question about wire compatibility, use Honeywell-approved cables (see Step
5 Order Equipment section).
L
ON
W
ORKS
Bus
Echelons L
ON
W
ORKS
network for communication among Excel 15 Controllers, Excel 10
Controllers and T7300F/Q7300H Commercial
Thermostat/Communicating Subbases.
L
ON
W
ORKS
Bus Segment
An L
ON
W
ORKS
Bus network that contains no more than 120 total (Excel 15 W7760A,Cs,
Excel10s and T7300F/Q7300H Commercial
Thermostat/Communicating Subbases). A segment can have a repeater that allows the bus wire length to be doubled.
Mandatory Mechanisms/Objects/Network Variables
Mandatory mechanisms, object and network variables that are implemented in all of the Excel 10 devices.
NamedObject
Objects that have names are called
NamedObjects. These objects are visible on the network as functional independent entities and are accessed by name. Typical examples of NamedObjects are controllers, control loops and logic function blocks.
NEC
National Electrical Code; The body of standards for safe field-wiring practices.
NEMA
National Electrical Manufacturers Association; The standards developed by an organization of companies for safe field wiring practices.
Network Management Node
A L
ON
W
ORKS
node that is responsible for configuring the network, installing the nodes, binding the network variables between nodes and general network diagnostics.
Network Time Master
A network time master will be the only device sending out the time/date. All other network devices will use the time/date from the network time master (even if they have their own real-time clock).
Network time master is chosen/configured from
LonSpec
and remains unchanged until reconfigured, even in the event of a failure on the network time master. (The Excel 15 W7760C can not be the network time master.)
Network Time Scheduler
The network time scheduler sends out current and next state (occupied, unoccupied or standby) and time until the next change of state
(TUNCOS) to all of its control loops based on the configured schedules.
Network Variables
A class of variables defined in Neuron C that allow communication over the L
ON
W
ORKS
network to other nodes on the network. For example; An output network variable in one node can be bound to the corresponding input network variable(s) in other node(s). Changing the value of the output network variable in one node causes the new value to be automatically communicated to the bound input network variable(s) in other node(s). When an input network variable is updated, an nv_update_occurs event is posted at the receiving node(s) so that the application program can take action based on the change. A network management node that explicitly reads and/or writes the network variable can also poll network variables. Network variables can contain one data field
(one or two bytes) or multiple data fields (a structure).
Node
A Communications Connection on a network; An
Excel 15 or Excel 10 Controller is one node on the
L
ON
W
ORKS
Bus network.
NV
Network Variable; An Excel 15 or Excel 10 parameter that can be viewed or modified over the L
ON
W
ORKS
Bus network.
PC
An Personal Computer with Pentium processor capable of running Microsoft
Windows 95.
74-3079 6
EXCEL 15 W7760C PLANT CONTROLLER
Plant Controller
A device that can be used to monitor and control HVAC equipment and other miscellaneous loads in a distributed network.
Proportional Control
A control algorithm or method in which the final control element moves to a position proportional to the deviation of the value of the controlled variable from the setpoint.
Proportional Integral (PI) Control
A control algorithm that combines the proportional control and the integral reset control algorithms. Integral reset virtually eliminates offset by gradually shifting the controlled output in the direction that brings the controlled variable back to the setpoint.
Proportional Integral Derivative (PID) Control
A control algorithm that enhances the PI control algorithm by adding a component that is proportional to the rate of change (derivative) of the deviation of the controlled variable. PID compensates for system dynamics and allows faster control response rate reset.
PWM
Pulse Width Modulated output; Allows analog modulating control of equipment using a digital output on the controller.
RCD
Remote Communication Device; For the Building
Management System, this is a piece of hardware that is functionally compatible to an SLTA and provides access directly to the L
ON
W
ORKS
Bus.
Recovery Mode or Recovery Period
The time in unoccupied periods when the temperature control is adjusting the control setpoint so that the space temperature reaches the occupied setpoint when the schedule change occurs.
Reset
The reset of a control loop varies depending upon the type of control loop being reset. A reset for a thermostat loop or a control loop changes the setpoint and the algorithm in the energy saving direction. A reset for a start/stop loop causes the digital output to go to the inactive state before returning to its normal scheduled state.
RIO
Excel 10 Remote I/O Device; Additional inputs and outputs that can be configured for use by an Excel 15
W7760A or W7760C.
RTC
Real-time clock.
RTD
Resistance Temperature Detector; Refers to a type of temperature sensor whose resistance output changes according to the temperature change of the sensing element.
Schedule
The structure that defines the occupancy states, setpoints and the time of the changes between these states.
SLTA
Serial L
ON
T
ALK
Adapter; A serial interface between the EIA-232 (serial port on a PC) and a L
ON
W
ORKS
Bus used to adapt transformer-coupled Echelon messages.
SNVT
Standard Network Variable Type.
TOD
Time-Of-Day; The scheduling of Occupied and
Unoccupied times of operation.
TUNCOS
Time Until Next Change Of State is a command that can be sent to other controllers.
UV
An Excel 10 Unitary heating/cooling Ventilation System
Controller.
VA
Volt Amperes; A measure of electrical power output or consumption as applies to an ac device.
Vac
Voltage alternating current; ac voltage rather than dc voltage.
VAV
Variable Air Volume; Refers to a type of air distribution system.
VOC
Volatile Organic Compound; Refers to a class of common pollutants sometimes found in buildings.
Sources include out-gassing of construction materials, production-line by-products, and general cleaning solvents. A VOC is occasionally used as a measure of indoor air quality.
W7750
The model number of the Excel 10 CVAHU
Controllers (also see CVAHU).
W7751
The model number of the Excel 10 VAV Box
Controllers (also see VAV).
W7753
The model number of the Excel 10 UV Controller
(also see UV).
W7760
The model number of the Excel 15 Building Manager
Controller and the Plant Controller (also see Building
Manager and Plant Controller).
W7761
The model number of the Excel 10 RIO Device.
Wall Module
The Excel 10 Space Temperature Sensor and other optional controller inputs are contained in the
T7770 or the T7560A,B Wall Modules. See Application
Step 5. Order Equipment for details on the various models of Wall Modules.
7 74-3079
EXCEL 15 W7760C PLANT CONTROLLER
CONSTRUCTION
Controller
The W7760C enclosure consists of a subbase and a snap-on
cover electronics assembly. See Fig. 3. The subbase has
terminal blocks (for inputs/outputs, communications and power wiring).
NOTE: If terminals 13 and 14 on the L
ON
W
ORKS
Bus are used as inputs and 15 and 16 are used as outputs and the snap-on cover/electronics assembly is removed from the subbase, then this causes the
L
ON
W
ORKS
Bus to have a break in it. To prevent the break from occurring, attach jumpers.
The cover/electronics assembly also includes a diagnostic
LED that is visible from the front. See Fig. 3.
The W7760C can mount in any orientation in a surface-mount or DIN rail installation. Ventilation openings enable heat dissipation regardless of the mounting orientation. Surfacemount installations use four screws to secure the subbase to the mounting surface. (Use screws appropriate for the
mounting surface.) For DIN rail installations. See Fig. 4.
Obtain DIN rail from local suppliers. DIN rail standard
EN 50 022, 1-3/8 x 5/16 in. (35 x 7.5 mm). Also for every
W7760C using DIN rail, purchase locally two each DIN rail adapters part number TKAD from Thomas and Betts.
The W7760C includes a L
ON
W
ORKS
Bus communications jack to allow a network compatible tool (such as the L
ON
S
PEC configuration tool) to access the L
ON
W
ORKS
A pushbutton switch is available to perform the service pin
operation used in the commissioning process. See Fig. 3.
L
ON
W
ORKS
NETWORK JACK COVER ASSEMBLY
STATUS LED
SUBBASE ASSEMBLY
SERVICE PIN
PUSH BUTTON
W7760C PLANT CONTROLLER
Fig. 3. W7760C enclosure.
M16450A
3
2
1
M16451
Fig. 4. Using DIN rail adapters for mounting W7760C.
Fig. 5 and 6 show the W7760C dimensions.
74-3079 8
6-13/16 (153)
EXCEL 15 W7760C PLANT CONTROLLER
7-5/8
(194)
2-5/16 (59)
1-3/32
(28)
5-1/4
(133)
M18061
Fig. 5. W7760C assembly mounting dimensions in in. (mm).
Performance Specifications
3-5/32 (80) 1-1/4
(26)
CPU:
DS80C310.
UP
Fig. 6. W7760C subbase mounting dimensions in in. (mm).
M18062A
Memory Capacity:
128K EPROM for Operating System, 32K of flash for application programs, 32K of SRAM for runtime log
(capacitor backed).
Input Power:
20 to 30 Vac, 50/60 Hz, 18 VA consumption (no load). Input power is from a 24 Vac transformer.
Sensor Power Supply:
The W7760C provides a 20 Vdc (65 mA maximum) regulated power supply for powering analog input and output devices.
Field Wiring:
Screw terminals accept 14 AWG (2.5 mm 2 ) wire or smaller.
Dimensions:
W7760C Cover Assembly: 7-1/2x5-1/4x1-15/16 in.
(191x133x49 mm).
W7760C Subbase: 7-3/4x5-3/4x15/16 in. (197x146x24 mm).
Environmental Limits:
Operating Temperature: -40 to 150°F (-40 to 65.5°C).
Shipping/Storage Temperature: -4 to 122°F (-20 to 50°C).
Relative Humidity: 5 percent to 95 percent non-condensing.
9 74-3079
EXCEL 15 W7760C PLANT CONTROLLER
Communications
The W7760C Controller uses Echelon L
ON
T
ALK
protocol and complies with for the Free Topology Transceiver (FTT) transformer-coupled communications port that runs at
78 kilobits per second (kbps). Using the transformer-coupled communications interface offers a much higher degree of common-mode noise rejection while ensuring dc isolation.
Cable Types
Approved cable types for L
ON
W
ORKS
Bus communications wiring is Level IV 22 AWG (0.34 mm 2 ) plenum or nonplenum rated unshielded, twisted pair, solid conductor wire. For nonplenum areas, use Level IV 22 AWG (0.34 mm 2 ) such as
U.S. part AK3781 (one pair) or U.S. part AK3782 (two pair). In plenum areas, use plenum-rated Level IV, 22 AWG (0.34 mm 2 ) such as U.S. part AK3791 (one pair) or U.S. part
AK3792 (two pair). See Tables 20 and 21 for part numbers.
Contact Echelon Corp. Technical Support for the recommended vendors of Echelon approved cables.
WIRING CONFIGURATION/DISTANCE
The FTT supports polarity insensitive free topology wiring.
This frees the system installer from wiring using a specific bus topology. T-tap, star, loop, and mixed wiring topologies are all supported by this architecture. The maximum L
ON
W
ORKS
Bus length when using a combination of T-tap, star, loop, and bus wiring (singly terminated) is 1640 ft. (500m) with the maximum node-to-node length of 1312 ft. (400m). In the event that the total wire length is exceeded, then a Q7740A 2-Way Repeater or a Q7740B 4-Way Repeater can be used to allow the number of devices to be spread out as well as increasing the length of wire over which they communicate.
When utilizing a doubly terminated L
ON
W
ORKS
Bus structure, use a continuous daisy-chain with no stubs or taps from the main backbone, The maximum L
ON
W
ORKS
Bus length is
4593 ft. (1400m) with the maximum node-to-node length of
3773 ft. (1150m).
FTT networks are very flexible and convenient to install and maintain, but it is imperative to carefully plan the network layout and create and maintain accurate documentation. This aids in compliance verification and future expansion of the
FTT network. This also keeps unknown or inaccurate wire run lengths, node-to-node (device-to-device) distances, node counts, total wire length, inaccurate repeater/router locations, and misplaced or missing terminations minimized. Refer to
L
ON
W
ORKS
Bus Wiring Guidelines form, 74-2865 for complete description of network topology rules.
OPERATION
General Information
The W7760C Plant Controller is a L
ON
M
ARK
™ compliant general purpose controller intended for use in a wide range of applications such as control air handling units, large air handling plants, heating plants, cooling plants, pumping systems, and other HVAC mechanical room applications. The controller combines the ease of configuring an application specific controller with the flexibility in application of a fully programmable controller by providing control algorithm building blocks that can be combined to meet most HVAC application requirements.
Detailed descriptions Start-Stop Loops, Control Loops, Logic
Loops, and Math Functions are provided later in this text.
In planning and configuring a W7760C, the following items should be considered.
Network Point Data Operation
Refer to Input and Output Summary, Remote Points and
Network points for more information on network points.
Network data points (network variables) are defined as being referred (also called bound points) or polled. The difference is in the network process used to communicate from one controller to another.
In general, most defined data points have two components, the network variable input (nvi) and the network variable output (nvo). The nvi is used to receive data from the network and the nvo is used to send data out to the network.
Referred points are best used when a point data such as an outside air is originated in one controller and is to be used in a number of other controllers on the network. Referred (or bound) points are configured such that the controller generating the nvo (the source controller) will transmit the point data whenever it changes or within a prescribed time period (55 seconds). Controllers that are to receive the data are configured with nvi’s that match the data type (i.e. outside air temperature). The controller then monitors the network for the point data from the source controller and writes the data to the nvi for use in the controller. If the nvi is not updated within a prescribed time period called the fail detect time
(300 seconds), an alarm message is generated and the input will be treated as a sensor fault.
NOTE: It is imperative that the default values of 55 seconds and 300 seconds are not changed. These values have been determined for optimum system performance. The failure detect time must be at least
5 times the update time.
Polled points are best used when a controller needs to read data from one or more controllers on the network. In polling, the controller requiring data from the network initiates a request (poll) for a specific point from a specific controller. The controller with the point data then responds returning the point data to the requesting controller. The W7760C polling algorithm polls each point every 2 seconds. If the response is not received within 10 seconds the poll is changed to one every 30 seconds. When the response is received the poll is returned to once every 2 seconds.
User Name Assignment
Each W7760C controller and object (start-stop loop, control loop, logic loop, and math function) can be assigned a user name. The user name is 18 alpha numeric characters including spaces.
The user name is the address (user address) for each point in the system. A given point in the system is identified by controller name and point name. Each name within a controller must be unique, but point and object names can be repeated in different controllers. This process makes it very easy to share data between controllers using Refer Points.
Operator interface devices display user names.
74-3079 10
EXCEL 15 W7760C PLANT CONTROLLER
A consistent naming convention will make the configuration process easier. It is good practice that the name identify the associated function. For example, analog inputs might include the suffix.AI and control loops the suffix.CL. The suffix makes searching for and selecting the correct input or output much simpler.
Operator interface devices often display point data in alphabetical order based on the user name. To control the specific order in which point data is displayed, consider a naming strategy that will order the points in the sequence desired for display.
LED Operation
The W7760C Plant Controller is equipped with an LED visible in the center of the front cover. The LED provides visual
indication of the controller operating status as seen in Table 2.
Table 2. Controller Operating Status.
Alarm Condition
No alarms 1
Service LED Blink Rate a
(cycles/second)
Any alarm condition Fast b
or steady OFF
Initialization Steady ON a b
The service LED blink rate is not affected by alarm reporting suppression.
Fast is any blink rate quicker than 1/2 second on and
1/2 second off.
Input/Output Summary
The W7760C Plant Controller algorithms can use inputs and
outputs of multiple types. See Table 3 for the input and output
types.
Table 3. W7760C Input And Output Types.
Type Description
Physical points Inputs and outputs that are physically connected to the controller (local points).
Remote points Point data from another controller on the network read or sent through the network.
Setpoints A table that has up to 40 analog values.
Pseudo points The outputs of start/stop loops, control loops, logic loops and math functions.
Network points Standard points with data generated from a controller and read across the network.
All inputs and outputs are either analog or digital. See Fig. 7.
Analog refers to a signal that changes to represent a variable value such as temperature, humidity or pressure. Digital refers to a signal with two states on or off. Digital points are also referred to as binary or discreet points.
IO-01
LonWorks Bus
Remote Points
Network Points
Analog Inputs
- Temperature
- Humidity
- Pressure
- Other
Digital Inputs
- Status
- Alarm
- Bypass
- Pulse Meter
- Other
Analog_Input_1
Analog_Input_2
Control, Logic, and Math Loops
Analog_Output_1
Analog_Output_2
Analog_Input_8
Digital_Input_1
Digital_Input_2
Digital_Input_8
Pseudo Points
Analog_Output_6
Setpoints
Setpoint _1
Digital_Output_1
Digital_Output_2
Setpoint_40
W7760C Plant Controller
Digital_Output_8
Analog Outputs
- Damper Actuators
- Valve Actuators
- Variable Freq. Drives
- Other
Digital Outputs
- Starters
- Relays
- Solenoid Valves
- Damper Actuators
- Valve Actuators
- Other
Fig. 7. W7760C Plant Controller inputs and outputs.
Physical Inputs and Outputs
The W7760C Plant Controller has physical connections for eight analog inputs, eight digital inputs, six analog outputs and eight digital outputs.
Analog Inputs
The W7760C has eight analog inputs (AI1 through AI8).
These analog inputs are used to monitor external conditions such as temperature, humidity or pressure and other variables. These AIs are used for monitoring and as inputs to control loops, logic loops and math functions. The W7760C samples each of the eight AIs at least once per second. Each analog input can be assigned a unique native language name
11 74-3079
EXCEL 15 W7760C PLANT CONTROLLER
(refer to General Information, User Name Assignment). The name is stored in the controller and is used by other devices including the operator interfaces to identify the input.
The AIs can be individually configured as:
Resistive:
— With an input range of 100 to 6500 ohms.
— With an Accuracy of
±
10 ohms.
— An AI less than 100 ohms detects as a short and an AI that is greater than 10,000 ohms detects as an open.
— Has a linear scale of input range that matches assigned engineering units.
Voltage:
— With an input range of 0 to 10 Vdc
NOTE: 4 to 20 mA signals use an external 500 ohm precision resistor.
— With an Accuracy of
±
±
3 percent of the input range or
10 millivolts, whichever is greater.
— An AI greater than 10 Vdc detects as an open.
— With a Sensor output impedance that is less than
2000 ohms.
— That has a linear scale that matches the input range.
20K NTC Resistive:
— That has a preconfigured RTD-the 20KOhm Negative
Temperature Coefficient.
— With a temperature to resistance range of -40 to 239°F
(-40 to 115°C) 839K ohms to approximately 695 ohms.
— That has open/short detection.
Digital:
— That senses dry contact closure.
— Functions as a digital input.
Engineering units can be customized for each AI.
Any configured analog input can be assigned as a network point. Network point types are OD Temp (outdoor temperature), OD Hum (outdoor humidity), and Discharge
Temp (discharge air temperature). Only one input can be assigned as any given network variable type.
Digital Inputs
The W7760C has eight digital inputs (DI1 through DI8). These digital inputs monitor status, alarm, bypass, pulse meters and other switched signals. DIs are used to monitor status, initiate alarms and as inputs to start/stop loops, control loops and logic loops for switching actions. The W7760C samples each of the eight DIs at least once a second.
Each DI can be assigned a unique native language name.
The name is stored in the controller and is used by other devices including the operator interfaces to identify the input.
A DI requires a dry contact (no external power) to switch
10 mA at 5 Vdc. It is imperative that input devices are rated for switching electronic signals.
DIs can be individually configured as:
— Normally Open or Normally Closed; The physical DI state is inactive (false) when the input contact is in the normal position.
— Maintained; The logical input state tracks the physical input state (contact). This requires the contact to change state for a period greater than 50 milliseconds.
— Momentary; The logical input state toggles (inactive/active) each time the physical input state switches to active. This requires the contact to change to the active state for a period greater than 50 milliseconds.
— Counter Slow; This counts the number of pulses (the physical input state is transitioned to active) up to 65,535 pulses. The next pulse resets the counter to zero.
Maximum Frequency: 0.4 Hz.
Minimum Pulse Width: 1.25 seconds.
Maximum Chatter: 50 milliseconds.
— Counter Fast; This counts the number of pulses (the physical input state is transitioned to active) up to 65,535 pulses. The next pulse resets the counter to zero.
Maximum Frequency: 15 Hz.
Minimum Pulse Width: 20 milliseconds.
Maximum Chatter: 5 milliseconds.
— Pulse Meter; These are used with power meters that have pulsed dry contact outputs. Pulses are multiplied by the scale factor (kWh/Pulse). If two DIs are configured as a
Pulse Meter, the values are added.
NOTES:
— Any two DIs can be configured as counters. The choices can be two counters that are slow or two counters that are fast or one slow and one fast counter.
— Two additional DIs can be configured for Pulse
Meters.
— Any two DIs can be configured as the sources for network sensor occupancy points (Sensor
Occupancy_[1,2] Out).
— Engineering units can be customized for each digital input. When selecting the engineering unit, the first unit in the pair is the inactive state and the second is the active state.
Analog Outputs
The W7760C has six analog outputs (AO1 through AO6).
These AOs are used to position valve and damper actuators, variable frequency drives, variable speed fans, step controllers and other devices that use a variable current or voltage output.
Each AO can be assigned a unique native language name.
The name is stored in the controller and is used by other devices including the operator interfaces to identify the output.
The AOs are 0 to 20 mA (configurable) current outputs that have a maximum load of 500 ohms with a 7 + bit resolution.
Adding an external 500 ohm precision resistor allows the AO to be configured to match signals that range between 0 to
10 Vdc.
The AO signal can be configured to reverse the signal action.
For example, the output could be configured so that an output of zero percent produces a 20 mA signal and an output of
100 percent produces 4 mA. This allows the output to match the controlled device without changing the operation of the control algorithm.
The AOs are also configurable as DOs, the output switches between the low and high configured output values. The digital load can not exceed 500 ohms.
74-3079 12
EXCEL 15 W7760C PLANT CONTROLLER
Digital Outputs
The W7760C has eight digital outputs (DO1 through DO8).
These DOs are used to turn equipment and devices on and off, to position valve and damper actuators and other controlled devices that use floating control or PWM input signals. These
DOs have 24 Vac Triacs that are isolated from controller power
(25 mA minimum to 100 mA maximum loads). Each pair of
Triacs shares a common terminal. See Fig. 8. Each DO is
sequenced on and off at 50
±
25 milliseconds. This prevents two or more Triacs from turning on or off at the same time.
requirements. The pulse width period is the time period for one pulse cycle and must be greater than or equal to the 100 percent pulse width value. The 0 percent pulse width is the time period of the pulse representing 0 percent output value from the controller (this must be greater than 0). One hundred percent pulse width is the time period of the pulse representing
100 percent output value from the controller. DOs that are connected to PWM devices are exempt from being sequencing on and off at 50 timing.
±
25 milliseconds in order to maintain their
DO X DO XY
COM
DO Y
M14541
Fig. 8. Digital output pair with common terminal.
Each DO can be assigned a unique native language name
(refer to General Information, User Name Assignment). The name is stored in the controller and is used by other devices including the operator interfaces to identify the output.
DOs can be configured to energize the physical output when the control output is on (de-energize when off) or to energize the physical output when the control output is off (de-energize when on). This enables the output to be configured to match the controlled device without changing the control algorithm.
For example: lights are in fail-safe on, so a control contactor with normally closed contacts is selected. This requires the output to be configured for Energized Off. An off command energizes the contactor that turns off the lights.
Any DO can be configured for floating control operation.
Floating control requires the configuration of two DOs, one to drive the controlled device open and one to drive it closed.
Good engineering dictates a pair of Triacs that shares a common terminal be used. The configured pair can be used by a control loop as a modulating output. Accurate control of floating devices requires that the device speed (the time required to drive from fully closed to fully open) be entered.
A maximum of two pair of DOs (four outputs) are configurable for floating operation.
The DOs are configurable as PWM outputs. See Fig. 9. The
DO configured as a PWM output can be used by a control loop as a modulating output. Configuring a DO as PWM requires that the PWM period, 0 percent pulse width and 100 percent pulse width be defined to match the controlled device input
0 PERCENT
PULSE WIDTH
PULSE WIDTH PERIOD
100 PERCENT
PULSE WIDTH
M14542
Fig. 9. Pulse width modulation signal.
Remote Inputs and Outputs
Remote points are used by control algorithms in the same manner as physical points.
REMOTE ANALOG INPUTS
The W7760C can use a maximum of 38* remote AOs. These consist of up to 18 AOs from W7761A Remote Input/Output devices (RIO) and 20* polled points. RIO AOs provide a maximum of six AIs from each of three RIO devices associated with the W7760C. RIO AIs are bound. See
General Information, Refer Points for additional information on bound points.
REMOTE DIGITAL INPUTS
The W7760C can use a maximum of 32* remote DIs. These consist of up to 12 DIs from W7761A RIO devices and 20*
polled points. RIO DIs provide a maximum of four DIs from
each of three RIO devices associated with the W7760C. RIO digital inputs are bound. See General Information, Refer
Points for additional information on bound points.
* The W7760C can use a maximum of 20 polled inputs. Each polled input is either analog or digital. The 20 polled inputs can be any combination of analog or digital points. A polled AI can be any analog point accessible to the network. The points can be physical AIs or outputs connected to another controller, setpoints or pseudo points providing they are available to the network. Analog point data available to the network varies by controller type. See General Information,
Polled Points for additional information on polled points.
13 74-3079
EXCEL 15 W7760C PLANT CONTROLLER
SETPOINTS
A W7760C Plant Controller can be configured with up to 40 setpoints for use as analog inputs to control loops, logic loops and math loops. Setpoints are analog constants that can be named and assigned engineering units. Setpoints are typically used as inputs to logic loops and math functions but can be used as an analog input to a control loop in some applications.
These setpoints can not be read or modified by an operator interface.
PSEUDO POINTS
Pseudo points are generated when a start/stop loop, control loop, logic loop or math function is configured. Pseudo points are analog or digital based on the output configuration. Start/ stop loops have one DO. The pseudo point name is
LoopName_Output. Control loops can be configured with as
many as 17 outputs. Pseudo points are created only for configured outputs and are either analog or digital matching
the configured output. See the pseudo point names in Table 4.
Analog Inputs
nviApplMode nviBldgStatPress nviDuctStatPress nviEmergOverride nviOccupancy nviRARH nviRATemp nviDATemp nviOdHum nviOdTemp
Table 4. W7760C Pseudo Point Names.
Configured as Analog
LoopName_ EPID
LoopName_ SEQ[n]
Configured as Staged
LoopName_ EPID_STAGE [n]
LoopName_ SEQ[n]_STAGE [n]
LoopName_ AUX
[n] is the sequence output number or stage output number. A logic loops pseudo analog point is created if the DCAO statement is configured and the digital point is created if logical OR is configured. The pseudo point names are
LoopName_ AO and LoopName_ DO respectively. Math
functions are exclusively analog with the point name
LoopName_ Output.
NETWORK POINTS
Network points are a special case of remote points. Network points are points with defined functions shared across the network. Refer to General Information, Refer Points for further information on network points. See network points used with
Table 5. W7760C Network Points.
Digital Inputs
nviEconEnable
Analog Outputs
nvoApplMode nvoOccupancy
Digital Outputs
nvoCoolUTML nvoEconEnable nvoHeatUTML
Analog and digital network inputs read their assigned values from the network if available. It is necessary to configure
Network Refer Points to assign the source controller/point to the destination controller/points. Analog and digital network outputs are assigned to the physical inputs when the inputs are configured. It is necessary to make the physical point assignment for the network output point to make the data available on the network. It is necessary to configure Network
Refer Points to assign the source controller/point to the destination controller/points.
BYPASS
DISABLE
DI
START - STOP LOOP
LoopName_Output
OCC OVERRIDE PRIORITY:
MIN ON TIME:
MIN OFF TIME:
BYPASS TIME:
DO
OUTPUT
DI
Configurations
Start/Stop Loops
There are eight Start/Stop loops that can be configured to turn equipment on and off based on the Time Of Day (TOD) scheduling and/or Demand Limit Control (DLC) load shed and restore operation. Minimum on and off times can be assigned.
Each start/stop loop is configured independently. See Fig. 10
for operation descriptions typical for all eight loops.
M14543
Fig. 10. Start/Stop loop schematic
TOD SCHEDULE
A W7760C Plant Controller start/stop loop receives the TOD status input from a W7760A Building Manager Controller TOD schedule. The TOD schedule is configured and assigned in the W7760A. See W7760A Building Manager System
Engineering form 74-2969 and the ZL7760A Excel
L
ON
S
PEC
™ software Help for information on configuring and assigning TOD schedules.
The TOD schedule sets the start/stop loop to one of two possible conditions occupied or unoccupied. A Standby event from the TOD schedule is treated as occupied. If a TOD schedule is not assigned or fails the default setting is occupied.
74-3079 14
EXCEL 15 W7760C PLANT CONTROLLER
BYPASS
When the start/stop loop is put into bypass operation during the unoccupied period, the output turns on for the configured bypass time. At the end of the time period the output turns off.
If bypass is initiated during the occupied period and the bypass timer has not timed out, the start/stop loop will remain on for the time remaining on the bypass timer. If the unoccupied period ends during the bypass period, the bypass operation terminates. The bypass time can be set from 0 to
1080 minutes in one minute increments.
Bypass operation can be initiated by the DI configured for bypass or from a network command. The Occupancy
Override Priority for the start/stop loop can be configured for
Network Wins or Last One Wins. If set for Network Wins and
the loop is placed in bypass by a network command, the DI is ignored until the bypass period has expired or is canceled by a network command. If set for Last One Wins the last command from either the network or the DI controls the bypass operation. The default Occupancy Override Priority for the start/stop loop configuration is Network Wins.
Once initiated by the bypass digital input, the bypass operation can not be terminated by the bypass input. If bypass is initiated during bypass operation, the bypass timer resets to the full bypass time.
MINIMUM ON AND MINIMUM OFF TIME
A minimum on time and a minimum off time can be configured individually for the output. The minimum times can be set from
0 to 254 minutes. The default value for each is 0. When the output is turned on, it remains on for the Minimum On Time setting and when it is turned off, it remains off for the Minimum
Off Time.
DEMAND LIMIT CONTROL
The start/stop loop can be assigned as a load in the Excel 15
W7760A Building Manager DLC program. See W7760A
Building Manager System Engineering form 74-2969 and the
ZL7760A Excel L
ON
S
PEC
™ software Help for information on configuring and assigning loads to a DLC program.
When there is no shed command from the DLC, all other functions operate as described above. When the start/stop loop receives a shed command from the DLC, it turns off the output regardless of the TOD schedule or the bypass status. It insures that the configured Minimum On Time requirement has expired before turning the output off. The output remains off until the DLC sends the loop a restore command. It remains off until the Minimum Off Time has been met. The output then returns to the control of the TOD schedule and bypass command in effect.
LOOP DISABLE
A DI can be selected to disable the start/stop loop. When disabled the loop TOD schedules, bypass or DLC and the output are off. The loop is enabled if the disable loop is not configured.
NOTE: The loop is enabled when the disable input is off
(false) and disabled when the input is on (true). Be sure the input logic meets the design requirements.
MANUAL MODE
The start/stop loop can be placed in the manual mode from a network command. In the manual mode the output can be commanded on or off regardless of the loop operation. When commanded to manual on or off, a network command is required to return the loop to automatic operation.
CONFIGURATION DATA
Start/Stop loops have the following configuration data:
— Loop Name: Should change to describe the function of the
Start/Stop loop. Default loop number.
— Bypass: (DI, optional) –
–
StartStop_Loop_# where # is the
Select from drop down list.
— Disable Loop: (DI, optional)
–
Select from drop down list.
— Start/Stop Output: (DO, required) list.
— Occupancy Override Priority
Network Wins or Last One Wins –
– Select from drop down
Select radio button.
— Minimum On Time: 0 to 254 minutes. Default is 0.
— Minimum Off Time: 0 to 254 minutes. Default is 0.
— Bypass Time: 0 to 1080 minutes. Default is 180.
Display Data:
— Enable/Disable/Manual mode.
— Effective Occupancy (occupied, unoccupied, standby or bypass.
— Scheduled Occupancy (occupied, unoccupied and standby.
— Occupancy Sensor state (on/off).
— System Mode (Auto/Off are the only system modes used.
(Off indicates the start/stop loop is disabled by the Disable
DI).
— DLC Shed status mode.
— Digital Output Status (on/off).
— Minutes remaining in Bypass state.
— Other status data from other sources in the Plant Controller such as: Loop Name.
Control Loops
The W7760C Plant Controller can be configured with up to ten control loops that are used to command outputs based on an input variable. A control loop is configurable to use either the
Enhanced Proportional + Integral + Derivative (EPID) algorithm or plus (+) the Honeywell proprietary nonlinear algorithm. Control loops have many built in features enabling them to command a wide variety of applications. Control loops can be cascaded with logic, math and control loops to create
complex control strategies. See Fig. 11.
15 74-3079
EXCEL 15 W7760C PLANT CONTROLLER
Main Sensor
Bypass Input
Reset Sensor AI
Recovery Sensor AI
AI
DI
Occupancy Sensor DI
Loop Disable Input DI
Limit Analog Input AI
Control Loop
Reset &
Recovery
Setpoints
Seq.
Control
Param.
Loop EPID Output
Seq1 (Heat) Output
Seq2 (Econ) Output
AO/DO
AO/DO
AO/DO
Setpoint Override 1 DI
Setpoint Override 4 DI
Setpoint
Override
Setpoint
Alarms
Seq3 (Cool) Output AO/DO
Auxiliary Output DO
— Scheduled setpoints: occupied, unoccupied and standby.
— Startup ramp time.
— Adaptive Intelligent Recovery™.
— Intelligent setback.
— Unoccupied bypass.
— Setpoint reset.
— Setpoint override.
— Demand Limit Control.
Fig. 11. Control loop schematic.
The fundamental operation of a control loop compares the value of the input sensor (measured variable) to the setpoint and calculates the output using the PID or nonlinear parameters. The complexity and flexibility of the W7760C control loop is due to the ability to modify the effective setpoint based on a number of the following control conditions:
E
p-1
E
E
T
i
T
d i d
= E
p
from the previous iteration.
= Integral Error.
= Derivative Error.
Sen = Input sensor value.
SP = Setpoint.
TR = Throttling Range.
= Integral Time.
= Derivative Time.
O = If (V x 100% + M) < 0%
Then 0%
Else if (V x 100% + M) > 100%
Then 100%
Else (V x 100% + M)
Additional flexibility is included in the control loop by configuring the outputs. Each control loop can configure the primary output as analog or staged (1 to 4 stages). The integrated sequencer outputs can scale the primary output into three additional outputs that can be configured as analog or staged (1 to 4 stages) outputs for use in sequenced applications (heating, economizer, and cooling). Each control loop has an auxiliary DO for controlling a fan or a pump.
Configured control loops run once per second.
PID CONTROL
The actual PID control algorithm is more complex, but can be explained as follows where:
O = Control signal output.
V = Calculated output.
M = Output Bias.
E
p
= Proportional Error.
Direct Acting or Reverse Acting
E = p
E =
∑ i
Sen - SP
TR
E p
T i
E = p
SP - Sen
TR
NOTE: The control loop signal output values are bound at
0 to 100 percent. However, the internal calculations are not bound and calculate positive and negative values to the limit of the floating point decimal range.
74-3079 16
EXCEL 15 W7760C PLANT CONTROLLER
PROPORTIONAL CONTROL
Proportional control is the function that determines the output
setting required to meet the load conditions. See Fig. 12 and 133.
120
110
100
0
-10
-20
80
60
40
20
THROTTLING
RANGE
CALCULATED OUTPUT
CONTROLLER OUTPUT
70 71 72 73 74 75
SENSOR INPUT VALUE
°
F
76 77 78
M1807
Fig. 12. Proportional direct acting (cooling).
The throttling range must be narrow enough to provide good control without becoming unstable. The throttling range is determined by a number of factors such as the control application, the response time to the equipment being controlled and the control algorithm in use. The narrower
(smaller) the throttling range, the more precise the control operation. The wider (larger) the throttling range, the more stable the control action. The objective is to set the throttling range to achieve the optimum balance between precision and stability.
INTEGRAL CONTROL
The purpose of the integral function is to eliminate the offset inherent in proportional control. Integral control functions to
hold the input sensor value at setpoint. See Fig. 14.
120
110
100
80
60
40
20
0
-10
-20
-30
70 71
THROTTLING
RANGE
CALCULATED OUTPUT
CONTROLLER OUTPUT
72 73 74 75 76
SENSOR INPUT VALUE
°
F
77 78
M18406
Fig. 13. Proportional reverse acting (heating).
In a direct acting control loop the output increases as the input sensor value rises above the setpoint. In a reverse acting control loop the output increases as the input falls below the setpoint. Direct and reverse acting are selected based on application requirements associated with the consideration that the setpoint is the no load value of a measured variable because it has 0 percent output when the energy input is closed or off. The physical outputs are configured to match the controlled devices (for example, normally open, normally closed, energized on, energized off). See the following application examples.
Direct Acting
Cooling
Dehumidification
Mixed Air
Static Pressure
Chilled Water Pump
Condenser Water Pump
Reverse Acting
Heating
Humidification
Hot Water Pump
Lighting
The proportional calculation determines the proportional error
(E
p
). E
p
is the deviation from the setpoint of the sensed medium (input sensor) divided by the throttling range in the units of the input sensor. The setpoint is the value of the input sensor that satisfies the control loop. When the input sensor value is at the setpoint, there is no proportional error and the output is 0 percent. The throttling range is the amount of change in the sensed medium that is required to drive the output from 0 to 100 percent. In proportional control the input value must deviate from the setpoint to initiate a change in the output.
17
65
INPUT
SENSOR
(
°
F)
60
55
THROTTLING
RANGE
SETPOINT
OUTPUT
(%)
100
75
50
25
0
E i
V = E i
+ E p
E p t
0 t
1 t
2 t
3 t
4 t
5
TIME INTERVAL t
6 t
7 t
8
M18405
Fig. 14. Proportional Integral control.
The integral function is a result of proportional error and time.
When the proportional error is greater than 0, the integral error is calculated and added to the proportional error to determine the control loop output. The integral error is cumulative and continues to increase as long as the proportional error is greater than 0. The increase in the output signal drives the controlled device further open and the controlled medium is brought closer to the setpoint. While the proportional error is reduced, the integral error continues to increase until the proportional error is eliminated. When the proportional error equals 0, the calculated integral error is no longer increasing or decreasing and no change is made to the output. When the proportional error is less than 0, the integral error decreases in value.
The integral time value is set in seconds based on the lag time of the controlled process. A slow process such as space temperature control requires a long integral time (600 seconds or more), while a fast process such as static pressure control requires a short integral time. An integral time of 0 (default) eliminates the integral function for the control loop.
Stability of the PI control loop is a balance of the throttling range and the integral time. If a PI control loop is unstable, increase the throttling range and/or increase the integral time.
Generally the throttling range required for PI control is greater than what is used for proportional control only. PI control should only be used in closed loop applications. Without feedback from the controlled medium, integral windup occurs.
Integral windup is a run away condition in which the integral
74-3079
EXCEL 15 W7760C PLANT CONTROLLER
error continues to increase due to the lack of proportional corrections. Plan the control strategy to insure integral windup does not occur or cause problems in the system performance.
NOTE: The output value read by all operator interface devices is the controller output value (0 to 100 percent) not the calculated output value. The user can not read the various components of a PI output to determine the respective contribution to the output value.
DERIVATIVE CONTROL
The purpose of derivative control is to reduce ringing or severe overshoot and undershoot when there is a significant
load change in a short period of time. See Fig. 15 through 17.
SETPOINT
Fig. 15. Proportional control.
SETPOINT
SETPOINT
T1
CONTROL
POINT OFFSET
T1 T2 T3 T4 T5 T6
TIME
C2099
CONTROL
POINT
OFFSET
T2 T3 T4 T5 T6
TIME
C2100
Fig. 16. Proportional integral control.
OFFSET
T1 T2 T3 T4 T5 T6
TIME
C2501
Fig. 17. Proportional integral derivative control.
NOTE: Few applications in HVAC require the use of derivative control. This is especially true with the W7760C
EPID control loop. EPID features such as start ramp eliminate many of the traditional control issues requiring derivative control. The loop stability and time associated with tuning derivative loops dictates that derivative not be used unless absolutely necessary.
Applications that are candidates for derivative control are very fast responding and subject to sudden large changes in external load conditions. These include static pressure control of fan systems, direct fired gas units, oversized controlled equipment and in some chilled water temperature control cases. Each application should be carefully examined before applying derivative control.
The derivative control function opposes change. The greater the proportional error the greater the braking effect of derivative control. The derivative function is calculated by subtracting the current proportional error value from the proportional error value of the previous loop execution and multiplying the result by the derivative time in seconds. The derivative error is summed with the proportional and integral errors to determine the loop output value.
In selecting the derivative time setting, the smaller the time setting, the smaller the derivative effect and the greater the time setting, the greater the derivative effect. A derivative time of 0 (default) eliminates the derivative error. If using the derivative time, it must be set to match the system response time of the controlled equipment and significantly impacts the throttling range and integral time settings. There are no application specific settings for the derivative time as the settings are unique to the equipment and load conditions.
DEADBAND OPERATION
Deadband control enhances the performance of conventional
PID controllers. It improves the controller stability and further extends actuator life. Deadband is expressed as a percentage of the throttling range. The range is (0 to 100) percent with a resolution of (1) percent. Deadband requirements are related to problems with actuator resolution and hysteresis. If the actuator resolution or hysteresis is unsuitable (too large), frequent control output oscillation results. Output oscillation is undesirable because it results in excess energy consumption and accelerated deterioration of the mechanical system
(actuators, valves and dampers).
Deadband control detects when the control loop is operating in an acceptable deadband region. For example, the absolute value of error less than the deadband threshold, and waits for somewhat steady state conditions. After these two conditions are confirmed, the control loop is opened, then the proportional error is set to zero and the controller output is held constant at the value of the previous time step. Deadband control is recommended when the primary control objective is to minimize actuator movement, tolerating small error offsets. If the error drifts out of the acceptable deadband region, the control loop closes and conventional control resumes.
Deadband control continues to search for acceptable deadband error and somewhat steady state conditions.
Deadband applies to PID control loops. It is ignored on nonlinear loops. To detect when the control loop operates in an acceptable deadband region, it is necessary to establish a delay time (time period in seconds). The delay time is the time that the proportional error must be less than the deadband
before the loop will hold a constant output value. See Table 6.
74-3079 18
EXCEL 15 W7760C PLANT CONTROLLER
Parameter
Deadband
Electric actuator
Pneumatic actuator with positioner
Pneumatic actuator without positioner
Variable speed fan motor drive
Deadband Delay
Table 6. Initial Settings For Single Loop Applications Using Modulating Motors.
HVAC Application
Heating Coil Cooling Coil Mixed Air Cold Climate Mixed Air Warm Climate Static Pressure
1.5°F
1.5°F
1.5°F
NA
1.0°F
1.0°F
1.0°F
NA
1.0°F
1.5°F
4.0°F
NA
300 seconds 300 seconds 300 seconds
0.75°F
1.0°F
3.0°F
NA
300 seconds
0.2 in. WC
0.2 in. WC
NA
0.1 in. WC
60 seconds
NONLINEAR CONTROL
The nonlinear algorithm is offered as an alternative to the PID algorithm. The nonlinear characteristics provide an output that is more stable than PID in some cases. PID is the primary choice, but if there is a problem achieving a stable loop, then the nonlinear algorithm could be the solution.
The W7760C has a control loop execution speed of once every second and is considered fast acting for HVAC applications. Standard PID control loops can be used in most
HVAC applications. The nonlinear algorithm is more successful for loops with output instability or where overshoot is not desirable. The nonlinear algorithm develops an error signal and makes relative corrections to reach and maintain zero offset. The main advantage of the nonlinear algorithm compared to the PID algorithm is that the nonlinear algorithm can not make large changes in the output. One parameter for the nonlinear algorithm is Max. Drive Percent. This value limits the amount that the output can change in one control interval. If there is a large change in the control point that causes a large offset, PID control makes a large change in the output (for example 50 percent). If the valve or damper is being controlled by a 90 second motor, by the next cycle it may have only moved a few percent causing the PID control to make another large change. This means that the output could be commanded to 100 percent, but the actual motor may only be at about 10 percent. This tends to cause the PID control to overshoot and become unstable. With the nonlinear algorithm limited to Max. Drive Percent per cycle, the commanded output follows closer to the actual motor position.
This results in a more stable control and very little overshoot.
The nonlinear algorithm can work better than PID for systems that have a very slow response or long sensor time constants.
For this algorithm the parameters are used to set a predefined control surface profile. The three parameters used to describe the control surface are:
1. Max. Drive Band – The absolute error (in delta units of the setpoint and sensor) at which the output changes by the amount equal to the Max. Drive Percent.
2. Max. Drive Percent – The maximum motor travel percentage per controller cycle (1 second). The amount the output changes in percent when the absolute value of the loop error is equal to the Max. Drive Band. The range is 0 to 100 percent with one tenth percent resolution.
3. Deadband – The error at which the algorithm does not take any action (the output remains unchanged). This is a percentage of the Max. Drive Band. The range is 0 to
100 percent with one tenth percent resolution
Guidelines for choosing these parameters follow:
1. The Max. Drive Band is selected close to the PID throttling range. However, it should be at least five times the deadband.
2. Max. Drive Percent should not be greater than the amount that the actual controlled actuator can change in one control interval.
Example:
In the W7760C a nonlinear algorithm is controlling an analog output that is driving a 90 second motor
(takes 90 seconds to travel one full stroke of its output range), the amount the actuator can change in one second (execution cycle for a control loop) is
1/90 = 1.1 percent. 1.1 percent is a good starting value for the Max. Drive Percent in this application.
This value should be made smaller if the process delays or long sensor time constants make the control overshoot excessively or become unstable.
3. Deadband – the deadband is chosen based on the resolution of the inputs and outputs plus the stability of the input sensor signal.
Example:
To control a valve with an actuator that has only
50 possible effective positions on a heating coil with a 50°F coil pickup, the output can only control to a
1°F resolution (50°F/50 positions). The output is not capable of resolving the output finer than 1°F. The minimum deadband for this application should be
0.5°F. The deadband can be widened to further minimize control actions if desired and also to eliminate problems with noisy sensor inputs. It is necessary to set the deadband to command the control to stop since the output is as close as it can be positioned or as close as needed. If the deadband is set at 0 or too narrow, the control loop continuously cycles the output back and forth by trying to get the error to zero which it can not do.
Output Bias
In some applications it may be desirable to have control above and below the setpoint. By changing the output bias to
50 percent it is possible to achieve an effective equivalent of a center setpoint. 50 percent output bias operates the same for direct and reverse acting control loops. No other change is made to the control loop operation. Direct acting and reverse
acting setpoint relationships are still enforced. See Fig. 18 for
output bias information.
19 74-3079
EXCEL 15 W7760C PLANT CONTROLLER
The PID algorithm calculates the control loop PID output above and below the setpoint to values limited only by the floating point decimal capacity of the controller. The final output is limited to a positive percentage (0 to 100) that represents the output change for the full throttling range with
0 percent or less PID error equaling 0 percent final output.
This also means that 100 percent or more PID error equals
100 percent final output. In a proportional only loop, the final output with 0 percent bias is 0 percent when the input equals setpoint (0 proportional error). Adding 50 percent bias to the
PID output results in an output of 50 percent when the total calculated PID error is 0 percent. The PID loop calculates a negative 50 percent to change the final output to 0 percent.
Also when the PID error is 50 percent the final output is
100 percent. The default parameter setting is 0 percent bias.
This means no bias is being added to the PID output calculation to set the output value. Selecting 50 percent bias adds 50 percent to the calculated output.
125
100
75
50
100
0% Bias
Output %
100
50% Bias
Output %
25
0
0
-25
-50
PID
Output %
0
-75
CL-19
Fig. 18. Output bias percentages.
Setpoint Control
EFFECTIVE SETPOINT
When working with control loops there is a distinction between the program setpoints and the effective setpoint. The program setpoints are the values entered into the controller program for the occupied, standby and unoccupied setpoints for each control loop that is configured. These values can be changed at any time from an operator interface. These setpoints are the initial values used in calculating the effective setpoint. The effective setpoint is the actual setpoint value used in a control loop to perform the PID and nonlinear calculations. It is the result of programmed and calculated setpoint values that are controlled by time and events. All setpoint values are in units of the main input sensor. Control loop occupied, standby and unoccupied setpoint values are required even if no schedule is assigned to a control loop. If a Setpoint Override digital input is active, the effective setpoint value is equal to the override setpoint value regardless of any other setpoints settings or calculations. If no Setpoint Override digital input is active, the effective setpoint value is equal to the setpoint determined by the current occupancy mode, setpoint reset,
DLC, occupancy sensor and unoccupied bypass.
The following relationship rules apply to setpoint values:
Direct Acting – Occupied must be
≤
Standby
≤
Unoccupied.
Reverse Acting – Occupied must be
≥
Standby
≥
Unoccupied.
The following relationship rules are rules are enforced in the
W7760C controller:
Direct Acting – The effective setpoint must be
≤
the unoccupied setpoint.
IF Occupied > Unoccupied THEN the effective setpoint equals unoccupied.
IF Standby > Unoccupied THEN the effective setpoint equals unoccupied.
Reverse Acting – The effective setpoint must be
≥
the unoccupied setpoint.
IF Occupied < Unoccupied THEN the effective setpoint equals unoccupied.
IF Standby < Unoccupied THEN the effective setpoint equals unoccupied.
Occupied setpoint reset can not be reset beyond the value of the unoccupied setpoint. This means the unoccupied setpoint must be set to accommodate the reset amount if it is used.
(See Setpoint Reset for more information.)
NOTE: L
ON
S
PEC
does not check or enforce the setpoint relationship rules.
Effective setpoints are determined by the effective occupancy state, setpoint reset, DLC setpoint bump, Adaptive Intelligent
Recovery, Intelligent Setback and setpoint override. See the
Table 7. Occupancy States.
Occupancy State
OCCUPIED
STANDBY
UNOCCUPIED
BYPASS
Meaning
The space is considered occupied and the control loop uses the occupied effective setpoint.
The space is considered to be in standby, a state between occupied and unoccupied, with the control loop using the standby effective setpoint.
The space is considered unoccupied and uses unoccupied setpoint.
The space is considered occupied but is not scheduled to be occupied and the control loop uses the occupied effective setpoint.
Refer to Fig. 19 for more information on how the effective
setpoint is determined. Refer to Fig. 20 for more information
on how the effective occupancy state is determined.
74-3079 20
EXCEL 15 W7760C PLANT CONTROLLER
OCCUPIED STATE OPERATION
Occupied is the default effective occupancy state for a control loop. A control loop is initialized in the occupied mode and remains in the occupied mode unless a network command changes the mode to standby or unoccupied.
Effective Setpoint Calculation
Where:
SP = Occupied Setpoint.
Rst = Max Reset Amount.
Reset = Reset Calculation.
DLC = DLC Setpoint Bump.
Effective setpoint is equal to:
(For Direct Acting)
IF Rst is positive
THEN
IF (SP + Reset) > (SP + DLC)
THEN (SP + Reset)
ELSE SP + DLC
ELSE (SP + Reset + DLC)*
(For Reverse Acting)
IF Rst is positive
THEN
IF (SP - Reset) < (SP - DLC)
THEN (SP - Reset)
ELSE SP - DLC
ELSE (SP - Reset - DLC)*
* Reset is a negative value.
When a direct acting control loop is in the effective occupied state and the Reset Amount is 0 or a positive value, the effective setpoint is a value greater than the occupied setpoint plus the calculated reset or the occupied setpoint plus the
DLC bump value. If reset and/or DLC is not configured, the respective values are 0. If reset is configured with a negative reset amount, the effective setpoint is the occupied setpoint minus the calculated reset plus the DLC bump value.
When a reverse acting control loop is in the effective occupied state and the Reset Amount is 0 or a positive value, the effective setpoint is a value less than the occupied setpoint minus the calculated reset or the occupied setpoint minus the
DLC bump value. If reset and/or DLC is not configured, the respective values are 0. If reset is configured with a negative reset amount, the effective setpoint is the occupied setpoint plus the calculated reset minus the DLC bump value.
If the control loop is configured with an occupancy sensor and the scheduled occupancy is occupied, the occupancy sensor switches the effective occupancy state between occupied when the sensor is active and standby when the sensor is inactive. See Bypass Operation for more information.
STANDBY STATE OPERATION
When a control loop is in the standby state, the effective setpoint is the standby setpoint plus the value calculated by the Adaptive Intelligent Recovery algorithm. The default settings for Adaptive Intelligent Recovery are 0. See Adaptive
Intelligent Recovery for more information. Setpoint Reset,
DLC setpoint bump and occupancy sensor functions do not operate in the scheduled standby mode.
UNOCCUPIED STATE OPERATION
When a control loop is in the unoccupied state, the effective setpoint is the unoccupied setpoint plus the value calculated by the Adaptive Intelligent Recovery algorithm. The default setting for the Adaptive Intelligent Recovery algorithm is 0.
See Adaptive Intelligent Recovery for more information. A control loop can be configured for no control action during the unoccupied state. In this case, PID or nonlinear calculation outputs are set to the startup value, usually 0 percent (off) during the unoccupied period.
BYPASS OPERATION
Bypass operation can be initiated in three ways:
1. A bypass command from an operator interface (use
L
ON
S
TATION
or a command display device). The control loop bypass timer is started and the bypass remains active until the timer times out or the bypass is terminated by a command.
2. The bypass operation of another loop or controller on the network is shared with the control loop. The control loop bypass timer is not used and the loop will remain in bypass for as long as the associated controller(s) remain in bypass.
3. A bypass input is configured for the control loop. A digital input that can be either a local physical point or a remote point from another controller on the network.
The control loop bypass timer starts and the bypass remains active until the timer times out.
See Table 8 for the scheduled state and bypass result.
Table 8. Scheduled State And Bypass Result.
Scheduled State
Occupied b
Effective Occupied
Occupied c
Effective Standby
Standby
Unoccupied
Bypass Result a
The effective occupancy state remains occupied (no change).
The effective occupancy state is occupied (changes from standby).
The effective occupancy state is occupied.
The effective occupancy state is bypass.
a
If the control loop bypass timer is active at the end of the scheduled occupancy the bypass operation for the new scheduled state is active for the bypass time remaining.
b
No occupancy sensor configured or occupancy sensor active.
c
Occupancy sensor configured and not active.
See Fig. 19 for a flow chart that explains how the effective
setpoint is determined.
21 74-3079
EXCEL 15 W7760C PLANT CONTROLLER
THIS FLOW CHART IS A SIMPLIFIED VIEW OF THE
PROCESS FOR THE PURPOSE OF ILLUSTRATION
* DEFAULT STATE START
SETPOINT
OVERRIDE
(1-4)
INACTIVE *
ACTIVE
EFFECTIVE
OCCUPANCY
(FIG. 20)
OCCUPIED *
STANDBY
UNOCCUPIED
BYPASS
IS
Override_SP
ACTIVE
?
N
IS
Eff_Occ =
Occupied
?
Y
Y
N
Y
N
IS
Rst_Amount
POSITIVE
?
Y
SET
Eff_SP =
Override_SP (1-4)
IS
Eff_Occ =
Bypass
?
Y
N
IS
Eff_Occ =
Standby
?
Y
SET
Eff_SP=Stby_SP
±
Recovery
N
IS
| Rst | >DLC
?
N
SET
Eff_SP=
UnOcc_SP
±
Recovery
SET
Eff_SP =
Occ_SP
±
Rst
±
DLC
±
Setback
Y
SET
Eff_SP =
Occ_SP
±
Rst
±
Setback
SET
Eff_SP =
Occ_SP
±
DLC
±
Setback
EFFECTIVE
SETPOINT
LEGEND
DLC - DEMAND LIMIT CONTROL = 0 IF NOT SHED, BUMP VALUE IF SHED
Eff_Occ - EFFECTIVE OCCUPANCY
Eff_SP - EFFECTIVE SETPOINT
Override_SP - OVERRIDE SETPOINT
Recovery - CALCULATED RECOVERY
Rst - CALCULATED RESET
Rst_Amount - MAX RESET AMOUNT POSITIVE OR NEGATIVE VALUE
Setback - CALCULATED SETBACK
Stby_SP - STANDBY SETPOINT
UnOcc_SP - UNOCCUPIED SETPOINT
±
- DIRECT ACTING USE +, REVERSE ACTING USE -
M18408
Fig. 19. Effective setpoint flow chart.
74-3079 22
EXCEL 15 W7760C PLANT CONTROLLER
See Fig. 20 for a flow chart that explains how effective
occupancy is determined.
START
* DEFAULT STATE
MANUAL
OVERRIDE
FIG. 26
OCCUPIED
STANDBY
UNOCCUPIED
BYPASS
OFF (NULL) *
THIS FLOW CHART IS A SIMPLIFIED VIEW OF THE
PROCESS FOR THE PURPOSE OF ILLUSTRATION
TOD
SCHEDULE
OCCUPIED *
STANDBY
UNOCCUPIED
OCCUPANCY
SENSOR
OCCUPIED *
UNOCCUPIED
IS
TOD =
Unoccupied
?
N
Y
Is
TOD =
Standby
?
Y
N SCHEDULED
OCCUPIED
Is
Occ Sensor
= Occ
?
Y
N
Y
IS
Man Override
= Off
?
N
SET Effective
Occupancy =
Unoccupied
SET Effective
Occupancy =
Standby
IS
Man Override
= Bypass
?
N
Y
IS
Man Override
= Unocc
?
N
Y
Y
IS
Man Override
= Standby
?
N
Man Override =
Occupied
IS
TOD =
Unoccupied
?
N
Y
SET Effective
Occupancy =
Occupied
SET Effective
Occupancy =
Bypass
Effective
Occupancy
(FIG. 19)
M18409
SCHEDULING
TOD schedules are not part of the Excel 15 W7760C Plant
Controller configuration. TOD schedules are configured and operate in time keeping controllers (W7760A or Q7300H) located on the network.
Fig. 20. Effective occupancy flow chart.
Control loops are assigned to a schedule as part of the time keeping controllers configuration. Occupancy data is transmitted from the time keeping controllers to the W7760C control loop.
NOTE: When a Q7300 uses Schedule Assign, it can not receive a schedule from another source. In this case the Q7300 ignores its own schedule so the outputs are null at that point. If there is no schedule bound to that Q7300, then the outputs go according to its own schedule.
NOTE: T7300F/Q7300H schedules support four events, two occupied and two unoccupied plus TUNCOS.
T7300F/Q7300H schedules do not support standby, special or exception schedules.
23 74-3079
EXCEL 15 W7760C PLANT CONTROLLER
Scheduled occupied, standby and unoccupied setpoint values are required even if no schedule is assigned to a control loop.
The relationship rules apply to setpoint values as follows:
Direct Acting – Occupied must be
≤
Standby
≤
Unoccupied.
Reverse Acting – Occupied must be
≥
Standby
≥
Unoccupied.
If a schedule in another network device is assigned to a control loop, a network signal from the schedule sets the occupancy mode and the setpoint is selected accordingly.
The scheduled occupancy state of a Start/Stop or Control
Loop can be different than the effective occupancy state. The scheduled occupancy is determined by the Time of Day
Schedule to which the loop is assigned. The effective occupancy is determined by a combination of the Time of Day
Schedule, bypass (override) operation, and manual override
from a supervisory device. See Fig. 20.
For information on scheduling, refer to System Engineering for the W7760A Building Manager, form 74-2969. Also refer to
System Engineering for the T7300F/Q7300H Series 2000
Commercial Thermostats and Communicating Subbases, form 63-4365.
OCCUPANCY SENSOR OPERATION
The occupancy sensor function is only applicable when a control loop is configured with a digital input assigned as the occupancy sensor and the control loop is in the occupied state. If the occupancy sensor input for the control loop is not configured the loop operates in the occupied state. If the occupancy sensor input for the control loop is configured and the loop is scheduled for unoccupied or standby state the loop operates in the scheduled state and the occupancy sensor function has no effect. If the occupancy sensor input for the control loop is configured and the loop is scheduled for occupied, the loop checks the status of the occupancy sensor.
If the occupancy sensor is active indicating an occupied space, the loop operates in the occupied state. If occupancy sensor is inactive indicating the space is not occupied, the loop operates in the standby state.
SETPOINT RESET
Setpoint reset uses the reset input to reset (raise or lower) the control loop occupied setpoint. Setpoint reset is only applicable to the occupied mode. The amount of the reset and the range of the reset input used to reset the setpoint are configurable.
The reset input is an AI and can be a physical or remote sensor, an output from another control loop (pseudo point) or a
setpoint. See Fig. 21 and 22. If the input is not configured,
setpoint reset is not applicable to the control loop operation.
Setpoint reset requires program entry of three reset setpoints.
They are the Zero Reset Sensor Value, Max Reset Sensor
Value and Max Reset Amount. See Fig. 21 and 22.
Zero Reset Sensor Value is the reset input value where no reset occurs. (Effective Setpoint equals Occupied Setpoint.)
Max Reset Sensor Value is the reset input value where the maximum reset is achieved. (Effective Setpoint equals
Occupied Setpoint plus Max Reset Sensor Amount.) Max
Reset Amount is the maximum amount the Effective Setpoint can change from the occupied setpoint as the reset input value varies from the Zero Reset Sensor Value to the Max
Reset Sensor Value.
Max
Reset
Amount
+
Setpoint
Reset
-
Max
0
Reset
Amount
Effective Setpoint
Occupied
Setpoint
Effective Setpoint
Zero Reset Max Reset
Reset Sensor Value
Fig. 21. Direct acting setpoint reset.
Max
Reset
-
Setpoint
Reset
+
Max
Reset
Amount
0
Effective Setpoint
Occupied
Setpoint
Effective Setpoint
Zero Reset Max Reset
Reset Sensor Value
Fig. 22. Reverse acting setpoint reset.
Setpoint reset is designed to operate in the energy saving direction, direct acting control loops are reset up from the
However, entering a negative (-) value for the Max Reset
Amount reverses the direction of reset if an application requires. Reset is limited to the Max Reset Amount from the setpoint. The only constraint on the Zero Reset and Max
Reset Sensor values is that they must be within the range of the input. Positive and negative numbers are acceptable if they are in the reset sensor range. The Zero Reset Sensor value can be greater than or less than the Max Reset Sensor value.
Setpoint Reset Calculation
Where:
SP = Occupied Setpoint.
Rst = Max Reset Amount.
Sen
Z
r
= Zero Reset Sensor Value.
Max
r r
= Reset Sensor Input Value.
= Max Reset Sensor Value.
Effective setpoint is equal to:
Direct Acting or
SP
+
Rst
×
Sen
–
Z
------------------------
r
M ax r
–
Z r
Reverse Acting
SP
–
Rst
×
Sen
Max r r
–
–
Z
Z r r
74-3079 24
EXCEL 15 W7760C PLANT CONTROLLER
NOTE: Formulas are only valid for Z
r
≤
SEN
r
≤
Max
r
. The reset amount, Rst, is limited by the unoccupied setpoint value. This means the setpoint will not reset beyond the unoccupied setpoint regardless of the value of Rst, Max Reset Amount. It is necessary to set the unoccupied setpoint to a value that accommodates to the Max Reset Amount, Rst.
DEMAND LIMIT CONTROL
The following information covers only the operation of a
W7760C Plant Controller control loop as a load in a DLC program. Refer to the W7760A Building Manager System
Engineering, form 74-2969 for more information about DLC strategy and configuration. The W7760C Plant Controller control loops uses network commands from other controllers
on the network to initiate a DLC setpoint bump. See Fig. 23.
All demand program parameters are part of the demand program and the DLC setpoint bump remains active for the duration of the DLC shed command from the network. DLC setpoint bump is only applicable in the occupied mode. When a control loop receives a shed command the DLC setpoint bump is added to the occupied effective setpoint. Direct acting control loop setpoints are raised and reverse acting control loop setpoints are lowered by the DLC setpoint bump value. If the control loop has an output greater than 0 percent or on and the main sensor value satisfies the DLC effective setpoint, the outputs are either 0 percent or turned off observing minimum on time and interstage off time requirements for the control loop.
For the single DLC parameter being configured as the DLC
Setpoint Bump.
DLC Setpoint Calculation
Where:
SP = Occupied Setpoint.
Rst = Max Reset Amount.
Reset = Reset Calculation.
DLC = DLC Setpoint Bump.
(For Direct Acting)
IF Rst is positive
THEN
IF (SP + Reset) > (SP + DLC)
THEN (SP + Reset)
ELSE SP + DLC
ELSE (SP + Reset + DLC)*
(For Reverse Acting)
IF Rst is positive
THEN
IF (SP - Reset) < (SP - DLC)
THEN (SP - Reset)
ELSE SP - DLC
ELSE (SP - Reset - DLC)*
* Reset is a negative value.
DLC
Effective
Setpoint
Input
Sensor
Value
Occupied
Effective Setpoint
DLC Shed
Time
Min Recovery
Ramp Rate
Input sensor value equals or exceeds setpoint at end of shed
DLC
Effective
Setpoint
Input
Sensor
Value
Occupied
Effective Setpoint
DLC Shed
Time
Min Recovery
Ramp Rate
Input sensor value less than setpoint at end of shed
When the DLC restores the load (removes the DLC setpoint bump) the effective setpoint is ramped to the occupied setpoint plus reset. The ramp time is minimum recovery ramp rate (refer to Adaptive Intelligent Recovery). If Minimum recovery ramp rate is 0, the ramp rate is the DLC bump value per hour. If the input sensor value is greater than the DLC setpoint, the recovery ramp calculates from the DLC setpoint.
If the input sensor value is less than the DLC setpoint, the setpoint ramp calculates from the input sensor value at the end of the DLC shed. Fig. 24 applies to a direct acting control loop. For a reverse acting control loop the effective setpoint is bumped down and the recovery ramps up. DLC recovery observes the minimum off time and the interstage on time requirements
ADAPTIVE INTELLIGENT RECOVERY
Fig. 23. DLC effective setpoint (direct acting control loop).
Adaptive Intelligent Recovery is a Honeywell proprietary algorithm to minimize energy consumption and assure that comfort conditions are achieved at the beginning of the
scheduled occupancy period. See Fig. 24. The W7760C Plant
Controller control loops use Adaptive Intelligent Recovery for scheduled transitions from unoccupied to occupied, standby to occupied, unoccupied to standby and DLC setpoint bump to occupied operation. The concept of Adaptive Intelligent
Recovery is to ramp the setpoint from the unoccupied or standby setpoint, to the standby or occupied setpoint over a period of time that is based on the recovery capability of the mechanical system. The minimum ramp rate assures that if the mechanical equipment is correctly sized, the occupied temperature will be met at the scheduled occupied time. If the equipment is oversized or the conditions are at partial load, the equipment is cycled off to prevent meeting the occupied setpoint before the scheduled time. By adjusting the ramp rate based on the recovery sensor value, the setpoint ramps to the occupied setpoint at a rate that matches the recovery capability of the mechanical system minimizing energy consumption and reducing equipment cycling. Adaptive
Intelligent Recovery requires four data points to be configured
for the control loop. See Table 9.
25 74-3079
EXCEL 15 W7760C PLANT CONTROLLER
.
UNOCCUPIED
OR STANDBY
SETPOINT
MIN
RECOVERY
RAMP RATE
SCHEDULED
CHANGE OF STATE
STANDBY
OR
OCCUPIED
SETPOINT
MAX
RECOVERY
RAMP RATE
MIN MAX
RECOVERY SENSOR VALUE
TUNCOS M18410
Fig. 24. Adaptive Intelligent Recovery (reverse acting).
Table 9. Adaptive Intelligent Recovery Setpoint Name.
Setpoint Name
Minimum
Recovery
Sensor Value
Maximum
Recovery
Sensor Value
Minimum
Recovery Rate
Maximum
Recovery Rate
Description
The value of the recovery sensor (typically outside air at local design temperature) at which the minimum recovery ramp occurs.
The value of the recovery sensor (typically outside air at no load temperature) at which the maximum recovery ramp occurs.
The recovery rate for the mechanical system
(typically heating or cooling) at design conditions (usually the outside air temperature). This minimum rate of recovery takes the maximum time to get to the new occupied or standby setpoint.
The recovery rate for the mechanical system
(typically heating or cooling) at no load conditions (usually the outside air temperature at which heating or cooling is no longer needed). This maximum rate of recovery takes the minimum time to get to the new occupied or standby setpoint.
NOTE: When used with Adaptive Intelligent Recovery, minimum and maximum apply to the rate of recovery expressed in degrees per hour. The smallest amount of recovery in one hour is minimum recovery. The most recovery in one hour is maximum recovery. For example, a heating plant can be sized for a recovery of 3°F per hour, at 0°F outside air temperature and a recovery of 8°F per hour at 55°F. The minimum recovery rate is 3°F per hour and the maximum recovery rate is 8°F per hour.
The W7760C Plant Controller has no time keeping capability.
When another device on the network has a schedule assigned to a control loop, the device sends network data to the control loop with the current occupancy status, TUNCOS and the next state. The Adaptive Intelligent Recovery routine calculates the setpoint ramp between the minimum and maximum ramp times based on the value of the recovery sensor and executes the recovery process when TUNCOS is equal to or less than the ramp time. Adaptive Intelligent Recovery can be configured to provide a setpoint step change instead of a ramp. This results in the setpoint changing from the unoccupied or standby value, to the standby or occupied value at the time calculated to start the ramp. The stepped recovery provides the functional equivalent of the optimum start operation. If the Adaptive Intelligent Recovery is not configured, the setpoint transitions from unoccupied to standby or occupied in a single step at the scheduled standby or occupied time
INTELLIGENT SETBACK
The W7760C Plant Controller control loop provides for the intelligent setback of the occupied setpoint. This capability is used for energy savings by ramping the effective setpoint from the occupied setting to the standby setting over a fixed period
of time at the end of the occupied period. See Fig. 25.
Intelligent Setback is only applicable if the loops assigned schedule has standby assigned for the end of the occupancy period. The setpoint change for occupied to unoccupied and from standby to unoccupied is a step change that occurs at the scheduled time.
EFFECTIVE
SETPOINT
SCHEDULED
UNOCCUPIED TIME
OCCUPIED
SETPOINT
STANDBY
SETPOINT
UNOCCUPIED
SETPOINT
TUNCOS
SCHEDULED
STANDBY TIME
M18411
Fig. 25. Setback ramp (reverse acting).
If the intelligent setback ramp is a value greater than 0, the intelligent setback is applied. If the value is 0, the transition from occupied to standby is a step change. The transition to unoccupied is always a step change. The ramp time is calculated by dividing the difference between occupied and standby setpoints by the ramp rate.
OCCUPANCY OVERRIDE OPERATION
Manual override can be used to place the control loop effective occupancy state in something other than the scheduled occupancy state. An operator interface (ZL7761A
L
ON
S
TATION
or the S7760A Command Display), a digital input or the bypass operation of another controller on the network
can initiate manual override. See Fig. 26.
The W7760C Plant Controller supports manual override commands for occupied, standby, unoccupied and bypass.
When the control loop is placed in manual occupied, standby or unoccupied operation it operates in the occupancy state selected until manual operation is terminated. When the control loop is placed in bypass operation, a bypass timer is initiated. At the end of the preset bypass time, bypass operation terminates. See Bypass Operation for more information.
NOTE: L
ON
S
TATION
only supports the manual bypass command. The Command Display supports occupied, unoccupied and bypass commands but not standby.
74-3079 26
EXCEL 15 W7760C PLANT CONTROLLER
START
* DEFAULT STATE
MANUAL
OPERATOR
COMMAND
OCCUPIED
STANDBY
UNOCCUPIED
BYPASS
AUTO (NULL) *
THIS FLOW CHART IS A SIMPLIFIED VIEW OF THE
PROCESS FOR THE PURPOSE OF ILLUSTRATION
SET
Man Occupied
= Auto (Null)
SET
Man Occupied
TO MOST
RECENT
COMMAND
IS
Man Occupied
=Auto
?
N
Y
IS
Man Occupied
=Bypass
?
N
Y
IS
Man Occupied
=Unoccupied
?
N
Y
SET
Manual Override
=Unoccupied
IS
Man Occupied
=Standby
?
N
Man Occupied
IS OCCUPIED
Y
SET
Manual Override
=Standby
SET
Manual Override
=Occupied
SHARED
BYPASS
BYPASS
OFF *
IS
Shared Bypass
=Bypass
?
Y
N
IS
Man Occcupied
=Bypass New
?
N
SET
Manual Override
=Bypass
IS
Shared Bypass
=Bypass
?
Y
N
Y
N
IS
Byp Timer
=0
?
Y
N
IS
Man Occupied
=Auto New
?
N
IS
Local Bypass
=Bypass New
?
Y
SET
Byp Timer
=Bypass
Time
MANUAL
OVERRIDE
(FIG. 20)
Y
LOCAL BYPASS
(MOMENTARY
INPUT)
OCCUPIED
STANDBY
UNOCCUPIED
BYPASS
(NULL)
BYPASS
NO ACTION *
M18412
SETPOINT OVERRIDE OPERATION
Fig. 26. Manual override state flow chart (net wins).
Four setpoint overrides can be programmed to override the calculated effective setpoint. If a setpoint override digital input is active, the effective setpoint value is equal to the override setpoint value regardless of any other setpoint settings, calculations or manual occupancy override. If multiple setpoint override inputs are active, the one assigned the highest number is active (setpoint override four has the highest priority). If no setpoint override digital input is active, the effective setpoint is equal to the setpoint determined by the current occupancy mode, setpoint reset, DLC, occupancy sensor and unoccupied bypass.
NOTE: There is no occupancy state indication on operator interface devices that indicates the setpoint override is active. The effective setpoint displays the occupancy state that would be used if no override was in effect.
CONTROL LOOP INPUTS
The control loop has seven control inputs plus four setpoint
override inputs, each has a specific purpose. See Table 10.
27 74-3079
EXCEL 15 W7760C PLANT CONTROLLER
Table 10. Control Loop Inputs.
Input Name
Main Sensor
Bypass Input
Type Description
Analog The input sensor is used in the PID loop to calculate the required output positions. This is also referred to as the primary sensor. This input must be configured to have a control loop that is configured. If a fault (for example: open, short or loss of data) occurs on the main sensor, the control loop stops and all outputs are set to start value (usually 0) percent or off. In L
ON
S
PEC
, changing the main sensor to unconfigured causes all configured data to be set to the unconfigured default values.
Digital The bypass input is used to restore occupied operation during an unoccupied or standby period when a schedule is applied to the control loop. Bypass input is not required for schedule operation.
Refer to Unoccupied State Operation and Standby State Operation for more information.
Reset Sensor Analog This sensor resets the occupied setpoint when the reset schedule is configured. Refer to Setpoint
Reset for more information.
Recovery Sensor Analog This sensor is used to reset the Adaptive Intelligent Recovery setpoint ramp. Refer to Adaptive
Intelligent Recovery for more information.
Occupancy Sensor Digital The occupancy sensor is used to change the setpoint from Standby to Occupied and back. Refer to
Standby mode for more information.
Loop Disable Input Digital This input disables the loop when the input is active (on, true). When the Loop Disable Input is active, minimum on times are observed for any outputs that are on.
CAUTION: The loop is disabled when the input is active. The loop is enabled when the input is
inactive (off, false). Use care when designing the control strategy so that the input logic is correct.
Limit Analog Input Analog An input from a control loop that is configured to act as a high or low limit. Refer to High/Low Limit
Application for more information.
Setpoint Overrides
Digital Input 1
Digital Input 2
Digital Input 3
Digital Input 4
Digital Overrides the control loop calculated setpoint value when the input is active (on, true). Refer to
Setpoint Override for more information.
Only the Main Sensor is required for control loop operation. All other sensors are optional depending on the application that the control loop is configured for.
All input points are selected using the drop down combo list
box. An input can be used by multiple loops. See Table 11 for
input point source information.
Point Source
Physical Inputs
New Digital Input or
New Analog Input
Digital Pseudo Point or
Analog Pseudo Point
Remote
Setpoints (analog only)
UNCONFIGURED
Table 11. Input Point Source Information.
Description
These are input devices that are physically connected to the W7760C controller. The input selection lists all physical input points of the appropriate type (analog or digital) that are configured for the controller.
The control loop treats an analog input that is configured as digital as a digital input.
Opens the appropriate input configuration screen to configure a new physical input that is used for the control loop input. Closing the physical input configuration screen returns the user to the Control Loop
Input Selection screen.
Pseudo Points are the outputs of Start/Stop Loops, Control Loops, Logic Loops and Math Loops within the controller. These loops are created when a loop output is configured. Pseudo Points are automatically named using the loop name with a suffix of the output function. The pseudo point names can not be changed.
Remote points are physical input points and pseudo points created in another controller. Selecting
Remote opens the Remote selection window. The user must select the source controller for the input and
then select the input point from the list provided. Only Remote points of the appropriate type (analog or digital) are displayed.
Setpoints are preset values that can be used as inputs when a fixed value is desired. Setpoints are analog only.
This is the default value and disables the input function. It can also be used to unconfigure a previously configured input.
STARTUP RAMP
The startup ramp function is used to limit a control loop output during a defined startup period. The startup ramp acts as both a high and low limit on the loop output to prevent overdriving the output during the startup process. The startup ramp is defined by the Ramp Time and Startup Value Percentage.
See Fig. 28. Startup occurs when the loop is enabled after power up, controller reset, loop disable input changing to inactive or the end of an unoccupied period when the loop is configured Disable in Unoccupied.
74-3079 28
EXCEL 15 W7760C PLANT CONTROLLER
100%
STARTUP
OUTPUT
VALUE
0%
MINIM
UM O
UTPUT
0 SEC.
OUTPUT
RANGE
TIME
STARTUP
RAMP TIME
Fig. 27. Startup ramp.
M18413
The Startup Value Percentage is the value at which the control loop output is set when the controller is powered up, when the controller is reset, when the loop disable input is active or when the loop configured for Disable in Unoccupied is in the unoccupied state. At the beginning of the startup ramp period the controller output is at the Startup Value Percentage. The
Ramp Time is the minimum time in seconds required for the output to change from the Startup Value output to 100 percent or 0 percent. The ramp time is selected to limit the output over time to prevent overshoot in the controlled precess. The time must match the process lag. When the control loop acquires control during the ramp time, it controls the output between the minimum and maximum output defining the effective output range.
CONTROL LOOP OUTPUTS
A control loop has five outputs, four of which can be configured
as analog or staged. See Table 12 for the control loop outputs.
Output Name
Loop EPID output
Sequence 1 (Heat)
Output
Sequence 2 (Econ)
Output
Sequence 3 (Cool)
Output
Auxiliary Out
Table 12. Control Loop Outputs.
Description
This is the primary output signal for the control loop. The output represents the full throttling range of the control loop. The output can be configured as analog, staged, or pseudo. Refer to PID Control for more information.
The first sequencer output can be used for any application requiring sequenced operation. When used in sequenced space temperature or discharge air applications it is typically the heating output. The output can be configured as analog, staged or pseudo. Refer to Sequencer Operation for more information.
The second sequencer output can be used for any application requiring sequenced operation. When used in sequenced space temperature or discharge air applications it is typically the economizer output. The output can be configured as analog, staged or pseudo. Refer to Sequencer Operation for more information.
The third sequencer output can be used for any application requiring sequenced operation. When used in sequenced space temperature or discharge air applications it is typically the cooling output. The output can be configured as analog, staged or pseudo. Refer to Sequencer Operation for more information.
Functions like the Fan output on commercial thermostats. See Aux Output Operation for more information.
OUTPUT OPERATION
A control loop calculates an output value of 0 to 100 percent for each configured control loop output. Analog outputs will be positioned proportionally to the output value based on the output configuration. Staged outputs are configured with one to four digital outputs. The staging selections made for the
EPID and sequenced outputs are configured for each output
used. Staged output operation is shown in Fig. 28.
Minimum off and on times can be assigned from 0 to 254 minutes. The minimum times apply to all stages configured for the control loop output.
NOTE: The loop disable and manual mode commands do not use the minimum off and on times. On power up and controller reset the minimum off times are initialized to provide an orderly and controlled start up of equipment.
Interstage off and on times can be assigned from 0 to 254 minutes. The interstage times apply to all stages configured for the control loop output. Interstage time is the time lapse required before the next stage can be switched on or off. The time should be set to match the mechanical system response time.
Lead/Lag operation can be set for the stages assigned to a control loop output. Lead/lag operation applies only to the digital outputs assigned to the control loop staged output. If multiple control loop outputs are configured as staged, the lead/lag function operates independently for each. See Table
29 74-3079
EXCEL 15 W7760C PLANT CONTROLLER
Stage 1
OFF
Differential =100%
Differential
Single Stage
Stage 2
Stage 1
Differential = 50%
OFF
OFF
Differential
Differential
ON
2 Stage
ON
ON
Stage 3
Stage 2
Differential = 33.3%
Stage 1
OFF
OFF
Differential
OFF
Differential
ON
3 Stage
Stage 4
Stage 3
Stage 2
Stage 1
Differential = 25%
OFF
OFF
Diff.
Diff.
ON
OFF Diff.
ON
OFF
4 Stage
Differential
ON
Diff.
ON
ON
ON
0 10 20 30 40 50 60 70 80 90 100
Control Loop Output %
Fig. 28. Staged output operation.
Table 13. Lead/Lag Selection And Operation.
Lead/Lag
Selection
First On
First Off
Operation
No Lead/Lag Lead/Lag is not used (this is the default setting). The stages will always be cycled in the same sequence with Stage 1 on first, then Stage 2, then Stage 3 and then Stage
4. Off occurs in the reverse order.
This is a rotating scheme. The first stage on is the first stage that turns off. If all stages are off the first stage on will be the stage following the last stage that was turned off.
Equal Runtime The stage with the lowest amount of runtime is turned on first. In the event two or more stages have equal amounts of runtime, the lowest numbered stage is selected first. The stage with the most runtime is turned off first.
NOTE: If the Lead/Lag Selection is changed while the
W7760C control loop is operating, it continues to use the old selection until all stages are off. The new selection takes effect when the next on cycle occurs.
The W7760C keeps track of runtime on each digital output stage of each control loop to the nearest hour in the runtime file. Internally, runtime is incremented every minute. When an hour has elapsed the runtime value is incremented. If the control loop is configured for equal runtime lead/lag, it makes the decision on what stage to run based on the runtime values. The maximum runtime value that can be stored is
65535 hours with a resolution of one hour. When a runtime value reaches 65535 hours, it stops incrementing. The user needs to clear the file before this time. The runtime file is kept in capacitor backed RAM (CRAM) and mirrored in FLASH memory. Once a day, the file is transferred from CRAM to
FLASH. This saves the runtime file in case of an extended power outage. If the CRAM copy is bad, the runtime file is restored from FLASH memory. If the FLASH copy also is bad, then the runtime file is zeroed. No alarm is reported.
Pseudo output is created for each configured output point. If
an output is being used only as the input to another loop within the W7760C, it can be configured as a pseudo point by assigning the pseudo point name as the output point. The pseudo point name is the loop name_Output and is available in the Output drop down list box for the output being configured.
Aux Output Operation; the Aux (auxiliary) Output is a digital
output that works like the fan output on a commercial thermostat. The Aux output can be configured for either continuous or intermittent operation. This selection applies to occupied, bypass and standby operation. Unoccupied is always intermittent. In continuous operation the output is on continuously, regardless of the operation of the other control loop outputs. In intermittent operation the output is on only when an analog output value is greater than 0 or at least one staged output is on. The Aux output can be configured with minimum off and on times.
CONTROL LOOP PARAMETERS
See Table 14 for control loop parameters.
Table 14. Control Loop Parameters.
Parameter
Throttling
Range
Integral
Time
(Seconds)
Derivative
Time
(Seconds)
Description
The proportional change in the measured variable required to change the control output from 0 to 100 percent. This is expressed in the engineering units of the main input sensor. See
Proportional Control for more information.
Determines the integral gain in a PI or PID loop.
The greater the time in seconds, the less the integral change per second. A setting of 0 eliminates the integral function. See Integral
Control for more information.
Determines the derivative gain in a PID loop.
The greater the time in seconds, the greater the derivative effect per second. See Derivative
Control for more information.
DLC
Setpoint
Bump
Control
Action
The amount the effective setpoint is bumped
(changed) if the loop is given a DLC shed command. A direct acting loop setpoint increases by the Bump value. A reverse acting loop setpoint decreases by the Bump value. See
Setpoints for more information.
Direct Acting or Reverse Acting selection. A direct acting loop output increases as the input increases. A reverse acting loop output decreases as the input increases. See
Proportional Control for more information.
Bias Output bias. The default value of 0 for output bias has no effect. Selecting 50 percent adds 50 percent to the loop output calculation, effectively moving the setpoint to the middle of the throttling range. See Proportional Control for more information.
Analog
Limit Select
Sets the function of the Analog Limit input. See
High/Low Limit Applications for more information.
74-3079 30
EXCEL 15 W7760C PLANT CONTROLLER
SEQUENCER
The sequencer is used to scale the EPID Output into three additional outputs. The outputs can be analog or staged. This function is used when multiple outputs are being controlled in sequence from a single control loop. Up to three outputs can be sequenced. Each output can be analog or staged with one
to four digital outputs. See Fig. 29.
100
75
50
25
0
CL-20
-10
Seq1 Heat
Seq2 Econ
Seq3 Cool
0 20 30 40 50 60 70 80 90 100 110
Control Loop EPID Output
Fig. 29. Sequencer output operation.
A sequencer output is scaled to the selected range as the EPID output changes by the configured amount. An application example is discharge air or space control of a single zone air handling unit. One output is required for heating control and one output is required for cooling control. In this application output Seq1(Heat) is generally used for heating control, output
Seq2 (Econ) is generally used for economizer control. and
Seq3(Cool) is generally used for cooling control. See Fig. 30. It
should be noted that better control performance is obtained using separate control loops for each function.
To configure the sequencer, it is necessary to know what the control loop EPID output represents. In the previous example, if the control loop is configured as direct acting an EPID output of 0 percent would represent a call for full heat and 100 percent world represent a call for full cooling. The individual sequenced output operation is defined by entering the following four values.
Seq Start X Percent:
The value of the EPID output when the sequenced output is starting operation. No sequenced output operation occurs beyond the range defined by the Seq Start X
Percentage and the Seq End X Percentage.
Seq End X Percent:
The value of the EPID output when the sequenced output is stopping operation. No sequenced output operation occurs beyond the range defined by the Seq Start X
Percentage and the Seq End X Percentage.
Seq Start Y Percent:
The value of the sequenced output at the Seq Start X value. Sequenced output is limited to the range defined by the Seq Start Y Percentage and the Seq End Y
Percentage.
Seq End Y Percent:
The value of the sequenced output at the Seq End X value.
Sequenced output is limited to the range defined by the
Seq Start Y Percentage and the Seq End Y Percentage.
Definition of the X and Y Percentage values can be used to sequence outputs that are directly or inversely proportional to the change of the EPID output, and to limit the range of the sequenced output.
HIGH/LOW LIMIT APPLICATIONS
Control loops can be configured for high or low limit applications. High and low limit applications require two control loops, one configured for limit and one configured for
Limit
Sensor
Limit
Control Loop
PID
Limit
Output
Control
Sensor
Primary Control
Loop
PID
High
=Min
Control
Output
CL-18
Limit
Input
Low
=Max
Limit
Fig. 30. High/Low limit control.
The limit loop is configured as a standard control loop with the setpoint at the limit value. The primary control loop is configured with either the high or low limit selected. The limit control loop output is configured as the primary control loop
Limit Input. If the primary control loop is configured as the low limit, the loop output will be the larger of the PID output or the
Limit Input. If configured as the high limit, the loop output will be the smaller of the PID output or the Limit Input. Care must be taken to select direct or reverse acting to insure the limit control loop output is correct. Both the limit control loop and the primary control loop should be set for the same action.
Direct or reverse acting should be selected based on the control application. For more information about direct and reverse acting control, see Proportional Control.
SETPOINT ALARMS
Setpoint alarms can be configured for each control loop.
Setpoint alarms can be configured for high and low alarm conditions. The alarms occur when the primary input sensor value exceeds the programmed (Delta) from the effective setpoint. The alarm thresholds track changes in the setpoint values. Pre and post times can be assigned to the alarms to filter out nuisance alarms.
CONTROL LOOP DISABLE
Each control loop can be disabled with the Loop Disable Input or by manual command from an operator interface. When the loop is disabled the EPID output is set to the Startup Ramp
Start Value. Disable does not observe the minimum off and on times. The control loop is disabled when the Disable Loop input is active (true). The loop is enabled when the input is
31 74-3079
EXCEL 15 W7760C PLANT CONTROLLER
inactive (off, false). Care must be taken in designing the control strategy to insure that the input logic is correct. A control loop can be commanded to the Disable, Auto or
Manual mode from an operator interface. The last mode command received is the mode in effect. When a loop is disabled using an operator interface it remains disabled until it is enabled by an operator interface. Loop disable mode remains in effect if there is a power outage for the duration of the backup capacitor. When power is restored, the EPID output restores the Startup Ramp Start Value.
OUTPUT MANUAL MODE OPERATION
Outputs assigned to control loops can be manually commanded from an operator interface. When a control loop is in manual mode, all outputs associated with the loop are in manual control. Individual analog outputs can be manually positioned from 0 to 100 percent and individual digital outputs can be turned on and off.
IMPORTANT
Be extremely careful when commanding loop outputs manually. All control safeties, software interlocks and minimum off and on times are ignored.
There is a potential for damage to the equipment being controlled.
When a control loop is placed in manual mode, the control loop is turned off and all outputs are positioned as commanded. When the loop is returned to Auto operation, it is reinitialized. Manual mode remains in effect until the output is commanded to automatic mode. Manual mode remains in effect if there is a power outage for the duration of the backup capacitor. When power is restored the output immediately resumes the manually commanded state without delay.
CONTROL LOOP OUTPUT CONFIGURATION DATA
Control loops have output configuration data. Two methods of controlling equipment that affects the controlled sensor are modulating and stages. Modulating controls a valve or damper that varies the output capacity based on a analog signal. Stages control equipment that has two states, on and off. The primary analog output of the control loop can be used as is or be sent to a sequencer to control multiple analog outputs or stages.
The output configuration data is:
— Analog primary output of the EPID (onboard or remote).
— Analog Sequence 1 output (onboard or remote).
— Analog Sequence 2 (onboard or remote).
— Analog Sequence 3 (onboard or remote).
— Digital Outputs: for controlling stages (onboard or remote).
— Up to four digital outputs can be assigned to each of the four analog outputs (16) total.
— Typically the user either assigns up to four digital outputs to the primary analog output or up to 12 digital outputs to the three sequenced analog outputs.
— Staging intervals are equally fixed across the 0 to 100 percent output band, with fixed hystersis.
— Digital Auxiliary output (onboard or remote).
Logic Loops
The W7760C Plant Controller supports 32 independent logic loops. Logic loops can be used for on/off control, control interlocks, analog switching and other uses. Logic loops can be used independently or cascaded with control loops, math loops or other logic loops. Logic loops are run once per second starting with logic loop 1, then logic loop 2 and sequentially until all active loops are run.
Each logic loop consists of three logical AND functions, three
Analog Compare Digital Output (ACDO) functions, one logical
OR function and one Digital Compare Analog Output (DCAO) function. Each logic loop can use up to eight AIs and 16 DIs to determine the output state for one AO and one DO. See
Analog inputs configured as digital are used by logic loops as digital inputs. Digital inputs are read as active equals true and inactive equals false. Analog inputs are floating point decimal.
Inputs for the ACDO, AND, OR and DCAO functions can be physical inputs, remote inputs, setpoints, pseudo points or outputs from logic functions in the same logic loop in which they are configured.
ANALOG COMPARE DIGITAL OUTPUT (ACDO)
Each logic loop can be configured with up to three logical
ACDO functions. See Fig. 32. ACDO compares one analog
input against another analog input. The result is a digital output.
The analog inputs for an ACDO can be selected from analog physical points, remote points, setpoints, pseudo points or outputs from control loops, logic loops or math loops. The digital output can be used only by other logic functions within the same logic loop.
ACDO can be programmed with a deadband that is subtracted from the analog input AI2 value before making the comparison when the output is true. The deadband is expressed in the units of AI2. ACDO can be programmed with pre-delay and post-delay in seconds. Pre-delay requires the compare statement to be true for the programmed time before the output is set true. Post-delay requires the compare statement to be false for the programmed time before the output is set false. ACDO logic can be expressed for each of the following type comparisons:
Greater Than (>)
IF AI1 > AI2 for time > pre-delay
THEN output = TRUE.
ELSE IF AI1 < (AI2 - deadband) for time > post-delay
THEN output = FALSE
ELSE output = previous state.
Less Than (<)
IF AI1 < AI2 for time > pre-delay
THEN output = TRUE.
ELSE IF AI1 > (AI2 - deadband) for time > post-delay
THEN output = FALSE
ELSE output = previous state.
Equal To (=)
IF AI1
≤
AI2 AND AI1 post-delay
≥
(AI2 - deadband) for time > pre-delay
THEN output = TRUE.
ELSE IF AI1 > AI2 OR AI1 < (AI2 - deadband) for time >
THEN output = FALSE
ELSE output = previous state.
NOTE: The equal to (=) is fuzzy equal. The deadband is used to make the equal comparison. If the value of
AI1 is within the deadband of AI2 the comparison is considered to be equal (TRUE).
74-3079 32
EXCEL 15 W7760C PLANT CONTROLLER
Logic Loop
A-1
A-2
ACDO DO
A
Analog Input
8
Max
A
Analog Input
A-1
A-2
A-1
A-2
ACDO
ACDO
DO
DO
DO
D-1
D-2
D-3
D-4
D-5
D-6
Logical
OR
Analog Output
A
D-1
D-2
D-3
Logical
AND
D
Digital Input
16
Max
D
Digital Input
D-1
D-2
D-3
Logical
AND
DO
D-1
A-1
A-2
DCAO Digital Output
D
D-1
D-2
D-3
Logical
AND
DO
LL-1
LOGICAL AND
A1
A2
ACDO
>
< or
=
D Out
Fig. 32. ACDO.
Each logic loop can be configured with up to three logical AND functions. The AND function compares three digital inputs to determine the logic state of the digital output. The output is true
D1
D2
D3
AND
D Out
LL-03
LL-02
if and only if all input states are true. See Fig. 33.
D1
D2
D3
Logic Symbol
Fig. 31. Logic loop schematic
Pre-delay requires the AND statement to be true for the programmed time before the output is set TRUE. Post-delay requires the AND statement to be false for the programmed time before the output is set FALSE.
Fig. 33. Logical AND function.
The digital inputs to an AND function can be any combination of digital physical points, remote points, pseudo points or outputs from logic functions within the same logic loop. The output from an AND function can only be used by another logic function within the same logic loop. An unconfigured input to an AND function is set to TRUE. Each digital input of an AND function can be assigned as NOT, this means the
AND function reads an input state of TRUE as FALSE and an input state of FALSE as TRUE. The AND function can be programmed with pre-delay and post-delay in seconds.
33
AND logic can be stated as follows:
IF (DI1 AND DI2 AND DI3) =TRUE for time > pre-delay
THEN output = TRUE.
ELSE IF (DI1 OR DI2 OR DI3) =FALSE for time>post-delay
THEN output = FALSE
ELSE output = previous state.
See Table 15 for an AND function logic table.
Table 15. AND Function Logic Table.
T
F
T
T
Input State
DI1 DI2 DI3
T
F
T
T
T
T
F
F
F
T
F
T
F
F
T
F
F
F
T
F
Output
T
F
F
F
F
F
F
F
NOTE: A NOT function on an input reverses the input logic state.
74-3079
EXCEL 15 W7760C PLANT CONTROLLER
LOGICAL OR
There is one logical OR function in each logic loop. The output of the OR function is the digital output for the logic loop. The
OR function compares six digital inputs to determine the logic state of the digital output. The output is true if one or any
combination of inputs is true. See Fig. 34 for Logical OR
function.
D1
D2
D3
D4
D5
D6
OR
D Out
LL-04
D1
D2
D3
D4
D5
D6
Logic Symbol
Fig. 34. Logical OR function.
The digital inputs to an OR function can be any combination of digital physical points, remote points, pseudo points or outputs from logic functions within the same logic loop. The output from an OR is the digital output from the logic loop and can be assigned to a physical or remote digital output and/or used as an input to one or more control loops and/or logic loops. An unconfigured input to an OR function is set to
FALSE. Each digital input of an OR function can be assigned as NOT, this means the OR statement reads the input state of
FALSE as TRUE and an input state of TRUE as FALSE. The
OR function can be programmed with pre-delay and postdelay in seconds. Pre-delay requires the OR statement to be true for the programmed time before the output is set TRUE.
Post-delay requires the OR statement to be false for the programmed time before the output is set FALSE.
OR logic can be stated as follows:
IF (DI1 OR DI2 OR DI3 OR DI4 OR DI5 OR DI6) =TRUE for time > pre-delay
THEN output = TRUE.
ELSE IF (DI1 AND DI2 AND DI3 AND DI4 AND DI5 AND
DI6) =FALSE for time>post-delay
THEN output = FALSE
ELSE output = previous state.
See Table 16 for an OR function logic table (partial for
illustration).
Table 16. OR Function Logic Table.
F
T
T
F
F
F
F
Digital Input State
DI1 DI2 DI3 DI4 DI5 DI6
T
F
F
T
F
F
F
F
F
F
F
F
F
F
F
F
T
F
F
F
F
T
F
F
F
F
T
F
F
T
F
F
F F
T T
F T
F F
T T
F F
F
T
F
OR
Output
T
T
T
T
T
T
F
T
T
NOTE: A NOT function on an input reverses the input logic state.
DIGITAL COMPARE ANALOG OUTPUT (DCAO)
There is one logical DCAO function in each logic loop. The output of the DCAO function is the analog output for the logic loop. The DCAO selects one of two analog input values to be
the analog output value. See Fig. 35.
D
A1
A2
DCA0
A Out
LL-05
Fig. 35. DCAO function.
All inputs for a DCAO function must be configured or the function will not operate. The digital input to a DCAO function can be a digital physical point, remote point, pseudo point or an output from a logic function within the same logic loop. The analog inputs can be selected from analog physical points, remote points, setpoints or pseudo points. The output from a
DCAO is the analog output from the logic loop and can be assigned to a physical or remote analog output and/or used as an input to one or more control loops, logic loops, and/or math loops.
The DCAO function can be programmed with pre-delay and post-delay times in seconds. Pre-delay is the time the digital input must be TRUE before the output switches to AI1. Postdelay is the time the digital input must be FALSE before the output switches to AI2.
The operation of the DCAO can be expressed as:
IF DI1 = TRUE for time > pre-delay
THEN A Out = AI1
ELSE IF DI1 = FALSE for time > post-delay
THEN A Out = AI2
ELSE A Out = previous output.
Math Functions
The Plant Controller supports 30 general math functions.
Math functions are used to make special computations that can be required in a control strategy. Math functions are used as inputs to control loops, logic loops and to other math functions. An input to a math function can be a physical or remote point value, a pseudo point, a setpoint, a output of a control or logic loop, or an output of a math function.
Math functions are executed once every second starting with math function 1, then 2 and sequentially for all configured math functions. Each math function except square root and enthalpy can be configured to operate using inputs A1 through
A6. Each math function consists of one of eight math operands. AIs can be any floating point value available from physical inputs, remote points, setpoints or pseudo points.
The math function result is an analog pseudo point that can be used with control loops, logic loops and math loops in the same W7760C controller. Math functions can not be directly assigned to a physical or remote output. Network Special is a unique case of math functions that is used with network
points. See Fig. 36 for a math function loop schematic.
74-3079 34
EXCEL 15 W7760C PLANT CONTROLLER
A2
A3
A4
A5
A6
A1
Math Function
A Output
Operand
Max, Min, Ave,
+, -, x, /, ,
Enthalpy
ML-01
MATH FUNCTION OPERATORS
See Table 17 for a description of the math function operators.
Fig. 36. Math loop schematic.
Table 17. Math Function Operators.
Operand Description Comments
Minimum Output equals Minimum value of AI1, AI2, AI3, AI4, AI5, AI6. An input is skipped if it is not configured or is invalid.
Maximum Output equals Maximum value of AI1, AI2, AI3, AI4, AI5, AI6. An input is skipped if it is not configured or is invalid.
Average Output equals Average value of configured inputs AI1, AI2,
AI3, AI4, AI5, AI6.
An input is skipped if it is not configured or is invalid.
Square
Root
Output equals Square Root of the absolute value of AI1.
Add Output equals the Sum of AI1, AI2, AI3, AI4, AI5, AI6.
If AI1 is negative, it is converted to positive and then the square root of the value is taken. Result is
Float_Invalid if AI1 is invalid.
It makes no difference which inputs are configured, typically AI1 is configured then AI2 and the rest in sequence. Result is Float_Invalid if a configured input is invalid.
Subtract
Multiply
Divide
Output equals AI1 - AI2 - AI3 - AI4 - AI5 - AI6. The ordinal position must be observed.
Output equals AI1 x AI2 x AI3 x AI4 x AI5 x AI6.
AI1 must be configured. If AI1 is configured, it makes no difference which other AIs are configured. Typically they are in sequence AI2 through AI6. Result is
Float_Invalid if a configured input is invalid.
It makes no difference which inputs are configured, typically AI1 is configured then AI2 and the rest in sequence. Result is Float_Invalid if a configured input is invalid.
Output equals AI1
÷
AI2
÷
AI3
÷
AI4
÷
AI5
÷
AI6. The ordinal position must be observed.
AI1 must be configured. If AI1 is configured, it makes no difference which other AIs are configured. Typically they are in sequence AI2 through AI6. Divide by zero sets the result to Float_Invalid. Result is Float_Invalid if a configured input is invalid.
Enthalpy Output (kJ/kg) equals Enthalpy in SI units.
AI1 equals the temperature in °C.
AI2 equals the percentage of Relative Humidity.
Result is Float_Invalid if either of the two inputs are invalid.
NOTE: This calculation is SI (metric).
IMPORTANT
Use care when observing the operation of the engineering units for the input point. Actual values used in the math functions are in SI. SI to Imperial unit conversion can yield unexpected results especially when working with temperature, enthalpy and airflow.
For example:
1. °F + Delta °F = °F.
2. °F - °F = Delta °F.
3. °F - Delta °F = °F
4. A case that does not work is °F +°F.
For imperial units, 68°F +68°F = 136°F.
Note that the SI equivalent is not the same:
20°C + 20°C = 40°C which is 104°F.
A math function adding 68°F to 68°F has a result of
104°F.
35
MATH FUNCTION NETWORK SPECIAL
Six network special math functions are provided to work with network points. Three math functions are available for temperature points (space or room temperatures from any
Excel 10 controllers) and three for terminal load points
(terminal loads from W7751 VAV box controllers). Each math function is limited to six source points and the operators are limited to Minimum, Maximum and Average. The network special math function is then configured by selecting the
W7760C network input point (it can be renamed if desired) and selecting the math operator (Minimum, Maximum or
Average), and then selecting up to six inputs.
I/O Configuration
The Plant Controller can support both its onboard I/O and its remote I/O. The remote I/O capability, from up to three RIOs, is 24 DOs, 12 DIs and 18 AIs. All inputs can be used by multiple control loops. Outputs can only be commanded by one control loop.
74-3079
EXCEL 15 W7760C PLANT CONTROLLER
REMOTE POLL POINTS
Use remote poll points for control loop inputs, start/stop loop inputs, math or logic functions. The Plant Controller supports a maximum of 20 remote inputs.
APPLICATION STEPS
Overview
The application steps shown in Table 18 are planning
considerations for engineering an Excel 15 W7760C Plant
Controller. These steps are guidelines intended to aid understanding of the product I/O options, bus arrangement choices, configuration options, and the role of the W7760C
Plant Controller in the overall EXCEL 5000
SYSTEM architecture.
OPEN™
Step No.
1
2
3
6
7
4
5
Table 18. Application Steps.
Plan the System.
Description
Determine Other Bus Devices Required.
Lay Out Communications and Power Wiring.
Prepare Wiring Diagrams.
Order Equipment.
Configure Controllers.
Troubleshooting.
Step 1. Plan the System
Plan the use of the W7760C Controllers according to the job requirements. Determine the location, functionality and sensor or actuator usage. Verify that the sales estimate of the number of Excel 15/10 Controllers, T7300F/Q7300Hs, Command
Displays, Wall Modules, and other required items is correct.
Also check the number and type of output actuators and other required accessories.
When planning the system layout, consider potential expansion possibilities to allow for future growth. Planning is very important to be prepared for adding HVAC systems and controllers in future projects.
The T7770A or T7770D Wall Modules (Remote setpoint input not supported) can be installed as either hardwired I/O only devices or additional wiring can be run to them (for the
L
ON
W
ORKS
Bus). This allows a portable PC with the L
ON
S
PEC configuration software to have access to the L
ON
W
ORKS
Bus.
The application engineer needs to determine how many
T7770 wall modules are required. All T7770 Wall Modules, except the T7770A1006 and the T7770A1014, can be connected via the L
ON
W
ORKS
Bus network access jack. Also the application engineer needs to know how many T7770s without L
ON
W
ORKS
Bus network connections are being installed on the job, and then clearly document which wall modules (if any) have network access. This information is required during installation to ensure that the proper number and type of wires are pulled to the wall modules and the building operators will know where they can plug in to the
L
ON
W
ORKS
Bus network with a portable PC.
Refer to Step 4. Prepare Wiring Diagrams for details.
The FTT communication wiring, (L
ON
W
ORKS
Bus) between controllers is a free topology scheme that supports T-tap, star, loop, and/or bus wiring. Refer to the L
ON
W
ORKS
Bus Wiring
Guidelines form, 74-2865 for complete description of network topology rules. See Application Step 3. Lay Out
Communications and Power Wiring for more information on bus wiring layout, and see Application Step 4. Prepare Wiring
Diagrams, for wiring details.
The application engineer must review the Direct Digital
Control (DDC) job requirements. This includes the Sequences of Operation for the W7760C Controllers, and for the system as a whole. Usually there are variables that must be passed between the W7760C Controllers and other Excel 10 controller(s) that are required for optimum system wide operation. Typical examples are the TOD, Occ/Unocc signal, the outdoor air temperature, the demand limit control signal, and the smoke control mode signal.
It is important to understand these interrelationships early in the job engineering process to ensure implementation when configuring the controllers. (Refer to the L
ON
S
PEC
ZL7760A software Help for configuring information on the W7760C,
W7751B,D,F,H, W7750A/B, W7761, W7753 Controllers and the T7300F/Q7300H Series 2000 Commercial Thermostats and Communicating Subbase.)
Step 2. Determine Other Bus Devices
Required
A maximum of 120 controller nodes can communicate on a single L
ON
W
ORKS
Bus segment. Each L
ON
W
ORKS
Bus device constitutes one node.
Each L
ON
W
ORKS
Bus segment is set up with seven unused nodes to allow portable PCs and software tools to be connected to the L
ON
W
ORKS
Bus at the same time. Table 19
summarizes the L
ON
W
ORKS
Bus segment configuration rules.
Table 19. L
ON
W
ORKS
Bus Configuration Rules
And Device Node Numbers.
One L
ON
W
ORKS
Bus Segment Maximum Number of Nodes Equals 127
Ports for tools and portable PC access
7 nodes
Maximum number or Excel
15s/10s and
Q7300Hs
(For configured controllers and devices with a network schedule:)
Up to 4 Excel 15 Building Managers (each
W7760A can use up to 3 RIO Devices).
A total of up to 116 W7760Cs, Excel 10
VAV IIs, CVAHUs UV Controllers, RIO
Devices, Command Displays or Q7300H
Communicating Subbases.
If there are over 60 controllers or devices on a bus, use a Repeater (up to 60 nodes on each side.
Total 127 nodes
74-3079 36
EXCEL 15 W7760C PLANT CONTROLLER
NOTE: For a remote connection using modems, set the
SLTA 10 (FTT) DIP switch numbers two and six to on
(up) and connect the SLTA 10 to the modem using a male DB-9 to male DB-25 cable. This cable should be wired from the DB-9 end to the DB-25 end as follows:
Pin 2 toPin 2
Pin 3 toPin 3
Pin 4 toPin 8
Pin 5 toPin 7
Pin 6 toPin 20 and 4
Refer to the L
ON
W
ORKS
Bus Wiring Guidelines form, 74-2865 for complete description of network topology rules and the maximum wire length limitations. If a longer L
ON
W
ORKS
Bus segment is required, a Q7740A 2-Way or Q7740B 4-Way
Repeater can be added to extend its length. Each network segment can have a maximum of one repeater.
All L
ON
W
ORKS
Bus segments require the installation of a
209541B Termination Module for a singly terminated
L
ON
W
ORKS
Bus or two 209541B Termination Modules for a doubly terminated L
ON
W
ORKS
Bus. For more details on
L
ON
W
ORKS
Bus termination, refer to the L
ON
W
ORKS
Bus
Wiring Guidelines form, 74-2865, or see Application Step 3.
Lay Out Communications and Power Wiring, and the
L
ON
W
ORKS
Bus Termination Module subsection in Application
Step 4.
Step 3. Lay Out Communications and Power
Wiring
Communications
IMPORTANT
If the W7760C is used on Heating and Cooling
Equipment (UL 1995, U.S. only) and the trans-
former primary power is more than 150 volts, connect the transformer secondary to earth ground. See
Fig. 37. For these applications, only one W7760C
Controller can be powered by each transformer.
The L
ON
W
ORKS
Bus communications bus is a 78 kbps serial link that uses transformer isolation and differential Manchester encoding. Guidelines for communications wiring are as follows:
— All field wiring must conform to local codes and ordinances.
— Approved cable types for L
ON
W
ORKS
Bus communications wiring is Level IV 22 AWG (0.34 mm
2
) plenum or nonplenum rated unshielded, twisted pair, solid conductor wires.
For nonplenum areas, U.S. part AK3781 (one pair) or U.S. part AK3782 (two pair) can be used. In plenum areas, U.S. part AK3791 (one pair) or U.S. part AK3792 (two pair) can be used. Additionally, Echelon approved cable can be used.
Contact Echelon Corp. Technical Support for the recommended vendors of Echelon approved cables.
— Unswitched 24 Vac power wiring can be run in the same conduit as the L
ON
W
ORKS
Bus cable.
— Do not bundle output wires with sensor, digital input, or communications L
ON
W
ORKS
Bus wires.
— Do not use different wire types or gauges on the same
L
ON
W
ORKS
Bus segment. Using different wire types or gauges can result in line impedance changes that can cause unpredictable reflections on the L
ON
W
ORKS
Bus.
— In noisy (high EMI) environments, avoid wire runs parallel to noisy power cables, motor control centers, or lines containing lighting dimmer switches, and keep at least 3 in.
(76 mm) of separation between noisy lines and the
L
ON
W
ORKS
Bus cable.
— Each L
ON
W
ORKS
Bus one segment containing up to 120
(see Table 18) Excel 15/10 Controllers, T7300F/Q7300Hs,
Command Displays requires the installation of a 209541B
Termination Module for a single terminated L
ON
W
ORKS
Bus or two 209541B Termination Modules for a doubly terminated L
ON
W
ORKS
Bus. For more details on
L
ON
W
ORKS
Bus termination, refer to the L
ON
W
ORKS
Bus
Wiring Guidelines 74-2865.
— Make sure that neither of the L
ON
W
ORKS
Bus wires is grounded.
— If a longer L
ON
W
ORKS
Bus segment is required, a Q7740A
2-way or Q7740B 4-way Repeater can be added to extend its length. Each network segment can have a maximum of one repeater.
HONEYWELL
W7760C
PLANT
CONTROLLER
CONNECT
POWER TO
TERMINALS
45 AND 47
TRANSFORMER
EARTH
GROUND
M17295
Fig. 37. Transformer power wiring details for one W7760C used in UL 1995 equipment (U.S. only).
37 74-3079
EXCEL 15 W7760C PLANT CONTROLLER
NOTE: If a 209541B Termination Module is required at a
W7760C, connect two of the three termination module wires to the L
ON
W
ORKS
Bus terminals. Selecting the appropriate two wires depends on the L
ON
-
W
ORKS
Bus network topology. Refer to the L
ON
-
W
ORKS
Bus Wiring Guidelines 74-2865, and the
Excel 10 FTT Termination Module Installation
Instructions 95-7554. For example, if using a doubly terminated daisy-chained bus topology the devices are on either end of a L
ON
W
ORKS
Bus wire run, mount the termination module on the appropriate ter-
HONEYWELL
W7760C
PLANT
CONTROLLER
HONEYWELL
W7760C
PLANT
CONTROLLER
PART NO.
209541B
TERMINATION
MODULE
EARTH
GROUND
PART NO.
209541B
TERMINATION
MODULE
EARTH
GROUND
M17296
NOTE: If terminals 13 and 14 on the L
ON
W
ORKS
ON
W
ORKS
Bus to have a break in it. To prevent the break from occurring, attach jumpers.
Bus are used as inputs and 15 and 16 are used as outputs and the snap-on cover/electronics assembly is removed from the subbase, then this causes the
L
Fig. 38. Termination modules (doubly terminated L
ON
W
ORKS
Bus).
Connect the L
ON
W
ORKS
Bus cable to the W7760C communication terminals 13 and 14 or 15 and 16. For daisy- chain wiring, see form 74-2865.
Wire to the terminal blocks as follows:
1. Strip 1/2 in. (13 mm) insulation from the conductor.
2. If using a single wire in the required terminal location, cut the wire to 3/16 in. (5 mm) insert and tighten the screw to complete the termination.
3. If two or more wires are being inserted into one terminal location, twist the wires together a minimum of three turns before inserting them.
4. Cut the twisted end of the wires to 3/16 in. (5 mm) before inserting them into the terminal and tightening the screw.
5. Pull on each wire in all terminals to check for good mechanical connection.
NOTE: When attaching two or more wires, other than 14
AWG (2.0 mm
2
), to the same terminal, twist wires
together. See Fig. 39. Deviation from this rule can
result in improper electrical contact.
74-3079 38
1.
STRIP 1/2 IN. (13 MM)
FROM WIRES TO
BE ATTACHED AT
ONE TERMINAL.
1/2
(13)
2.
TWIST WIRES
TOGETHER WITH
PLIERS (A MINIMUM
OF THREE TURNS).
EXCEL 15 W7760C PLANT CONTROLLER
Fig. 40 and 41 show two typical L
ON
W
ORKS
Bus segment network topologies.
ON
W
ORKS
Bus segment network topology with one doubly terminated L
ON
W
ORKS
Bus segment
that has 120 nodes or less. Fig. 41 shows a typical L
ON
W
ORKS
Bus segment network with one singly terminated L
ON
W
ORKS
Bus segment that has 120 nodes or less. The bus configuration is set up using the L
ON
S
PEC
configuration tool.
NOTE: For specific wiring details, see Step 4. For wall module wiring, use U.S. part AK3782 (non-plenum) or
U.S. part AK3792 (plenum). For an L
ON
W
ORKS
Bus that is a doubly terminated daisy-chain, these cables contain two twisted pairs (one for the run to the wall module, and one for the run back to the controller) for ease of installation.
3.
CUT TWISTED END OF WIRES TO 3/16 IN. (5 MM)
BEFORE INSERTING INTO TERMINAL AND
TIGHTENING SCREW. THEN PULL ON EACH
WIRE IN ALL TERMINALS TO CHECK FOR
GOOD MECHANICAL CONNECTION.
M17207
Fig. 39. Attaching two or more wires at terminal blocks.
EXCEL 10
UV
1 4 8 12 16
EXCEL 15
W7760A
17 23 30 31 37 44
S7760
Back Select
EXCEL 15
W7760C
PART NO. 209541B
TERMINATION
MODULES
L
ON
W
ORKS
BUS
EXCEL 10 VAVII
1 4 8 12 16
EXCEL 15
W7760A
17 23 30 31 37 44
1 4 8 12 16
EXCEL 15
W7760A
17 23 30 31 37 44
T7300F/
Q7300H
EXCEL 15
W7760C
L
ON
W
ORKS
BUS
EXCEL 10
VAVII
EXCEL 10
RIO
EXCEL 10
CVAHU
1 2 3
EXCEL 15
W7760C
(SHARED)
T7770
UP TO 120
TOTAL NODES
(WITH A Q7740
REPEATER)
EXCEL 10
CVAHU
EXCEL 10
RIO
EXCEL 10
UV
EXCEL 10
RIO
EXCEL 10
CVAHU
T7770s WITH NO
L
ON
W
ORKS
BUS ACCESS
T7770 T7770
T7770
T7770
JACK FOR
OPERATOR
TERMINAL
L
ON
W
ORKS
BUS
I/O CONNECTIONS
Fig. 40. Wiring layout for one doubly terminated daisy-chain L
ON
W
ORKS
Bus segment.
M14519
39 74-3079
EXCEL 15 W7760C PLANT CONTROLLER
EXCEL 10
CVAHU
T7770
L
ON
W
ORKS
BUS ACCESS
EXCEL 10
R I 0
L
ON
W
ORKS
BUS SEGMENT
T7300F/Q7300H
EXCEL 10
CVAHU
EXCEL 10 VAVII
EXCEL 15
W7760C
EXCEL 15
W7760C
1 4 8 12 16
EXCEL 15
W7760A
17 23 30 31 37 44
EXCEL 10
R I 0
EXCEL 10
UV
S7760
Back Select
PART NO. 209541B
TERMINATION
MODULE
EXCEL 10
VAVII
EXCEL 10
CVAHU
EXCEL 10
UV
EXCEL 10
CVAHU
T7770
L
ON
W
ORKS
BUS
ACCESS
M14520
Fig. 41. Wiring layout for one singly terminated L
ON
W
ORKS
Bus segment
Power
A power budget must be calculated for a W7760C to determine the required transformer size for proper operation.
A power budget is simply the summing of the maximum power draw ratings (in VA) of all the devices to be controlled by the
W7760C. This includes the W7760C itself, the equipment actuators (ML6161, or other motors) and various contactors and transducers.
The Excel 15 System example requires 41.9 VA of peak power; therefore, a 75 VA AT88A Transformer could be used to power one Excel 15 Systems of this type, or a 100 VA
AT92A Transformer could be used to power two of these Plant
Controllers and meet NEC Class 2 restrictions (no greater than 100 VA). See Fig. 44 and 45 for illustrations of power
wiring details. See Table 20 for VA ratings of various devices.
Table 20. VA Ratings For Transformer Sizing.
POWER BUDGET CALCULATION EXAMPLE
The following is an example power budget calculation for a typical W7760C Excel 15 Plant Controller.
Assume a W7760C unit with a fan, two stages of D/X cooling, modulating steam valve for heating, and modulating economizer dampers. The power requirements are:
Device
Excel 15 W7760C
Plant Controller
VA Information Obtained from
18.0 W7760C Specification Data
ML6161 Damper
Actuator
R8242A Contactor fan rating
D/X Stages
M6410A Steam
Heating Coil Valve
2.2 TRADELINE
Catalog
21.0 TRADELINE
Catalog inrush rating
0.0 NOTE: For example, assume the cooling stage outputs are wired into a compressor control circuit and has no impact on the budget.
0.7 TRADELINE
24 Vac
Catalog, 0.32A at
TOTAL 41.9
Device
W7760C
ML6161A/B
R8242A
R6410A
MMC325
ML684
ML6464
ML6474
ML6185
Description
Excel 15 W7760C Plant Controller
Damper Actuator, 35 lb-in.
Contactor
Valve Actuator
Pneumatic Transducer
Versadrive Valve Actuator
Damper Actuator, 66 lb-in.
Damper Actuator, 132 lb-in.
Damper Actuator SR 50 lb-in.
For contactors and similar devices, the in-rush power ratings should be used as the worst case values when performing power budget calculations. Also, the application engineer must consider the possible combinations of simultaneously energized outputs and calculate the VA ratings accordingly.
The worst case, that uses the largest possible VA load, should be determined when sizing the transformer.
VA
18.0
2.2
21.0
0.7
5.0
12.0
3.0
3.0
12.0
Each W7760C requires 24 Vac power from an energy-limited
Class II Power Source. To conform to Class II restrictions (U.S. only), transformers must not be larger than 100 VA. A single transformer can power more than one W7760C Controller. Fig.
42 shows power wiring details for a single device and Fig. 43
shows multiple devices using one transformer.
74-3079 40
EXCEL 15 W7760C PLANT CONTROLLER
IMPORTANT
Use the heaviest gauge wire available, up to 14
AWG (2.0 mm
2
mm
2
) with a minimum of 18 AWG (1.0
), for all power and earth ground wiring.
Screw type terminal blocks are designed to accept only one 14 AWG (2.0 mm
2
) conductor. Two or more wires that are 14 AWG (2.0 mm
2
) can be connected with a wire nut. Include a pigtail with this wire group and attach the pigtail to the terminal block.
NOTES: Guidelines for power wiring are as follows:
— For multiple controllers operating from a single transformer, the same side of the transformer secondary must be connected to the same power input terminal in each device. The earth ground terminal (W7760C Terminal 49) must be connected to a verified earth ground for each
controller in the group. See Fig. 42 and 43. Controller
configurations are not necessarily limited to two devices, but the total power draw including accessories cannot exceed 100 VA when powered by the same transformer
(U.S. only).
— All loads on a W7760C must be powered by the same transformer that powers the W7760C.
— Keep the earth ground connection (W7760C Terminal 49)
wire run as short as possible. Refer to Fig. 42 and 43.
— Do not connect earth ground to the W7760C digital or analog ground terminals (2, 5, 8, 11, 18, 21, 24, 27, 29, 30,
44, 51, 54 and 57). Refer to Fig. 42 and 43.
— Unswitched 24 Vac power wiring can be run in the same conduit as the L
ON
W
ORKS
Bus cable.
— Maintain at least a 3 in. (76 mm) separation between Triac outputs and L
ON
W
ORKS
Bus wiring throughout the installation.
HONEYWELL
W7760C
PLANT
CONTROLLER
CONNECT
POWER TO
TERMINALS
45 AND 47
TRANSFORMER
EARTH
GROUND
Fig. 42. Power wiring details for one
W7760C per transformer.
M17293A
41 74-3079
EXCEL 15 W7760C PLANT CONTROLLER
HONEYWELL
W7760C
PLANT
CONTROLLER
HONEYWELL
W7760C
PLANT
CONTROLLER
CONNECT
POWER TO
TERMINALS
45 AND 47
TRANSFORMER
EARTH
GROUND
EARTH
GROUND
M17294A
Fig. 43. Power wiring details for two W7760Cs per transformer.
Line Loss
Excel 15 Controllers must receive a minimum supply voltage of 20 Vac. If long power or output wire runs are required, a voltage drop due to Ohms Law (I x R) line loss must be considered. This line loss can result in a significant increase in total power required and thereby affect transformer sizing.
The following example is an I x R line-loss calculation for a
200 ft. (61m) run from the transformer to a W7760C Controller drawing 37 VA using two 18 AWG (1.0 mm
2
) wires.
The formula is:
Loss = [length of round-trip wire run (ft.)] X [resistance in wire (ohms per ft.)] X [current in wire (amperes)]
From specification data:
18 AWG twisted pair wire has 6.52 ohms per 1000 feet.
Loss = [(400 ft.) X (6.52/1000 ohms per ft.)] X
[(37 VA)/(24V)] = 4.02 volts
This means that four volts are going to be lost between the transformer and the controller; therefore, to assure the controller receives at least 20 volts, the transformer must output more than 24 volts. Because all transformer output voltage levels depend on the size of the connected load, a larger transformer outputs a higher voltage than a smaller one
for a given load. Fig. 44 shows this voltage load dependence.
In the preceding I x R loss example, even though the controller load is only 37 VA, a standard 40 VA transformer is
not sufficient due to the line loss. From Fig. 44, a 40 VA
transformer is just under 100 percent loaded (for the 37 VA controller) and, therefore, has a secondary voltage of
22.9 volts. (Use the lower edge of the shaded zone in Fig. 44
that represents the worst case conditions.) When the I x R loss of four volts is subtracted, only 18.9 volts reaches the controller, which is not enough voltage for proper operation.
In this situation, the engineer basically has three alternatives:
1. Use a larger transformer; for example, if an 80 VA model is used an output of 24.4 volts minus the four volt
line loss supplies 20.4V to the controller. See Fig. 44.
Although acceptable, the four-volt line-loss in this example is higher than recommended. See the following IMPORTANT.
2. Use heavier gauge wire for the power run. 14 AWG
(2.0 mm
2
) wire has a resistance of 2.57 ohms per 1000 ft. which, using the preceding formula, gives a line-loss of only 1.58 volts (compared with 4.02 volts). This would allow a 40 VA transformer to be used. 14 AWG (2.0 mm
2
) wire is the recommended wire size for 24 Vac wiring.
3. Locate the transformer closer to the controller, thereby reducing the length of the wire run, and the line loss.
74-3079 42
EXCEL 15 W7760C PLANT CONTROLLER
The issue of line-loss is also important in the case of the output wiring connected to the Triac digital outputs. The same formula and method are used. The rule to remember is to keep all power and output wire runs as short as practical.
When necessary, use heavier gauge wire, a bigger transformer, or install the transformer closer to the controller.
IMPORTANT
No installation should be designed where the line loss is greater than two volts to allow for nominal operation if the primary voltage drops to 102 Vac
(120 Vac minus 15 percent).
To meet the National Electrical Manufacturers Association
(NEMA) standards, a transformer must stay within the NEMA
limits. The chart in Fig. 44 shows the required limits at various
loads.
With 100 percent load, the transformer secondary must supply between 23 and 25 volts to meet the NEMA standard.
When a purchased transformer meets the NEMA standard
DC20-1986, the transformer voltage regulating ability can be considered reliable. Compliance with the NEMA standard is voluntary.
21
20
19
18
17
16
15
14
27
26
25
24
23
22
0 50 100
% OF LOAD
150 200
M993
Fig. 44. NEMA class 2 transformer voltage output limits.
The following Honeywell transformers meet this NEMA standard:
Transformer Type
AT20A
AT40A
AT72D
AT87A
AK3310 Assembly
VA Rating
20
40
40
50
100
Step 4. Prepare Wiring Diagrams
Wiring Details
Fig. 45 through 50 show W7760C terminal arrangement and
provide detailed wiring diagrams. Reference these diagrams to prepare site-specific job drawings.
43 74-3079
EXCEL 15 W7760C PLANT CONTROLLER
LINE VOLTAGE
SUPPLY
FAN
DIFFERENTIAL
PRESSURE
SENSOR
24 VAC
CONTACTOR
FAN
STATUS
1
HONEYWELL
W7760C
PLANT
CONTROLLER
CONNECT
POWER TO
TERMINALS
45 AND 47
TRANS-
FORMER
HONEYWELL
W7760C
PLANT
CONTROLLER
ML7984B PWM
VALVE ACTUATOR
T6 T5 C B W R
1
CONNECT
POWER TO
TERMINALS
45 AND 47
TRANS-
FORMER
EARTH
GROUND
EARTH
GROUND
Fig. 45. Typical W7760C wiring diagram.
M14521
M14522
Fig. 46. Typical PWM Valve Actuator to W7760C.
74-3079 44
4 TO
20mA
499 OHM
1%
HONEYWELL
W7760C
PLANT
CONTROLLER
CONNECT
POWER TO
TERMINALS
45 AND 47
TRANS-
FORMER
EXCEL 15 W7760C PLANT CONTROLLER
HONEYWELL
W7760C
PLANT
CONTROLLER
CONNECT
POWER TO
TERMINALS
45 AND 47
TRANS-
FORMER
EARTH
GROUND
EARTH
GROUND
PT3000 OR 20K NTC. 2-WIRE
TEMPERATURE SENSOR
Fig. 47. Typical Analog Inputs to W7760C
M14523
C7600B
HUMIDITY
SENSORS
V+ OUT GND
M14524
Fig. 48. Typical 2 to 10 Volt Humidity Sensor to W7760C
(C7600B is 3 wire device).
45 74-3079
EXCEL 15 W7760C PLANT CONTROLLER
HONEYWELL
W7760C
PLANT
CONTROLLER
HONEYWELL
W7760C
PLANT
CONTROLLER
CONNECT
POWER TO
TERMINALS
45 AND 47
TRANS-
FORMER
CONNECT
POWER TO
TERMINALS
45 AND 47
TRANS-
FORMER
DIGITAL
INPUT
Fig. 49. Typical Digital Input to W7760C.
EARTH
GROUND
M14525
EARTH
GROUND
INPUT GND
RP7517A
ELECTRONIC-PNEUMATIC
TRANSDUCER
M14526
Fig. 50. Typical RP7517A Electronic Pneumatic
Transducer to W7760C.
74-3079 46
EXCEL 15 W7760C PLANT CONTROLLER
General Considerations
NOTE: For field wiring, when two or more wires attach to the
same terminal twist them together per Fig. 39. Devia-
tion from this rule can result in improper electrical contact.
Table 21 lists wiring types, sizes, and distances for Excel 15
products. The terminals on the W7760C, W7751, W7750,
W7753, W7761, and T7770 accept 14 through 22 AWG (2.0 to 0.34 mm
2
) wire. The T7300F/Q7300H Commercial
Thermostat/Communicating Subbase accept 18 through
22 AWG (1.0 to 0.34 mm
2
) wire.
Table 21. Field Wiring Reference Table (Honeywell listed as AK#### or equivalent).
Wire
Function
L
ON
W
ORKS
Bus
(Plenum)
L
ON
W
ORKS
Bus (Non-
Plenum)
Input
Wiring
Sensors
Contacts
Output
Wiring
Actuators
Relays
Recommended
Minimum Wire
Size AWG (mm
22 AWG
(0.34 mm
2
)
22 AWG
(0.34 mm
2
)
18 to 22 AWG
(1.0 to 0.34 mm
2
)
2
) Construction
Twisted pair solid conductor, nonshielded or Echelon approved cable.
Twisted pair solid conductor, nonshielded or Echelon approved cable.
Multiconductor (usually five-wire cable bundle).
For runs >200 ft. (61m) in noisy EMI areas, use shielded cable.
14 AWG (2.0 mm
2
)
18 AWG (1.0 mm
2
) acceptable for short runs)
Any pair nonshielded
(use heavier wire for longer runs).
Power
Wiring
14 AWG (2.0 mm 2 ) Any pair nonshielded
(use heavier wire for longer runs).
Specification or
Requirement
Level IV
140°F (60°C) rating
Level IV
140°F (60°C) rating
NEC Class 2
140°F (60°C) rating
Vendor Wire Type
Honeywell
AK3791 (one twisted pair)
AK3792 (two twisted pairs)
Honeywell
AK3781 (one twisted pair)
AK3782 (two twisted pairs)
Honeywell
AK3754 (14 AWG) twisted pair AK3909 (14 AWG) single conductor
Maximum Length ft.
(m)
Refer to L
ON
W
ORKS
Bus
Wiring Guidelines for maximum length
Refer to L
ON
W
ORKS
Limited by line-loss effects on power consumption. (See Line
Loss subsection.)
Bus
Wiring Guidelines for maximum length
140°F (60°C) rating
Standard thermostat wire 1000 ft. (305m) for 18
AWG 200 ft. (61m) for 22
AWG
NEC Class 2
140°F (60°C) rating
Honeywell
AK3702 (18 AWG)
AK3712 (16 AWG)
AK3754 (14 AWG)
Limited by line-loss effects on power consumption. (See Line
Loss subsection.)
Step 5. Order Equipment
After compiling a bill of materials through completion of the
previous application steps, refer to Table 22 for ordering
information. Contact Honeywell for information about
Controllers and Wall Modules with no logo.
Part Number
W7760C2009
W7750A2005
W7750B2011
W7750C2001
W7751B2002
W7751D2008
W7751F2003
W7751H2009
Table 22. Excel 15 W7760C Ordering Information.
Product Description
Excel 15 W7760C Plant Controller
Excel 10 W7750 Controllers:
Constant Volume AHU Controller (W7750A)
Comments
Excel 15 Controller
Constant Volume AHU Controller (W7750B)
Constant Volume AHU Controller (W7750C)
Three Analog Inputs, Three Digital Inputs and
Six 24 Vac Relay Outputs
Six Analog Inputs, Five Digital Inputs and Eight
(High-side Low-side switchable)Triac Outputs
Six Analog Inputs, Five Digital Inputs, Five Triac
Outputs and Three Analog Outputs
Excel 10 W7751 Controllers:
OEM Base Board (Only in bulk pack of 10)
Base Board, Mounting Enclosure
Base Board, Mounting Enclosure
Smart VAV II Actuator is a factory-combined
VAV Box Controller and a ML6161B1000
Actuator
Order 207912 Snaptrack (See Accessories)
With External Wiring
With External Wiring
Plenum Rated
47 74-3079
W7761A2002
T7770C1044
T7770C1010
T7770C1028
T7770C1051
T7770C1036
T7770D1000
T7770D1018
T7560A1018
T7770A1006
T7770A1014
T7770A2004
T7770A2012
T7770B1004
T7770B1046
T7770B1012
T7770B1020
T7770B1053
T7770B1038
T7770C1002
EXCEL 15 W7760C PLANT CONTROLLER
Part Number
Y7751D2006
Y7751F2001
206166A
206167A
206168B
W7753A2002
Table 22. Excel 15 W7760C Ordering Information. (Continued)
Product Description
W7751D2008 Base Board, Mounting
Enclosure packed with ML6161B1000 Actuator
Comments
With External Wiring
W7751F2003 Base Board, Mounting Enclosure packed with ML6161B1000 Actuator
With External Wiring
W7751D,F Subbases and Electronics Assy.
Subbase for W7751D with Internal Wiring
Subbase for W7751F with External Wiring
Available in bulk pack of 10 each (for use with
206168B VAV Controller Assembly).
Available in bulk pack of 10 each (for use with
206168B VAV Controller Assembly).
Cover and Electronics for W7751D,F Contains Circuit Board for use with 206166A or
206167A Subbases (available only in bulk pack of 10).
Excel 10 W7753A Controller
Unit Ventilator Controller (W7753A) Six Analog Inputs, Five Digital Inputs and Eight
Triac Outputs
Excel 10 W7761A
Remote Input/Output Device RIO
T7770 or T7560 Wall Modules for Excel 10s:
Sensor with Honeywell Logo
Sensor with No Logo
Used with Excel 10 Controllers
Used with Excel 10 Controllers
Sensor, L
ON
W
ORKS
Jack and Honeywell Logo Used with Excel 10 Controllers
Used with Excel 10 Controllers
Degrees F Absolute
Sensor with L
ON
W
ORKS
Jack and No Logo
Sensor with Setpoint and L
ON
W
ORKS
Jack,
Honeywell Logo
Sensor with Setpoint and L
ON
W
ORKS
Jack,
Honeywell Logo
Sensor with Setpoint and L
ON
W
ORKS
Jack, No
Logo
Relative Setpoint
Degrees F Absolute
Degrees C Absolute Sensor with Setpoint and L
ON
W
ORKS
Jack,
Honeywell Logo
Sensor with Setpoint and L
ON
W
ORKS
Jack, No
Logo
Sensor with Setpoint and L
ON
W
ORKS
Jack, No
Logo
Sensor with Setpoint, Bypass/LED and
L
ON
W
ORKS
Jack, Honeywell Logo
Sensor with Setpoint, Bypass/LED and
L
ON
W
ORKS
Jack, Honeywell Logo
Sensor with Setpoint, Bypass/LED and
L
ON
W
ORKS
Jack, No Logo
Sensor with Setpoint, Bypass/LED and
L
ON
W
ORKS
Jack, Honeywell Logo
Sensor with Setpoint, Bypass/LED and
L
ON
W
ORKS
Jack, No Logo
Relative Setpoint
Degrees C Absolute
Degrees F Absolute
Relative Setpoint
Degrees F Absolute
Degrees C Absolute
Relative Setpoint
Sensor with Setpoint, Bypass/LED and
L
ON
W
ORKS
Jack, No Logo
Sensor with Bypass/LED and L
ON
W
ORKS
Jack,
Honeywell Logo
Sensor with Bypass/LED and L
ON
W
ORKS
Jack,
No Logo
Digital Wall Module with Sensor, Setpoint and
Bypass/LCD, Honeywell Logo
Degrees C Absolute
Degrees F Absolute
Degrees C Absolute
74-3079 48
EXCEL 15 W7760C PLANT CONTROLLER
Table 22. Excel 15 W7760C Ordering Information. (Continued)
Part Number
T7560A1016
C7770A1006
C7031J1050
C7031B1033
C7031C1031
C7031D1062
C7031F1018
C7031K1017
C7100A1015
C7170A1002
Q7760A2001
Q7752A2009
Q7740A1008
Q7740B1006
Digital Wall Module with Sensor, Setpoint,
Bypass/LCD and Humidity, Honeywell Logo
Sensors:
Product Description
Air Temperature Sensor. 20 Kohm NTC nonlinearized
Averaging Discharge/Return Air Temperature
Sensor. 20 Kohm NTC
Comments
Duct-mounted sensor that functions as a primary and/or secondary sensor.
Duct element cord length 12 ft. (3.7m).
Discharge Air or Hot Water Temperature
Sensor. 20 Kohm NTC
Use 112622AA Immersion Well.
Duct Discharge/Return Air Sensor. 20 Kohm 18 in. (457mm) insertion length.
Hot or chilled Water Temperature Sensor. 20
Kohm NTC
—
W7750B,C only Outside Air Temperature Sensor. 20 Kohm
NTC
Hot or chilled Water Temperature Sensor. 20
Kohm NTC
Strap-on
13 in. (330mm) insertion length.
Averaging Discharge/Return Air Temperature
Sensor. PT3000
Outdoor Air Temperature Sensor. PT3000
Echelon Based Components and Parts:
—
Serial Interface
Serial Interface (PCMCIA card)
Excel 10 2-Way Repeater
Excel 10 4-Way Repeater
(FTT)
(FTT)
Used to extend the length of the L
ON
W
ORKS
Bus. Contains built in termination modules.
Used to extend the length of the L
ON
W
ORKS
Bus. Contains built in termination modules.
Termination Module One/two required per L
ON
W
ORKS
Bus segment
Operator Terminal Cable for L
ON
W
ORKS
Bus Serial interface to wall module or controller
209541B
205979
EL7680A1008
Accessories (Sensors):
Wall Mounted Wide View Infrared Occupancy
Sensor
EL7628A1007 Ceiling Mounted Infrared Occupancy Sensor
EL7611A1003, EL7612A1001 Ultrasonic Occupancy Sensors
EL7630A1003,
EL7621A1002,
EL7621A1010
C7242A1006
Power Supply/Control Units for Occupancy sensors
CO
2
Sensor/Monitor
—
—
—
—
Use to measure the levels of carbon dioxide
C7400A1004
C7600B1000
C7600C1008
C7600C1018
Solid State Enthalpy Sensor (4 to 20 mA)
Solid State Humidity Sensor (2 to 10 V)
Solid State Humidity Sensor (4 to 20 mA)
Solid State Humidity Sensor (2 to 10 V)
For outdoor and return air enthalpy
For outdoor and return air humidity
For outdoor and return air humidity
For outdoor and return air humidity
Accessories:
MMC325-010, MMC325-020 Pneumatic Retrofit Transducers. Select pressure range: (010) 0 to 10 psi (68.97 kPa) or
(020) 0 to 20 psi (137.93 kPa).
Use to control Pneumatic reheat valves.
MMCA530
MMCA540
ML7984B3000
ML6161B1000
M6410A
DIN rail adapter for MMC325 Transducers
Metal enclosure for MMC325 Transducers
—
—
Valve Actuator Pulse Width Modulation (PWM) Use with V5011 or V5013 F and G Valves
Damper Actuator Series 60 —
Valve Actuator Series 60 Use with V5852/V5853/V5862/V5863 Valves
49 74-3079
EXCEL 15 W7760C PLANT CONTROLLER
Table 22. Excel 15 W7760C Ordering Information. (Continued)
Part Number
ML684A1025
ML6464A1009
ML6474A1008
ML6185A1000
V5852A/V5862A
Product Description
Versadrive Valve Actuator with linkage, Series
60
Comments
Use with V5011 and V5013 Valves
Direct Coupled Actuator, 66 lb-in. torque,
Series 60
Direct Coupled Actuator, 132 lb-in. torque,
Series 60
Direct Coupled Actuator, 50 lb-in. spring return Series 60
Two-way terminal unit water valve; 0.19, 0.29,
0.47, 0.74, 1.2, and 1.9 C or 2.9 and 4.9 C v v
1/2 in. npt (13 mm)
3/4 in. npt (19 mm)
—
—
Use with M6410 Valve Actuator. Close-off rating for 0.19 to 1.9 C v
is 65 psi; for 2.9 and 4.9, C v
is
45 psi. (Coefficient of volume or capacity index
C v
= gallons per minute divided by the square root of the pressure drop across the valve.)
V5853A/V5863A
R8242A
Three-way mixing terminal unit hot water valve;
0.19, 0.29, 0.47, 0.74, 1.2, and 1.9 C npt (13 mm) or 2.9 and 4.9 C v mm) v
1/2 in.
3/4 in. npt (19
Contactor, 24 Vac coil, DPDT
AT72D, AT88A, AK3310, etc. Transformers
Use with M6410 Valve Actuator. Close-off rating for 0.19 to 0.74 C psi; 2.9 and 4.9 C v
is 55 psi; 1.2 and 1.9 C v
is 26 psi.
v
is 22
—
—
EN 50 022
207912
—
Fair-Rite
229997CB
044316451 or equivalent Honeywell part
—
DIN rail 35 mm by 7.5 mm (1-3/8 in. by 5/16 in.) Obtain locally: Each controller requires 5 in.
Two DIN rail adapters Obtain locally: Part number TKAD, from Thomas and Betts, two for each controller.
(pack of 10) Snaptrack, 3.25 in. (82 mm) by 9 in. (228 mm) for use with W7751B Controller
Split ferrite cores Split ferrite cores must also be in a metal enclosure when used with W7751B VAV
Controller.
—
5-micron Air Filters for Microbridge Sensor.
Cabling:
Serial Interface Cable, male DB-9 to female
DB-9 or female DB-25.
Honeywell AK3712 (typical or equivalent)
16 AWG (1.3 mm
2
) twisted pair
Honeywell AK3754 (typical or equivalent)
14 AWG (2.0 mm
2
) two conductor
Obtain locally from any computer hardware vendor.
Level IV 140°F (60°C) rating Honeywell
AK3791 (one twisted pair)
AK3792 (two twisted pairs)
Honeywell AK3781 (one twisted pair) AK3782 (two twisted pairs)
Honeywell AK3725
L
ON
W
ORKS
Bus (plenum): 22 AWG (0.34 mm 2 ) twisted pair solid conductor, nonshielded or
Echelon approved cable.
L
ON
W
ORKS
Bus (nonplenum): 22 AWG (0.34 mm 2 ) twisted pair solid conductor, nonshielded or Echelon approved cable.
Inputs: 18 AWG (1.0 mm
2
) five wire cable bundle
Level IV 140°F (60°C) rating
Standard thermostat wire
Honeywell AK3752 (typical or equivalent)
Outputs/Power: 14 to 18 AWG (2.0 to 1.0 mm
2
) NEC Class 2 140°F (60°C) rating
Honeywell AK3702 (typical or equivalent)
18 AWG (1.0 mm
2
) twisted pair
Non-plenum
Non-plenum
Non-plenum
Step 6. Configure Controllers
L
ON
S
PEC
software is used to configure W7760C Controllers to match their intended application. The L
ON
S
PEC
ZL7760A has
Help that provides details for operating the PC software.
74-3079 50
EXCEL 15 W7760C PLANT CONTROLLER
Step 7. Troubleshooting
Check Installation and Wiring:
Inspect all wiring connections at the W7760C terminals, and verify compliance with job drawings. If any wiring changes are required, first be sure to remove power from the device before starting work. Pay particular attention to:
— 24 Vac power connections. Verify that multiple devices powered by the same transformer are wired with the transformer secondary connected to the same input
terminal numbers on each W7760C. See Fig. 43.
Controller configurations are not necessarily limited to two devices, but the total power draw including accessories cannot exceed 100 VA when powered by the same transformer (U.S. only).
— Device wiring. Be sure that each device is wired (terminal
49) on the W7760C to a verified earth ground using a wire run as short as possible with the heaviest gauge wire available, up to 14 AWG (2.0 mm
2
) with a minimum of
) for each controller in the group. See 18 AWG (1.0 mm
2
— Verify Triac wiring to external devices uses the proper load power/24 Vac hot terminals (terminals 31 through 42 on the
W7760C). Check for 24 Vac with a meter.
L
ON
W
ORKS
NETWORK JACK
STATUS LED
SERVICE
PIN
PUSH
BUTTON
M18060A
Fig. 51. LED location on W7760C.
NOTE: All wiring must comply with applicable electrical codes and ordinances or as specified on installation wiring diagrams.
VERIFY TERMINATION MODULE PLACEMENT
The installation wiring diagrams should indicate the locations for placement of 209541B Termination Module(s). Refer to the
L
ON
W
ORKS
Bus Wiring Guidelines form, 74-2865, and the
Excel 10 FTT Termination Module Installation Instructions form, 95-7554. Correct placement of the termination module(s) is required for proper L
ON
W
ORKS
Bus operation.
Startup
W7760C Controller Status LED
The LED on the front and center of a W7760C Controller provides a visual indication of the status of the device. See
Fig. 51. When the W7760C receives power, the LED should
appear in one of the following allowable states:
1. Off - no power to the processor.
2. Continuous On - processor is in initialized state.
3. Slow Blink - controlling, normal state.
4. Fast Blink - when the W7760C has an alarm condition.
Troubleshooting Excel 10 Controllers and Wall Modules:
In addition to the following information, refer to the Installation
Instructions and Checkout and Test manual for each product.
See the Applicable Literature section for form numbers.
Alarms
When an Excel 15 W7760C has an alarm condition, it reports it to the central node on the L
ON
W
ORKS
Bus (typically, a
W7760A). See Table 23. Information contained in an alarm
message is:
• Subnet Number:
L
ON
W
ORKS
Bus segment that contains the node that has the alarm condition.
• Node Number:
Node that has the alarm condition (see Network Alarm).
• Alarm Type:
Specific alarm being issued. An Excel 15C can provide the
Table 23. Excel W7760C Enumerated Alarms.
W7760C Alarm
RETURN_TO_NORMAL
Alarm Definition
Returns to normal after being in an alarm condition. The sum of this alarm code and another alarm code indicates that the alarm condition has returned to normal.
No alarms are currently being detected.
NO_ALARM
SET_POINT_LOOP1_ALARM Setpoint loop alarms occur when the control sensor exceeds the configured high or low delta for the pre delay time. These alarms are reset when the control sensor value goes back inside of the deltas for the post delay time.
SET_POINT_LOOP2_ALARM See the meaning for SET_POINT_LOOP1_ALARM type.
SET_POINT_LOOP3_ALARM See the meaning for SET_POINT_LOOP1_ALARM type.
SET_POINT_LOOP4_ALARM See the meaning for SET_POINT_LOOP1_ALARM type.
SET_POINT_LOOP5_ALARM See the meaning for SET_POINT_LOOP1_ALARM type.
51 74-3079
EXCEL 15 W7760C PLANT CONTROLLER
Table 23. Excel W7760C Enumerated Alarms.
W7760C Alarm Alarm Definition
SET_POINT_LOOP6_ALARM See the meaning for SET_POINT_LOOP1_ALARM type.
SET_POINT_LOOP7_ALARM See the meaning for SET_POINT_LOOP1_ALARM type.
SET_POINT_LOOP8_ALARM See the meaning for SET_POINT_LOOP1_ALARM type.
SET_POINT_LOOP9_ALARM See the meaning for SET_POINT_LOOP1_ALARM type.
SET_POINT_LOOP10_ALARM See the meaning for SET_POINT_LOOP1_ALARM type.
INPUT_NV_ALARM One or more network variable (NV) inputs have failed in receiving an update within their specified FAILURE_DETECT_TIME. This is valid only on those NVs with fail detect.
SENSOR_ALARM This indicates an open or short on an Analog Input or a problem with one of the calibration channels.
FLASH_CHECKSUM_ALARM The FLASH checksum alarm indicates at least one of the configuration (internal to controller) sections or the NV configuration table has a bad checksum and needs a download. The
W7760C reinitializes all of the sections and the NV configuration table in FLASH to the default values. These make the W7760C unconfigured. This alarm goes away on the next powerup/ reset. The W7760C never issues a Return to Normal because a download of all files causes a reset and erases any RTN that could have been issued on a download. This alarm should never occur on a properly working W7760C. Controller lost configuration and needs download.
INPUT_REM_POLL_ALARM The input remote poll alarm is set when the W7760C has not been able to get a new value for a general poll point for 300 seconds.
FILE_ALARM When received as a file window out of sequence, window didn’t complete or received more
bytes than were supposed to. Controller lost configuration and needs download. Redownload
the file and reset the W7760C to make the error/alarm go away.
RAM_CHECKSUM_ALARM
ALARM_NOTIFY_DISABLE
This alarm and its return to normal tells the user the W7760C had a problem and fixed it.
Alarms have been disabled.
NOTE: The node can be reset by switching the node to
MANUAL and then to the normal operating mode.
Current alarm history is available through L
ON
S
PEC
Reports function.
Assigning Neuron
®
ID
Assigning an Neuron ID allows a device on the L
ON
W
ORKS
Bus to be positively identified. The controller Neuron ID number can be used to confirm the physical location of a particular Excel 15, Excel 10, and T7300F/Q7300H. See
Table 23 for information contained in an alarm message.
There are two methods of assigning a Neuron ID from an
Excel 15 W7760C Controller. One uses a hardware service pin button on the side of the controller and manually entering the Neuron ID is the second.
When an Assign ID command (use the service pin button is issued from L
ON
S
PEC
, the node goes into the
SERVICE_MESSAGE mode for five minutes. In the
SERVICE_MESSAGE mode, pressing the hardware service pin button on the bottom of the controller causes the Service
Message to be broadcast on the network. See Fig. 51. All
other functions are normal in the SERVICE_MESSAGE mode. When manually entering the Neuron ID and issuing the
Assign ID command, LonSpec locates and communicates directly with the controller (the controller does not go into the
SERVICE_MESSAGE mode in this case). Refer to the
L
ON
S
PEC
ZL7760A software Help for more information on the
ID assignment process.
Home and Building Control Home and Building Control
Honeywell Honeywell Limited-Honeywell Limitée
1985 Douglas Drive North 35 Dynamic Drive
Golden Valley, MN 55422 Scarborough, Ontario
M1V 4Z9
74-3079 J.H. 9-00
Printed in U.S.A. on recycled paper containing at least 10% post-consumer paper fibers.
www.honeywell.com
advertisement
Key Features
- LONWORKS network communication
- HVAC equipment control
- Remote control
- Analog and digital I/O
- Configurable control loops