Installation Guide Bacharach HGM-MZ to Johnson Metasys N2 Communications Adapter

Installation Guide  Bacharach HGM-MZ to Johnson Metasys N2 Communications Adapter
3015‐5514 Revision 0 9/13/10 Installation Guide
Bacharach HGM-MZ to Johnson Metasys N2
Communications Adapter
Electrically Isolated N2 Port Version
Introduction
The Bacharach HGM-MZ to Johnson Metasys N2 Communications Adapter enables an HGM-MZ
Refrigerant Monitor to communicate with a Metasys building management system. Zone PPM readings,
flow status, refrigerant selections, and HGM internal health may be viewed on Metasys operator
stations. In addition, each HGM zone supports three levels of alarming (Leak, Spill, Evacuate) through
Metasys and each alarm threshold can be set through Metasys.
The N2 Communications Adapter can be used in conjunction with the MZ-RD remote display if desired.
Wiring details and operational limitations when using the MZ-RD will be discussed below.
Caution
The adapter is powered from the 120/240V Universal Power Supply connection on the HGM main
board. 120/240V is present on the lower left corner of this adapter within the area shown on the board
silkscreen. Keep fingers away from this area when HGM is powered.
Adapter Installation Inside HGM-MZ
The communications adapter board will normally be installed in the HGM-MZ at the factory. It can,
however, be field installed by following the instructions below:
The following installation materials are needed for field installation of the adapter:
(5) 6-32 x ¼” screws (standard finish)
The adapter board mounts on the rear of the HGM-MZ enclosure door. Position the adapter board over
the five standoffs on the door and install with 6-32 fasteners through the board and into the standoffs.
Connect power wiring from the HGM-MZ’s 120/240V Universal Power Supply terminal block to the
adapter board’s POWER terminal block. Use UL approved wire. Wire polarity does not matter.
Page 1 of 9 3015‐5514 Revision 0 9/13/10 If an MZ-RD remote display is NOT used with the adapter, refer to Figure 1 for wiring details. In this
case, all wiring between the HGM-MZ and the only external cable is the N2 communications cable.
Figure 1 – Wiring w/o Remote Display
Page 2 of 9 3015‐5514 Revision 0 9/13/10 If an MZ-RD remote display IS to be used with the adapter, refer to Figure 2 for wiring details. Note
that when the MZ-RD is used, TWO RS-485 cables must be run between the HGM-MZ and MZ-RD, so
plan accordingly.
In either case, be sure to set the HGM-MZ’s internal “Terminator” slide switch next to the RS-485
terminal block to the “In” position.
Figure 2 – HGM-MZ to N2 Communications Adapter: Wiring w/Remote Display
Page 3 of 9 3015‐5514 Revision 0 9/13/10 Field Hookup of N2 Communications
The “BAS BUS” (N2) RS-485 communications port on the adapter is electrically isolated from the
HGM-MZ and from earth ground. This prevents problems with potential differences in “ground”
between physically separate locations.
Connect the N2 ‘+’ wire to the BAS BUS N+ terminal block screw. Connect the N2 ‘-‘ wire to the BAS
BUS N- terminal block screw. Connect the N2 REF wire to the BAS BUS REF terminal block screw.
Shield connection practices vary. Refer to Johnson Controls Metasys N2 documents for Johnsonrecommended practices. Options are to hard-terminate the shield to the case, soft-terminate (through a
small-value capacitor) the shield to the case, or leave the shield floating.
If the adapter is the last device on the N2 line, the RS-485 TERM jumper just below the BAS BUS
terminal block should be installed. Otherwise leave the RS-485 TERM jumper disconnected.
Setting HGM Communication Address On Adapter
See Figure 3 for the location of adapter dipswitches A and B.
Switches 5-8 on the adapter’s ‘A’ dipswitch are used to match the node address set on the HGM’s
address dipswitch (on HGM main board). Values from 0-15 are possible:
HGM Address
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
A5
Off
Off
Off
Off
Off
Off
Off
Off
On
On
On
On
On
On
On
On
A6
Off
Off
Off
Off
On
On
On
On
Off
Off
Off
Off
On
On
On
On
A7
Off
Off
On
On
Off
Off
On
On
Off
Off
On
On
Off
Off
On
On
A8
Off
On
Off
On
Off
On
Off
On
Off
On
Off
On
Off
On
Off
On
Since the HGM is the only node on the adapter-to-HGM interface, address 1 is normally used. Be sure
to set the same address on the adapter and the HGM main board dipswitches.
Page 4 of 9 3015‐5514 Revision 0 9/13/10 Figure 3 – HGM-MZ to Metasys N2 Adapter: Dipswitches and LED Indicators
Page 5 of 9 3015‐5514 Revision 0 9/13/10 Setting Metasys N2 Address On Communication Adapter
Switches 1-8 on the adapter’s ‘B’ dipswitch are used to set the Metasys N2 node address. Possible
addresses are 1-255. Use the following technique to set switches B1-B8:
Divide the desired N2 address by 16. Take the integer part of the result (0-15) and use the following
table to set switches B1-B4:
N2 address upper half
(N2 address lower half)
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
B1
(B5)
Off
Off
Off
Off
Off
Off
Off
Off
On
On
On
On
On
On
On
On
B2
(B6)
Off
Off
Off
Off
On
On
On
On
Off
Off
Off
Off
On
On
On
On
B3
(B7)
Off
Off
On
On
Off
Off
On
On
Off
Off
On
On
Off
Off
On
On
B4
(B8)
Off
On
Off
On
Off
On
Off
On
Off
On
Off
On
Off
On
Off
On
Take the value 0-15 from above and multiply that times 16. Subtract the result from the desired N2
address. This gives another number 0-15. Use this number and the table to set switches B5-B8.
Example: Desired N2 address is 35.
35 divided by 16 gives 2.1875.
Integer part of answer is 2.
Use table entry for ‘2’ to set B1=Off, B2=Off, B3=On, B4=Off.
Multiply 2 (from above) times 16 = 32.
Subtract 32 from desired address: 35-32=3.
Use table entry for ‘3’ to set B5=Off, B6=Off, B7=On, B8=On.
Page 6 of 9 3015‐5514 Revision 0 9/13/10 Configuring the HGM-MZ with MZ-RD or Laptop PC
The only HGM parameters that are changeable through Metasys are the alarm thresholds. Configuring
the HGM for refrigerant type and length of tubing for each zone (zero length to disable a zone) must be
done with the MZ-RD remote display or a laptop PC. Refer to the appropriate Bacharach instructions
for configuring these items. HGM’s are commonly custom-configured at the factory per the customer’s
needs, so field configuring these parameters may not be necessary.
If configuring the HGM-MZ with an MZ-RD, the communications adapter’s presence will not affect the
standard configuration procedure. If configuring with a laptop PC, temporarily disconnect the HGMMZs RS-485 cable from the adapter until configuration is complete and the laptop is disconnected.
Setting up the Metasys Database
The Metasys Point Map included with this document will provide the information needed to set up AI
(analog input), BI (binary input), and ADI (internal integer) points in the Metasys database. Additional
comments are provided below to supplement the map. The HGM-MZ can support up to 16 zones in
groups of 4 zones, but a particular HGM-MZ may not have all zones installed. It is not necessary to
include points in the Metasys database for zones that are not installed in the HGM-MZ.
Each monitored zone in the HGM supports three levels of alarming: Leak, Spill, Evacuate. Since the
Metasys N2 architecture does not support three different levels of high alarming per AI point, each
HGM zone is set up as THREE AI points. The first AI point for a zone supports a Leak Alarm, the
second AI point for a zone supports a Spill Alarm, and the third AI point for a zone supports an
Evacuate Alarm. All three AI points for a zone return the same PPM reading, it’s the alarm thresholds
that differ.
Alarm thresholds in PPM are set through Metasys by setting each AI point’s “High Alarm Limit.” Each
alarm threshold may be set to a value of 1-65535 PPM. Please note that for a particular zone, the Spill
threshold must be set higher than the Leak threshold, and the Evacuate threshold must be set higher than
the Spill threshold. All Metasys warning/alarm limits other than “High Alarm Limit” are ignored.
Because the HGM samples slowly, alarm “differential” to prevent alarm chattering is not needed.
Therefore the Metasys “Differential” parameter for each AI may be written but will be ignored.
Certain HGM faults will cause various points to be marked unavailable/unreliable. For example, a
global flow fault will cause ALL AI PPM values to be marked unreliable, whereas a flow fault on a
single zone will only cause the three AI PPM values associated with that zone to be marked unreliable.
Note that any time power is cycled to the HGM, it goes through a 15-minute warm-up cycle (even if it
was already warm!). During this time, all AI PPM values will be marked unreliable. Don’t cycle HGM
power needlessly if you would like to get valid PPM readings with the next 15 minutes!
There are several ADI points which can provide useful information such as type of refrigerant
programmed for each zone, number of zones actually installed in the HGM, the number of zones in
alarm, HGM operating mode, etc.
Page 7 of 9 3015‐5514 Revision 0 9/13/10 Alarm Acknowledge Options
Two alarm acknowledge options are supported – Auto Acknowledge and Manual Acknowledge.
In the Auto Acknowledge mode, the HGM-MZ will clear its alarm outputs the next time the alarmed
zone is sampled and its PPM has dropped below the alarm thresholds. No intervention from the Metasys
network is necessary.
In the Manual Acknowledge mode, the HGM-MZ will never clear its alarm outputs until the Metasys
network connection has acknowledged the Change-of-State alarms reported to Metasys. Once Metasys
has acknowledged the alarm messages, the HGM will clear its alarm outputs the next time the alarmed
zone is sampled and its PPM has dropped below the alarm thresholds. Please note that the Metasys
acknowledgement is a field-level acknowledgement that takes place automatically (typically within a
few seconds). It is not a human operator acknowledging that the alarm was seen on a console. The
Metasys acknowledgement does, however, mean that the system has caught the alarm and that it will be
reported to some higher level.
Dipswitch A1 on the adapter selects which alarm acknowledge option is used:
A1 On = Auto Acknowledge
A1 Off = Manual Acknowledge
Operating Limitations When Using MZ-RD Remote Display
When an MZ-RD remote display is used, the N2 network will have access to the HGM-MZ as long as
the MZ-RD is in either the SYSTEM or ZONE VIEW screen. If the MZ-RD is set to display any other
screen, it will respond to polls from the N2 adapter with an HGM BUSY exception code. The N2
adapter will handle the exception by marking most points as Unavailable and setting the Unavailable
Reason point = HGM Busy. When the MZ-RD is returned to the SYSTEM or ZONE VIEW screen,
normal N2 monitoring will resume.
If the operator leaves the MZ-RD in some screen other than SYSTEM or ZONE VIEW for an extended
period of time (10 minutes default), the MZ-RD times out and automatically returns to either the
SYSTEM or ZONE VIEW screen. This will restore normal N2 monitoring.
Page 8 of 9 3015‐5514 Revision 0 9/13/10 Communications LED Indicators
See Figure 3 for the locations of the communications LED indicators.
The communications adapter board has four LED communications status indicators numbered 1-4. The
meanings of these indicators are as follows:
LED 1 ON: Adapter is transmitting a poll/command to the HGM
LED 2 ON: Adapter is receiving a response from the HGM
LED 3 ON: Adapter is transmitting a response to Metasys N2
(Because poll/command was directed to this slave)
LED 4 ON: Adapter is receiving a poll/command from Metasys N2
(directed to ANY N2 slave, not necessarily this one)
Under normal conditions, you would expect to see a lot of activity on LED 4 since the N2 master is
continually polling all N2 slaves on the line. LED 3 will show activity based on how often the N2
master is polling the adapter (versus other N2 slaves on the line). If there are few N2 slaves on the line,
a lot of polls will be directed to the adapter and LED 3 will blink frequently and LED 3 will blink less
frequently.
LED 1 and LED 2 will only show occasional activity. Since the refrigerant monitoring process is fairly
slow and new data is only available every 15 seconds or so, the adapter polls the HGM at a slow rate to
reduce the communications burden on the HGM main processor.
Miscellaneous Notes
RS-485 communications wires ARE polarity sensitive. If the adapter does not communicate on the N2
RS-485 port, try swapping the communications wires on the N+ and N- terminal block screws. The
HGM port uses the same labels as the HGM main board, so if you match the wires to the labels, polarity
should not be an issue there.
If the adapter seems to not be functioning correctly, it can be restarted without restarting the HGM
simply by pressing the CPU RST button just below the “A” dipswitch. If you restart the adapter by
cycling the HGM’s power, you will have to wait for the HGM’s 15-minute warm-up cycle to end before
PPM readings are available! If restarting the adapter alone doesn’t help, try cycling power to the entire
HGM.
When the adapter software first starts, it attempts to establish communications with the HGM before
attempting to communicate on the N2 port. Do not be concerned after cycling power or pressing CPU
RST that no N2 activity is shown on the LEDs immediately. The software delays about 20 seconds after
a restart before attempting to establish N2 communications.
The LEDs are driven by adapter software states, not by the RS-485 hardware. If an RS-485 connection
stops working in the middle of receiving a message, the RX LED may stay on indefinitely until the
connection starts working again.
Page 9 of 9 
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement