Carrier Fireye PMSTR-4000 User manual

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PMSTR-4000
Quick Start Tips
September 15, 2021
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The PMSTR-4000 Plant Master controls up to eight NXF4000 and/or PPC4000 in any
combination using a central sensor. The connection from the PMSTR-4000 is via
Modbus and uses the dedicated sequencing bus.
WIRING
The Modbus terminals for the sequencing bus are on connector P12:
P12.3: Modbus A+
P12.4: Modbus B-
Just as when using peer-to-peer sequencing, all the connected units must be wired in a
serial string, also known as a “daisy-chain”. This means that each control is connected
to the next, and only the first or the last control is connected to the PMSTR-4000.
CONFIGURATION OF UNITS
First, sequencing must be enabled on each NXF4000 or PPC4000. It is also important
that no control is specified to be the master, and that the LEAD LAG key on the keypad
is disabled so that a master isn’t inadvertently specified in the future. If a master does
get enabled on one of the units there will be communication issues from the PMSTR-
4000.
The sequencing bus has communication settings fixed at 19200 baud, eight data bits,
no parity and one stop bit. The node address for the sequencing bus is the same as the
node address used for the BMS Modbus port.
Settings to change on each NXF4000 or PPC4000:
COMMUNICATION SETUP  UNIT ADDRESS  (1-8)
SEQUENCING SETUP  MASTER SLCT  COMMS
SEQUENCING SETUP  SLAVES AVAILABLE  0
KEYPAD SETUP  LEAD LAG KEY  UNUSED

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PMSTR-4000
Quick Start Tips
September 15, 2021
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CONFIGURATION OF PMSTR-4000
Option parameters are used to configure the PMSTR-4000. To access the option
parameters, press the gear icon. Enter 903 when prompted for a passcode.
The recommended first step when configuring a new installation is to apply the
default settings by setting option 12.0 to 1. This will apply the default settings and
then reset to 0 when complete.
Next, refer to bulletin PMSTR-4001 and go through the option parameters group by
group. This is important so that the sensor can be set up correctly, as well as any other
options such as pump control or outside air reset. The bulletin has a more complete
description of more advanced option groups such as rotation order and unit skipping.
ONLINE STATUS OF UNITS
Once the units are wired and powered, if communication is okay the firing rate should
appear if the unit is running, even if it shows as OFFLINE. Several conditions must be
true before a unit can be recognized as ONLINE (STANDBY, STARTING or
RUNNING):
Communication must be active
Sequencing must be properly enabled on the unit (described earlier)
Virtual HAND-OFF-AUTO switch must be set for AUTO
Unit must not be locked out
Unit must have operating limit input satisfied (voltage on terminal P15.4)
Unit must have burner control input on (from keypad or digital input)
If the unit is running when placed in AUTO, this ensures that all the conditions are met,
and the unit should be assigned a role as lead or lag and should then be controlled by
the PMSTR-4000 immediately.
If a unit is operated in HAND mode, it will show as OFFLINE, but the actual firing rate
will be displayed. This is because the unit is only OFFLINE relative to the PMSTR-4000.
This simply means that the PMSTR-4000 can’t remotely command the unit to help
satisfy the load.
If the unit is running and the firing rate is not being displayed, it is possible that the
Modbus communication is not set up at the units properly or that there is a wiring issue.

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PMSTR-4000
Quick Start Tips
September 15, 2021
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USING MODBUS MONITOR TO VERIFY COMMUNICATION STATUS
A Modbus monitoring program such as ModScan or Shortbus Modbus Scanner can be
used to check if communication is active. Connect the Ethernet port of the PMSTR-4000
to a PC and set up a static IP address to match that of the PMSTR-4000. By default, the
IP address of the PMSTR-4000 is 192.168.0.11, but this can be immediately changed
from option groups 13 through 15. Set up the PC address to have a different last octet
from the PMSTR-4000 – an example would be to set the PC static IP address to
192.168.0.19.
Use the Modbus monitoring program to read registers 00020 through 00027. These
indicate the following:
00020 – status of unit 1 (0 = no communication, 1 = communication active)
00021 – status of unit 2 (0 = no communication, 1 = communication active)
00022 – status of unit 3 (0 = no communication, 1 = communication active)
00023 – status of unit 4 (0 = no communication, 1 = communication active)
00024 – status of unit 5 (0 = no communication, 1 = communication active)
00025 – status of unit 6 (0 = no communication, 1 = communication active)
00026 – status of unit 7 (0 = no communication, 1 = communication active)
00027 – status of unit 8 (0 = no communication, 1 = communication active)
SENSOR ISSUES
If the process control sensor (steam or hot water) does not have a valid reading, the
PMSTR-4000 will override the virtual HAND-OFF-AUTO position of each unit and force
each into HAND. The PMSTR-4000 does this since it is not possible to control the load
without a sensor connected. Placing each unit back into HAND allows them to control to
their local sensor and maintain an output. Since the units will all be in HAND, it will not
be possible for the units to be ONLINE when there is a sensor issue.

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PMSTR-4000
Quick Start Tips
September 15, 2021
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TROUBLESHOOTING MODBUS COMMUNICATION ISSUES
Here are some common issues with Modbus wiring between the PMSTR-4000 and the
connected units:
Modbus wiring is backwards – swap the wires between A+ and B- on the
PMSTR-4000 terminal block. A+ should connect to all the terminals P12.3 (in
series) and B- should connect to all the terminals P12.4 (in series).
Modbus wiring is inconsistent – some units may have the wiring connected
backwards while others do not. This may appear as only some units
communicating.
Addresses programmed into the units are not correct. These need to be set from
1 to 8. Since these are the same addresses used from the BMS Modbus port,
ensure that the BMS integrators know that these can’t be changed. Note that by
default, a new unit has an address of 247.
One of the connected units had the LEAD/LAG key pressed on the keypad and is
attempting to become master. This will cause interference and loss of
communication on the Modbus network as a network can typically only have one
master. Follow the steps described earlier in this document to disable the
LEAD/LAG key on the keypad to prevent this. The key will highlight in green or
flash in green when it has been pressed.
If the Modbus network has a long run of wiring or a lot of connected units, it may
benefit to add a 120-ohm resistor across P12.3 and P12.4 at the last unit. This is
referred to as a “termination resistor” and can help mitigate the impedance in the
large run of wiring.

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PMSTR-4000
Quick Start Tips
September 15, 2021
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MESSAGES
Once a unit is ONLINE, the NXD410TS will display a message on the home screen to
indicate the current sequencing command status. The NXTSD507HD and
NXTSD512HD will display a similar message.
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Statusmessagewhensequencedslavedisabled
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Statusmessagewhensequencedslaveenabled
Notethattheinternalstat(cut‐inandcut‐out)isstillrespectedwhensequencedslaveisenabled.
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StatusmessagewhensequencedslaveenabledbutthePCVisgreaterthanthesetpointpluscut‐out

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PMSTR-4000
Quick Start Tips
September 15, 2021
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HOT STANDBY
If sequencing is used, sensor 2 on the unit can be connected to a shell temperature
sensor to enable the hot standby feature. Setpoint 2 on the unit is configured to the
standby setpoint and whenever the sequenced slave disable command is sent, the
control will override this to maintain the standby water temperature.
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Messagewhensequencedslaveisdisabledbuthotstandbyisactive
To enable hot standby:
SENSOR SETUP  SENSOR 2  TYPE  STANDBY
SENSOR SETUP  SENSOR 2  RANGE  (choose sensor range)
SETPOINT SETUP  SETPOINT 2 SETUP  SENSOR USED  2
Enter the desired setpoint, cut-in, cut-out and PID settings as desired. Note that setpoint
1 and setpoint 2 each have individual settings.
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