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SECTION 36 - SOFTWARE ENHANCEMENTS
FORM 160.54-M1
ISSUE DATE: 10/25/2019
JOHNSON CONTROLS
JCI COMPANY CONFIDENTIAL
36
MOTOR COMMUNICATIONS PROTOCOL
SETPOINT
On new production chillers before March 2007, the
VSD Adaptive Capacity Control (ACC) board com-
municates with the microboard COM5 serial port us-
ing YORK protocol. After this date, on new production
chillers, the ACC functionality is contained in the mi-
croboard and the ACC board is not present. On these
chillers, the VSD logic board communicates directly
with the microboard COM2 serial port using Modbus
protocol. To allow this software to accommodate new
production chillers and earlier chillers, this software
allows selection of either YORK or Modbus protocol
when VSD-50Hz/VSD-60Hz is selected for the motor
drive type setpoint. When used with Modbus protocol,
microboard (P/N 031-02430-001) is required (refer-
ence SI0155). The protocol selection enables the ap-
propriate serial communication port:
• YORK enables COM5
• Modbus enables COM2.
The hardware present determines which protocol
should be selected (reference SI0155): If the ACC
board is used, select YORK. Otherwise, select Mod-
bus.
With Modbus protocol, the device that the microboard
serially communicates with is assigned an address. On
VSD applications, this device is the VSD logic board.
Whenever the microboard is reading or writing to this
board, it transmits this address. If the transmitted ad-
dress matches the address assigned, the logic board
responds. Otherwise, it ignores the command/request.
The address assigned to the VSD logic board is 1,
which is done by the positioning the VSD logic board
Modbus address switch SW3 Position 1 to ON and
setting the Motor Node ID setpoint to 1. If these two
values are not set to the same number, the VSD logic
board will not communicate with the microboard.
NEW SETPOINTS
The following new setpoints are programmed on the
SETUP Screen.
Motor Communications Protocol
Access Level Required: SERVICE
Only displayed when VSD-60Hz or VSD-50Hz is se-
lected for motor drive type setpoint, which allows the
service technician to enable the appropriate serial com-
munications port for communications to the VSD. En-
tered as YORK to enable COM5 (J15) or Modbus to
enable COM2 (J13). Selection is based on hardware
and interface. If ACC board is used, select YORK. Oth-
erwise, select Modbus. Microboard (P/N 031-02430-
001) must be equipped with 128KB BRAM (P/N 031-
02565-000) to select Modbus. Chiller must be stopped
with the start-run-stop switch in the stopped position to
change this setpoint.
Motor Node ID
Access Level Required: SERVICE
Only displayed when Modbus is selected for the mo-
tor communications protocol setpoint above, which
Allows the service technician to enter the Modbus
address of the VSD logicboard. Must be set to 1. The
VSD Logic board Modbus address switch SW3 must
also be set to 1. Chiller must be stopped with the start-
run-stop switch in the stopped position to change this
setpoint.
The following screens are affected by this new proto-
col selection:
• COMMS screen.
When MODBUS COMMS are selected, the
COM2 SETUP key on the COMMS screen is not
displayed.
• MODBUS DIAGNOSTICS Screen.
When Modbus Protocol is selected, the VSD
COMMS screen is replaced by the DIAGNOS-
TICS VSD (Modbus) Screen. A RESET COUN-
TERS key is present allowing the error counters
to be reset to zero. This screen displays the fol-
lowing Modbus communications error counters:
Panel to VSD
VSD to Panel
FTR to VSD (if IEE 519 filter present and
enabled)
SI0164 - SOFTWARE ENHANCEMENTS EFFECTIVE APRIL 2007 (CONT'D)