FORM NO.:6U6K-B01E-NB-EN
JOHNSON CONTROLS
128
MODBUS PROTOCOL
TABLE 42 - DEFINITIONS
NO. IT EM DESCRIPTION
1 Data Flow
Communication Baud rate: 9600bps;
8-N-1: 1 start bit,1 stop bit, check bit-none, 8 data bits;
Modbus-RTU Protocol;
CRC: Cyclic Redundancy Check;
Hexadecimal data.
2 Master - Slave
Modbus as master;
1# microboard as slave.
3
Temperature (Control
Panel)
Unit: 0.1 °C;
Actual temperature = Register value/10;
e.g.: Cool RT Setpoint Register value 0x0078 = 120, then th e setpoint is 12.0 °C.
4 Temperature (VSD)
Unit: 0.1 °C;
Actual temperature =
Register value/10.
5 Pressure
Unit: kPa;
Actual pressure = Register value.
6 EEV Opening Degree
Unit: Step;
Actual EEV Ope ning Degree = Register value.
7 Fan Spe ed
Unit: RPM;
Actual Fan Speed = Regi ster value.
8 Compressor Speed
Unit: 0.1 RPS;
Actual Compressor Speed = Register value/10.
9 Access Mechanism
BAS parameter setpoint may exceed unit default range and it is requ ired for BAS t o
read the setpoints from the microboard.
10 BAS Enable
The BAS Modbus addresses of subord
inates are set through HMI;
Set the c orresponding parameters in HMI to enable and disable the BAS Start/Stop
and Operating Mod e functions.
11 Start/Stop Status
The Start/Stop Command (Register value = 0) is only used to start/stop the u nit;
Actual Start/Stop Stat us is a ccessible by reading Register value = 100.
SECTION 11 – MAINTENANCE
Cooke Industries - Phone: +64 9 579 2185 Email: sales@cookeindustries.co.nz Web: www.cookeindustries.co.nz
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