Modbus Rtu Communication - Emerson Nelson CM-1 Manual

MODBUS RTU COMMUNICATIONS
These MODBUS RTU Communication instructions are specific to the Modbus communications setup for the
CM-1 Monitoring System. Modbus communications are only provided on recent production Scanner Board
GC0698.
Wiring Instruction
From modbus master
Modbus connection wire A connects to Scanner Board GC0698 - TB5 – 7
Modbus connection wire B connects to Scanner Board GC0698 - TB5 – 9
Address settings:
•
S1 =
•
S2 =
Communications settings:
•
Baud Rate =
•
Data Bits =
•
Stop Bits =
•
Parity =
CM-1 Register Addresses/Descriptions
Write (06) address:
40000
Read (03) addresses:
40000 - 40023 Channel Flag Table*
40256 - 40264
40512
40768
*Channel Flag Bit Significance:
b15 b14 b13 b12
b15 – b10
Not Used
b9 Series Mode
b8 Parallel Mode
b7 Channel ON
b6 Channel in Alarm
b5 Alarm Pending
b4 Alarm Acknowledged
b3 Not Used
b2 Continuity Out of Tolerance
b1 Current Out of Tolerance
b0 Voltage Out of Tolerance
www.nelsonheaters.com
GA-2129 Rev. 11
Sheet 14 of 22
Jul. 2018
Ones (0-9)
Tens (10-90)
4800
8
1
None
Data = 1, acknowledges all alarms, Data = 2, resets board/all alarms
CM-1 Board ID String (ASCII)
Option Jumpers 1-8
Option Jumpers 9-16
b11 b10 b9 b8 b7 b6 b5
S2 S1
b4 b3 b2 b1 b0