Specifications

© 2010 Cypress Solutions Complete Manual: CTM-15X Firmware 1.3.0
Open CTM (Revision D)
173
MODBUS Messages
Where:
0xSS is the current state of the 4 digital outputs
Bit 0 represents output #1
Bit 1 represents output !#2
Bit 2 represents output #3
Bit 3 represents output #4
11.2 Set Digital Output
In MODBUS term this is called “write coil” and has function code 0x05.
Request message: 0xII 0x05 0x00 0xWW 0xSS 0x00 0xZZ 0xZZ
Where:
0xII is the modem’s assigned MODBUS ID
0xWW is the output to be set: range 0x00 to 0x03 corresponding with outputs 1 through 4
0xSS is the output set state: 0x00 = off, 0xFF = on.
0xZZ 0xZZ is the CRC checksum for this message
Response: 0xII 0x05 0x00 0xWW 0xSS 0x00 0xZZ 0xZZ
Where:
0xWW is the output set: range 0x00 to 0x03 corresponding with outputs 1 through 4
0xSS is the set state of the output: 0x00 = off, 0xFF = on.
11.3 Read Digital Inputs
In MODBUS term this is called “read discrete inputs” and has function code 0x02.
Request message: 0xII 0x02 0x00 0x00 0x00 0x06 0xZZ 0xZZ
Where:
0xII is the modem’s assigned MODBUS ID
0xZZ 0xZZ is the CRC checksum for this message
Response message: 0xII 0x02 0x01 0xSS 0xZZ 0xZZ
Where:
0xSS is the current state of the 6 digital inputs
Bit 0 represents output #1
Bit 1 represents output #2