AUMA EPAC - Register Details for Modbus Communication; Modbus Function Codes and Registers

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6. REGISTER DETAILS FOR MODBUS COMMUNICATION
Modbus is a two-wire serial communication protocol that is used for information
exchange between DCS/AIMS and our actuators. The details needed for the Modbus
communication such as Function Code, Address, Data to be written is listed below.
Function Code Details (as implemented by AUMA):
DESCRIPTION
VALUE
1. READ COIL STATUS
0x01
2. READ INPUT STATUS
0x02
3. READ HOLDING REGISTERS
0x03
4. READ INPUT REGISTERS
0x04
5. FORCE SINGLE COIL
0x05
6. FORCE MULTIPLE COIL
0x0F
7. PRESET SINGLE REGISTER
0x06
8. PRESET MULTIPLE REGISTERS
0x10
9. DIAGNOSTICS
0x08
a. LOOP BACK
0x00
b. CLEAR COUNTERS
0x0A
c. RETURN BUS MESSAGE COUNT
0x0B
d. RETURN BUS COMMUNICATION ERROR COUNT
0x0C
e. RETURN BUS EXCEPTION ERROR COUNT
0x0D
f. RETURN SLAVE MESSAGE COUNT
0x0E
g. RETURN SLAVE NO RESPONSE COUNT
0x0F
Function Code 1, 5 & 6: The register details for read & write operations associated with the
function codes 1, 5 & 6 (coil status) are as below.
DESCRIPTION
ADDRESS IN HEX
1. REMOTE OPEN
0x0000
2. REMOTE CLOSE
0x0001
3. REMOTE SET POINT
0x0002
4. REMOTE SW POSITION
0x0020
5. OFF SW POSITION
0x0021
6. LOCAL SW POSITION
0x0022
Note: The data values of the function code 1, 5 & 6 are to be indicated in binary (1/0).