Thermo Scientific 5028i Instruction Manual page 308

MODBUS Protocol
Function Codes
C-4 Model 5028i Instruction Manual
Note The values reported may not reflect the state of the actual relays in
the instrument, as the user may program these outputs for either active
closed or open.
s
Request
Function Code
Starting Address
Quantity of Outputs
Unit Identifier
Response
Function Code
Byte Count
Output Status
*N = Quantity of Outputs / 8, if the remainder not equal to zero, then N=N+1
Error Response
Function Code
Exception Code
Here is an example of a request and response to read outputs 2–15:
Request
Field Name
Function
Starting Address Hi
Starting Address Lo
Quantity of Outputs Hi
Quantity of Outputs Lo
1 Byte 0x01 or 0x02
2 Bytes 0x0000 to maximum allowed by instrument
2 Bytes 1 to maximum allowed by instrument
1 Byte 0x00 to 0xFF (Passed back in response)
1 Byte 0x01 or 0x02
1 Byte N*
N Byte N = N or N+1
1 Byte 0x01 or 0x02
1 Byte 01=Illegal Function, 02=Illegal Address,
03=Illegal Data, 04=Slave Device Failure
(Hex)
0x01
0x00
0x02
0x00
0x0D
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