Omron E5AC, Communications Manual

Page: 84 / 224

4 Modbus Communications Procedure
4 - 4
E5@C Digital Temperature Controllers Communications Manual (H175)

Normal Response Frame

Error Response Frame
4-1-2 Response Frame
Slave address
The number specified in the command frame is entered as-is. This is the unit
number of the Unit returning the response.
Function code
This is the received function code with the hexadecimal value of H'80 added
to indicate that the response is an error response.
Example: Received function code = H'03
Function code in response frame when an error occurred = H'83
Error code This code indicates the kind of error that occurred.
CRC-16
Cyclic Redundancy Check
This check code is calculated with the data from the slave address to the end
of the data.
The check code is 2-byte hexadecimal.
CRC-16
1 1
Data
CRC-16 calculation range
2 bytes
Slave
address
Function
code
CRC-16
1 1 1
CRC-16 calculation range
2 bytes
Slave
address
Function
code
Error
code