Thermo Scientific 146i, Instruction Manual

Page: 337 / 340

MODBUS Protocol
Function Codes
Thermo Fisher Scientific Model 146 i Instruction Manual C-7
The contents of register 10 are shown as the two byte values of 0x02 0x2B.
Then contents of registers 11–13 are 0x00 0x00, 0x00 0x64 and 0x00 0x64
respectively.
The force (write) single coil function simulates the activation of the digital
inputs in the instrument, which triggers the respective action.
This function code is used to set a single action to either ON or OFF. The
request specifies the address of the action to be forced. Actions are
addressed starting at zero. Therefore, action number 1 is addressed as 0.
The requested ON/OFF state is specified by a constant in the request data
field. A value of 0xFF00 requests the action to be ON. A value of 0x0000
requests it to be OFF. All other values are illegal and will not affect the
output. The normal response is an echo of the request, returned after the
state has been written.
Request
Function code 1 Byte 0x05
Starting Address 2 Bytes 0x0000 to maximum allowed by instrument
Output Value 2 Bytes 0x0000 or 0xFF00
Response
Function code 1 Byte 0x05
Starting Address 2 Bytes 0x0000 to maximum allowed by instrument
Output Value 2 Bytes 0x0000 or 0xFF00
Error Response
Function code 1 Byte Function code + 0x80
Exception code 1 Byte 01=Illegal Function, 02=Illegal Address,
03=Illegal Data, 04=Slave Device Failure
Here is an example of a request to write Coil 5 ON:
Request
Field Name (Hex)
Function 05
Output Address Hi 00
Output Address Lo 05
(0x05) Force (Write)
Single Coil