Data Presentation For Function Code 03 And 04; Function Code 06 - Preset Single Register; Function Code 08 - Preset Single Register; Table 16 Byte Representation For Function Code 03 And 04 - ABB M101 Manual

FU N CT IO N CO D ES
AN D 0 4

8.5. Data Presentation for Function Code 03 and 04

Function code 03 and 04 using a 16 bit modbus register. In the first byte of register is high
part of data in second byte is the low data part.
Bit Number
Register n

Table 16 Byte representation for function code 03 and 04

A float value has 4 bytes and uses two 16-bit Modbus registers. See following table:
Bit Number
Register n
Register n+1

Table 17 Byte representation for Float

In case Mapping Tool parameter "Float Register Big Endian" is set to "No" data presentation
of float value is as follows:
Bit Number
Register n
Register n+1

Table 18 Byte representation for Float Big Endian

8.6. Function Code 06 – Preset Single Register
Function code 06 allows control system to modify the contents of a single output register.
Any output register that exists within the system can have its contents changed by this mes-
sage i.e.
Switching Commands, other commands
• The valid address range: 40001-49999
Outgoing commands utilizing FC06 are always sent, regardless of any change to the
command value.
8.7. Function Code 08 – Preset Single Register
The purpose of the loop back test is to test the communication between Master and Slave
station. The data passed in the request data field is returned (looped back) in the response
(Sub-function 0000). The entire response message should be identical to the request.
1TG C 9 0 8 0 0 4 M 0 2 0 1
15 - 8
Data High
15 - 8
Data High
Data Low-High
15 - 8
Data Low-High
Data High-High
D ATA PR E S E NTAT IO N F OR FU N CT IO N CO D E 03
7 - 0
Data Low
7 - 0
Data Low
Data Low-Low
7 - 0
Data Low-Low
Data High-Low
41