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3.3. Preset single register (06H)
Function Code 06 enables users to change the content in a single register. Any writable single register inside the controller can use this
function code to change its value. For example, preset the overload acting current register value as 03E0H and address as 0500H.
Downstream message (from host to slave):
Address
Function
code
Variable start
address
High byte
Variable start
address
Low byte
Variable value
High byte
Variable value
Low byte
Check code
Low byte
Check code
High byte
03H
06H
05H
00H
03H
0E8H
88H
5AH
Table 3.6 Function Code 06 downstream message example
A normal response to preset a single register request is to transmit the received data back after the register value is changed.
Upstream message (from slave to host):
Address
Function
code
Variable start
address
High byte
Variable start
address
Low byte
Variable value
High byte
Variable value
Low byte
Check code
Low byte
Check code
High byte
03H
06H
05H
00H
03H
0E8H
88H
5AH
Table 3.7 Function Code 06 upstream message example
3.4. Preset multiple registers (10H)
Function Code 16 (by decimal) or 10H (by hexadecimal) enables users to change the contents in multiple continuous address registers.
All the writable parameters that can be written with Function 06 can be written with this function code.
The following example is to clear the maximum current value of phase A, B and C of Slave No. 17. The addresses are 408H, 409H, and
40AH, 3 variables in total, occupying 6 bytes.
Downstream message (from host to slave):
Device
address
Function
code
Variable start
address
High byte
Variable start
address
Low byte
Variable number
High byte
Variable number
Low byte
Number of variable
bytes
11H
10H
04H
08H
00H
03H
06H
Variable value
High byte
Variable value
Low byte
Variable value
High byte
Variable value
Low byte
Variable value
High byte
Variable value
Low byte
Check code
Low byte
Check code
High byte
00H
00H
00H 00H 00H 00H 4CH
0CAH
Table 3.8 Function Code 16 downstream message example
Upstream message (from slave to host):
Device
address
Function
code
Variable start
address
High byte
Variable start
address
Low byte
Variable number
High byte
Variable number
Low byte
Check code
Low byte
Check code
High byte
11H
10H
04H
08H
00H
03H
02H
6AH
Table 3.9 Function Code 16 upstream message example
3.5. Communication diagnosis (08H)
Function code 08 provides users with a series of conditions to test and verify communication system between the host and controller or
check for errors in the slave.
This function code uses a sub-function code (2 bytes) to define test types. Most diagnostic tests use a 2-byte data area to send
diagnostic data and control information to the controller. Some diagnostic data is returned by the controller and placed in the normal
response data area.
The following example is to check the number of CRC check errors received by Slave No. 17 for the address, with the sub-function code
of 0CH.
Downstream message (from host to slave):
Device
address
Function
code
Sub-function
code
High byte
Sub-function
code
Low byte
Diagnostic data
High byte
Diagnostic data
Low byte
Check code
Low byte
Check code
High byte
11H
08H
00H
0CH
00H
00H
1AH
60H
Table 3.10 Function Code 08 downstream message example
Instruction Leafl et
Effective September 2022
IZM6 Series Air Circuit Breaker
Operating Instruction Leafl et