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When using a Unity Premium PLC, what function block would I use for retrieving diagnostic information from a Modbus slave device?


The SEND_REQ function block is used for retrieving diagnostic and maintenance information from  a Modbus slave device....
 
Modbus Request
Function Code / Sub Function Code
Communication Function
Exception status
16#07
SEND_REQ
Diagnostics
16#08/16#xx
SEND_REQ
Event counter
16#0B
SEND_REQ
Connection event
16#0C
SEND_REQ
Slave identification
16#11
SEND_REQ
 
The diagnostics and maintenance information are shown below:
Designation
Function code / sub-function code
Read exception status
16#07
Echo
16#08 / 16#00
Initialize module
16#08 / 16#01
Read the diagnostic registers of the PLC
16#08 / 16#02
Change end of frame delimiter (ASCII mode)
16#08 / 16#03
Switch to listening mode
16#08 / 16#04
Reset counters
16#08 / 16#0A
Number of messages received without CRC error
16#08 / 16#0B
Number of frames received with CRC error
16#08 / 16#0C
Number of exceptional responses
16#08 / 16#0D
Number of messages addressed to the PLC
16#08 / 16#0E
Number of broadcast messages received
16#08 / 16#0F
Number of correct responses
16#08 / 16#10
Number of messages received in listening mode
16#08 / 16#11
Number of invalid characters received
16#08 / 16#12
Read event counter
16#0B
Read connection event
16#0C
Read identification
16#11



 
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