Modbus Serial - 750-652 - Slave detection/packet count

CODESYS
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1

Hi all,

I have had some issues trying to implement some form of a packet/frame count on a Modbus Serial Master setup with your 750-652 card, there is one slave on the bus.

I wanted to use the packet count to detect when the slave is active/alive, and when it is not, I can wipe the data registers to zero (currently they stay with last value, incorrectly).

I cannot see, with my knowledge a simple variable or declaration within the FbMbMasterSerial FB that I am using from the WagoAppPlcModbus library that would help me achieve this, or maybe I am missing something.

Any ideas folks? Much appreciated.

2

Hello,
If your 652 is used as a Modbus Master you should be able to get the Timeout error in case of a disconnected slave / not active one. With this error you could left the data as it or reset everything to whatever state you like.