Hi 

I am using RS 485 communication module. It works fine . but randomly it stops sending data only . once you change CPU mode from stop to run (or power cycle) it regains its operation.

But how can i program so that if sending operation stops it automatically regains and why it stops sending sometimes first of all

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Split from CM 1241 RS422/485, when the plc is restarted that the module does not seem to transmit any values.

hi,

please provide some more information. 

To which communication partner are you sending?

How do you detect that the sending not happen?

Is there any further diagnostic? SF LED? BF LED? Diagnostic Buffer? Online-Diagnostic in TIA?

Put yourself in our shoes. How could anyone know what happens with this less information. 

hope this helps,

regards,

I can come to know that the sending operation not happening when Tx LED on CM Module stops blinking. (printscreen)

I am asking in general why sending stops randomly and what to do to prevent it in my program itself

GaJEnDrA D S

I can come to know that the sending operation not happening when Tx LED on CM Module stops blinking. (printscreen)

I am asking in general why sending stops randomly and what to do to prevent it in my program itself

How does your coding look like?

If the communication waits for a "done" signal without acting on "error", there might be this issue. If the coding detects an error (example: time-out), there should be a positive coding reaction to that.

Hi 

I dont wait for any done bit..

As in screenshot I swap the send instructions for respective RS 485 devices for every second . 2 Hz clock to make sure two time execution of send instruction on its turn.

I can detect easily when Sending stops but i need to know how to regain it.

GaJEnDrA D S

I can detect easily when Sending stops but i need to know how to regain it.

Trigger the port configuration instruction again.

Hi

Thank you

It solved . It will never stop again.

Problem was with the slaves that were not responding properly

GaJEnDrA D S

Hi

Thank you

It solved . It will never stop again.

Problem was with the slaves that were not responding properly

 HOW DO YOU FIX IT?, HOW DO YOU IMPROVE  THE CODE TO FIX THIS PROBLEM?

Gerry7

 

GaJEnDrA D S

Hi

Thank you

It solved . It will never stop again.

Problem was with the slaves that were not responding properly

 HOW DO YOU FIX IT?, HOW DO YOU IMPROVE  THE CODE TO FIX THIS PROBLEM?

 Port Config instruction as above !