Hi,

I don't know if this is the correct forum to post my request but hopefully you guys can help.

I have 6ES7241-1CH32-0XB0 CM 1241 RS422/485 module. I am having an issue when the plc is restarted that the module does not seem to transmit any values. Only once i cycle the plc (stop >> run) does it start working. Then everything is fine unitl you restart again.

Any ideas ?

Im using a WTB485 weighing module and transmitascii.

To add some more information, i have replaced themodule to confirm that its not hardware.

Also the previous machine was built with6ES7241-1CH31-0XB0 and this problem did not occur on that module.

thanks in advance

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New subject after splitting from CM 1241 RS485 Problem.

Hi,

Thanks for the reply,

Ive managed to get the older module 6ES7 241-1CH31-0XB0 and as mentioned then all works fine.

Unfortunately i do not have the time on these machines to test further so have elected to leave it and then future units ill solve the problem.

To answer your question though, on startup there are no values in the buffer, also, there is no evident difference between when its reading and when its not reading other than there is a string value on the buffer.

The code is written to flop between read and write operations on clock pulses and this seems to cause hassles with the new unit. The idea for future units is then to seperate the read and write functions more and also to put the wtb485 module into continous data and then just interrupt that with the tare/calibrate/zero functions.

But thats a problem for another day .. i will update this thread then once ive figured it out.

Hi All,

Just an update,

found that with the newer module if I set the port config and then send it on every start-up (even though this is done in the hardware) it seems to take care of the issue.

The Ptp setup is also slightly different from before, now I use the send to trigger the receive and vice versa with a delay. This ensures I don't get any send / receive errors.

Just glad everything is working now  :)

Thanks

New question published by GaJEnDrA D S is split to a separate thread with the subject CM 1241 RS422/485 randomly stops sending data.

Best regards
The Helping Hand