Can you please share how you did the modbus communication in PCS7 using FB7 & FB8?

I had written logic in OB1 using FB7 and FB8 and prepared Send and Receive DBs. But the problem I am facing that everytime I make changes in the DB, I have to download all the blocks. And another issue is even I do make changes in the SEND DB, the values are not changing even after download. 

Thanks,

GJ

Hi Gaurav

Here is link for CP340/CP341 modbus RTU program without dongle for S7-300.You can try the same in PCS7 .

Although these blocks will not generate any faceplates but still you can use them to read values from modbus master/slave.

https://support.industry.siemens.com/tf/gb/en/posts/modbus-rtu-master-for-cp340-341-441-x-no-dongle-required/111091/?page=0&pageSize=10

Thanks

Ravi

New question published by HarePrasath is split to a separate thread with the subject S7HMODM3 library for RS485 communication.

Best regards
Jen_Moderator