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zamo · Junior Joined: 03 Mar 2014 Posts: 4

Dose anyone have experience with Beckhoff FC3121 profibus master PCIe card connected to Siemens CP342-5 as a profibus slave?

The data retrieved from S7 PLC is wrong, and keeps fluctuating rapidly.
TwinCAT (TC) config looks OK, and it reports that the slave is OK and has no error.
The slave is in Run mode with green LEDs.
S7 side is believed to be OK as another master from HMS-Anybus retrieved the data correctly.

Tried several versions of TC up to the latest (at the moment) ver. 2.11.2305.
Here is a zip file with two graph pics of the two masters showing how the "same" data looks like in each case:

https://drive.google.com/file/d/1ijlx6AXA3FX8GqgJjwWlFMxPxqT4xN9F/view?usp=sharing

Thanks,
Hos

drkarjiee · Junior Joined: 25 Oct 2018 Posts: 6

Did you install TX1100 I/O driver?
https://www.beckhoff.com/english.asp?pc_cards_switches/fc3121_fc3122.htm

Do you have terminal Resistance on Slave just in case?

https://support.industry.siemens.com/cs/document/1158693/s7-cps-for-profibus-configuring-and-commissioning
https://support.industry.siemens.com/cs/document/21628388/what-are-the-differences-between-an-integrated-dp-interface-of-my-cpu- (e-g-cpu-315-2-dp)-and-the-dp-interface-of-the-cp-342-5
https://support.industry.siemens.com/cs/document/15007089/notes-on-linking-a-cp342-5-as-dp-slave-to-a-dp-master-with-step-7
FDL communication with SDA service via PROFIBUS CPs and Send/Receive interface
https://support.industry.siemens.com/cs/document/20987711/fdl-communication-with-sda-service-via-profibus-cps-and-send-receive-interface

Need more data about your configuration!!!

zamo · Junior Joined: 03 Mar 2014 Posts: 4

The "TX1100" product code refers to the license level of TwinCAT (i.e., I/O, PLC, NC, etc). The installation of fieldbuses drivers is automatic and the user has no control to select which fieldbus driver to install or not. Beside, the card is automatically recognized and working without error/warning. so the short answer: yes.

There are 6 similar slaves on the bus. They don't have built-in terminators, but the connected profibus connectors have. All terminators on the line are set correctly (either ON or OFF according to cabling). The master can see & communicate with all the slaves.

I have used this slave many times before without problems, but I will review the links you provided.

Configurations:

Beckhoff: "Pics, TwinCAT Config.zip" :
https://drive.google.com/file/d/1j6sI8lYos3a3HehT4uzsNWQHrrMejKvp/view?usp=sharing
If you have TwinCAT, I can post its config file (not pics as above)

Siemens: In preparation

zamo · Junior Joined: 03 Mar 2014 Posts: 4

Pics, S7 Config.zip

https://drive.google.com/file/d/1dchJlYul6jzy5ppNaKPrwuxXCdQv0EMx/view?usp=sharing

zamo · Junior Joined: 03 Mar 2014 Posts: 4

I owe you a deep and sincere apology.

Let me try to make the story short:
From the beginning, due to security reasons, I wasn't allowed to access the PLCs (which are several thousand miles away) remotely.
I was allowed only remote access to the PC in which TwinCAT is running.
Any modification I would need to do with any of the PLCs, I had to send it to a person in the field to apply it, then I would investigate the results in TC.

Due to the erroneous data received by TC, I suggested modifying one of the PLCs to send known-fixed values, hoping that I can locate these values in the PFB card memory (suspecting wrong or shifted addresses).
After getting the OK that the modification was implemented, TC was still showing erroneous values... Here I posted my original msg.
With the lack of new ideas, I insisted on accessing the PLCs myself...Finally, I got the OK.

Just a few minutes after access, I found that my modification was wrongly applied: instead of copying blocks from one project to another, they edited the existing blocks with code from the original blocks (not the modified ones). So, I was under a "wrong" impression that the values are fixed in the PLC while they are changing in TC.
After correcting this mistake, TC shows the known-fixed values as they are but bytes-reversed.
Applying "byte-swapping" function, TC and the linked software show the data correctly.

Please accept my apology and I'm really thankful for your help.
Hos