Dear Experts,

I have CP341 installed in a remote rack via profibus. This CP341 will talk to a device call BCS4000 using ASCII protocol. I have done :

- HW Configuration using CP341 Point to Point Communication paramater assignment

- Programming FC's for Send and Receive and the result is as expected.

- Power OFF and ON the CPU to make sure it's working, and its working fine.

When I want to  make sure that the offline program is the same as in the CPU, I compare  offline/online and all FCs are the same except some DBs have different actual value. Looks to me is already OK.

But when I download the offline project, CPU boot and RUN without error but my CP341 not working (no TX/RX led blink).

What could be the problem?Should I write some code in OB100?

Thank you

Hello,

we don't know your project, so is very difficult to help, this can be your program problem. For first you need check if some diagnostic LEDs are light on CPU, SF or DP Failure. You can also look to CPU diagnostic buffer and search some records. I see some problem also with init of some your communication routines, as you already mention with OB100. I try bypass communication Solutions on external racks as much as possible, this is my idea.

Thank you for answering,

As I mention that after downloading, the CPU is up and RUN. Led SF, BF  are OFF.  Also in IM 153-1 there are no BF or SF .

If I toggle/modify the "send request" bit manually (separate from program) the Tx/Rx blink one time. Once i have done that toggle then I put back  in the program, then it runs continues by program (Tx/Rx Blink every one second as it programmed) .

What should be init in OB100 other then status bit of Send and Receive FCs?

thank you

Hello,

simply you can check f.ex if init was done, set some important bit in OB100 and if that bit is true (init was executed), make needed changes in your code due this (init your communication for start again as you need), also reset after that your bit programatically, you simply don't need it anymore. You must deal with your problem and correct your code.

Thank you Sir,

I will try in next visit and comeback with the result

Hi all,

It Works now!!!

It's not about the cycle scan or the OB100.

As for information that this project is to upgrade ET200U to ET200M after the Main Rack has been upgrade to S7-300 previously.

In ET200U, it's using CP521 and ASCII driver to talk to BCS4000. In the CP521 since the message frame length is vary, then the "length" parameter is 00Hex (ignore) and using END OF CHAR as the end message identification.

So in CP341 I thought I can do the same (Zeroing the Length parameter) and using the END OF CHAR for the end message identification. But id does not, I have to put numbers there. It is clearly mentioned in the " CP341 Point-to-Point Communication, Installation and Parameter Assignment Manual" page 59 that when select

"Send up to and including the End-of-text character"

The end-of-text character must be included in the data to be sent. Data is sent only up to and including the end-of-text character, even if the data length specified in the FB is longer.

Earlier during testing/debugging I put some number there and it works even after I leave that parameter blank. But when you download again the entire blocks, then this parameter become zero and that's why it does not work after download.

So the lesson here is never read the manual in hurry :)

thanks all

Hello,

there was not any sugestion about scan cycle problem, hope. Also if you have sugested that infos before (about scanning end character), situation can be better for find solution. I never use that solution with end of character condition because it can make big chaos with proper receive of messages. It has reason maybe only in messages where are used only bytes in ranges of bigger than mentioned end of character value. But this is your situation, choice.

Duris_I

Hello,

there was not any sugestion about scan cycle problem, hope. Also if you have sugested that infos before (about scanning end character), situation can be better for find solution. I never use that solution with end of character condition because it can make big chaos with proper receive of messages. It has reason maybe only in messages where are used only bytes in ranges of bigger than mentioned end of character value. But this is your situation, choice.

Hi Duris_I

Ok, noted.

Thank you