CPU goes to STOP on power up

Good Afternoon,

I'm setting up a new Robot Cell with a CPU 313C-2 DP. Its using Profibus to communicate with a KUKA Robot.

If I turn the robot on first, wait for it to fully boot up, and then power on the PLC, I have no problems. But if I turn on my PLC first, then turn on the Robot, once the robot boot is complete the PLC stays in STOP mode.

It is easy to fix at the time, all i have to do is switch it to stop, then back to run and everything starts to work again. This will become a hassle once the cell is ready for production.

Does anyone know how to fix this so that is a Slave is not powered on the PLC will not go into stop mode?

This happened to me with another cell about 2 years ago, but I can't remember how I fixed it. I've tried comparing the programs and configurations but have been unsuccessful at finding the deciding factor.

Thanks

Hello,

You can find the source of the problem using diagnostic buffer (CTRL+D in simatic manager).

Here you can find also indication on what error OB you have to download in the cpu to prevent stop.

Best Regards

Hi,

you can also check the B,I and L-Stack when CPU goes to stop.

Look on pdf-page 491:

https://support.industry.siemens.com/cs/ww/en/view/45531107

Regards,

Towome

Dear M-TITAN

Your program should have the following blocks 

OB82 , OB86 , OB122 

try them and a feedback will be appreciated.

Regards,

Ahmed