New question published by HakanKilic is split to a separate thread with the subject CPU cannot communicate with the other stations.

Best regards
Min_Moderator

Hello all,

I'm wondering if someone figure this out and solve. I do have the same message as @Nick.

My Watchdog for this IM device is set to 6ms. My CPU is configured as 100% for PROFINET I/O.

This issue is running me up crazy, I have a F-Input Card attached to this IM and every time my machine is Faulted by Emergency Stop.

Hi,  this sounds like a watchdog timeout if the device goes offline then back online again quickly.  How fast are the IO's set to update in the configuration?  Usually the watchdog timeout means the devices or controller did not get updated fast enough and the timeout is usually by default 3 times update time.  So if update time is 1ms then watchdog is 3ms.  I don't know why, but many manufacturers tools always put the devices at the fastest update time (or almost) by default.  And usually with a Siemens device its 1ms.  Typically, most applications don't need the data that fast anyway.  

Usually watchdog timeouts are caused by network load issues, cabling or interference issues or resource issues (speed of processing)

As a test you can increase the update time in the configuration tool to see if this helps communications.

Your diagram does not show where the devices are actually located.  

Check cabling, is it shielded PROFINET cable or unshielded twisted pair (UTP)?  Are there other devices or voltages nearby.? Make sure you have cable separation from higher voltage signals, otherwise  you can get interference and frames are corrupted.  Especially check if you have any drives or motors near the cabling.

Also check the PROFINET installation guidelines to determine if you have grounded the system cabling properly.  grounding issues can also cause voltage on the shield connection causing interference.

PROFINET Guidelines

Is this system isolated or also connected to the office / plant network(s)?  You mention more than one system is affected, are they interconnected?  If connected have  you checked the network load?  It should not be above 50% at any time to guarantee frames would not get dropped.  You can measure load with a SNMP tool (PRTG or similar) connected to the PLCs (bandwidth utilization) at critical points.  

See the PROFINET design guideline for more information (link above).  Also it should be noted you cannot have more than 7 devices in series if your update time is 1ms with PROFINET RT.

Have you checked that you have the latest firmware in CPU and devices?  You can use the Simatic Automation Tool to update and check this:Simatic Automation Tool