Error in communication about p-net

[pyhys]

Normally the p-net stack on Linux sends a cyclic data frame approx every 3 ms. When this increases to around 7 ms (due to load), the Simatic PLC sends an alarm indicating that the timing requirements not are met. Then the cyclic communication is shut down for a few seconds, until a new start-up happens.

We are looking into using the PREEMPT_RT patches to improve the Linux real time properties.

[pyhys]

You need to tweak the Linux real time properties to fulfil the Profinet timing requirements. We have started to document this on https://rt-labs.com/docs/p-net/linuxtiming.html