I’m using RT pThreads in a native C++ application on the PLCnext. Is there documentation / best practice on how to set the priorities for this kind of threads?
I’ve seen problems (Watchdog error) during startup, when the priority of the RT-Thread is to high. After lowering them the problem was gone.
So my questions is like: How low can I go and why?
Hello svenplc,
If possible, please don’t use the RT-Prio. If this is necessary for various reasons, please note that the current FW uses the RT-Range (1-99).
The PLCnext Runtime requires some CPU respources during startup - there is an error if the PLCnext Runtime does not start up within a certain time.
There are no guidelines on how to avoid this problem - it will depend on a combination of what the other task is doing while the PLCnext Runtime is starting, and the prioirty of that other task.
One way to avoid the problem completely can be to delay the startup of other tasks for a short period after boot, or until it can be confirmed that the PLCnext Runtime has finished starting up. This is a good idea in any case, because the external application probably needs resources from the PLCnext Runtime to be available (e.g. gRPC services).
I hope it helps.
BR Eduard