I've imported pyads (Python lib to communicate through the TwinCAT library with TcAdsDll.dll. I've read here that this library has multi-threading capability.
Is it also possible to use the pyads library in multiple processes without conflict?
To avoid conflict, I have considered making a pyads wrapper which shares the ADS data to multiple Processes with multiprocessing and queues, but it would be quite some work compared to just perform:
# process1:
pyads.open_port()
self.adr = pyads.AmsAddr('192.168.2.11.1.1', 851)
data = pyads.read_by_name(adr, args)
And in a similar process:
# process2:
pyads.open_port()
self.adr = pyads.AmsAddr('192.168.2.11.1.1', 851)
data = pyads.read_by_name(adr, args):
Just running pyads.open_port() in multiple processes throws no error. I hope someone can tell me if I would receive the same data in both processes without conflicts/prioritizing.
[Edit:] We implemented our system by multiprocessing and sharing data between processes to avoid having to risk sync-problems. This works flawlessly, but introduces some dataflow and programming overhead.
From what I can see in the pyads source code and based on what I know about the TcAds dll, you should be fine with your two processes making their own connection. You can have many client simultaneous connections to a TwinCAT system. The ADS router will ensure proper synchronization of data communication.