Hi there,

Currently I have a line profinet network about 500m long in total. I found sometimes the profinet devices at the end of the line will time out (cycle time 2ms).

I wonder is it because the bad profinet plugs or the physical length of the network is too long, hence I have to make the cycle time bigger. Let's say 4ms??

Kind regards,

Wilson

Hello cbw_2000,

500m is quite a distance. According to Ethernet specifications you need at least 4 switches (one every 100m) to maintain signal quality. In real world with Profinet you should calculate for a switch every 70 to 80m. Did you take that into account?

See also here:

MAXIMUM LENGTH FOR REMOTE I/O ON PROFINET

regards

Thanks eisenpferdreiter,

I have about 44 switches in between. And the 500m is the estimated value from the first one (master) to the last one. The safety PLC is connected to the first one, and one last safety remote IO connected to the last switch. Hence I wonder is it still ok for the 2ms scanning time for this kind of distance, or should I set it to 4ms for example.

I hope I explain my question clearly.

Thanks & regards,

Wilson