Communication stops on device timeout

[Jure]

I have two devices on communication line, both of them modbus. Everything works OK if both are working, but If i turn off one communication with it times out and whole communication line stops:

http://imgur.com/a/aA4cH2k

Should i change settings to prevent this, or what would be solution?
http://imgur.com/a/BP6llmo

[Mikhail]

On the screenshot the line seems working.
Also please provide a screenshot of your communication channel properties.

[Jure]

If you look at last line it says:”Establish a TCP connection with 192.168.95.112:502″ it is waiting there for few seconds without communicating with other device which is still turned ON.
With turning off the device i mean turning off the simulator on some PC. Other device that is PLC is still working.

With communication channel you mean this?
http://imgur.com/a/motJS49

[Mikhail]

Line Parameters – Main Parameters, then Communication Channel group box and the Properties button.

it is waiting there for few seconds without communicating with other device which is still turned ON

What date and time on your screenshot?

[Jure]

Settings:
https://imgur.com/Oz20xiY

Communication log:
https://imgur.com/TeDtNY0

As you can see it takes 25 seconds between two reads. But it should read every second. So if I send command in this 25 second window it won’t be sent. Should every device be on it’s own line?

• This reply was modified 4 years, 7 months ago by Jure.

[Jure]

Sorry second screenshot was wrong:
https://imgur.com/a/XnMcZ6S

[Mikhail]

It takes time for waiting 192.168.95.112 at 08:07:43.
I don’t see the 1st screenshot that may be contains communication channel properties. Could you post it again?

[Jure]

Correct, it waits because 192.168.95.112 is offline. But because of that 192.168.95.10 is unresponsive.

I hope that properties work now:
http://imgur.com/a/mV5s7a3

[Mikhail]

You could increase the Reconnect parameter to 30 or 60, for example, to reduce latency when a device is offline.
Also it can be a good idea to split polling into several communication lines that work in parallel.

[Author]

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