Device with poor connectivity

[hybrid]

Hi there,

I wondering how you would suggest dealing with a modbus device that has poor connectivity. It could be offline 25-50% of the time.

I am displaying the values in a scheme and table in web portal but obviously when the device is offline , the values read as zero.

Ideally, I’d like the last good data received to be displayed, along with a timestamp of when that data is from? Is this possible ?

[Mikhail]

Hi,
Please provide logs of communication line when the device is offline.
Also provide a screenshot of the values when the device is offline.

[hybrid]

See log here https://expirebox.com/download/9c27e6663c6202d857c051a7687e7e5e.html

Screenshots here https://imgur.com/a/JuJgC

[Mikhail]

Hi,
Thank you.
The expected behavior in this case: values and statuses of tags are zero when connection is broken. Does it work as expected or not?

“Unable to request because connection is not established” – probably, the device disconnects from the PC. If this is a usual LAN, you should check communication with Modbus Simulator installed on another PC. If it works normal, the problem is in the device.

[hybrid]

I understand the software is working as designed. Is it possible for the last good value (last value when device is connected) to display. Instead of defaulting to zero.
Also is it possible to display a timestamp of the when the device was connected last?

[Mikhail]

Instead of defaulting to zero.

You need a formula of input channel. Try this: Stat > 0 ? Cnl : Val()

[Mikhail]

Also is it possible to display a timestamp of the when the device was connected last?

You can also implement it using formulas.

I’d like to say that the connection is not stable, it is not normal, you should find the cause and make the connection better.

[Author]

Posts