Modbus binding fail notification

I use the modbus binding, both TCP and RTU. Sometimes there are errors and it looks that binding stops working (I’m not sure what happen, but today I had to restart openhab service to make it work again. I suspect that a DNS failure was the reason). What would be the best option to get notified when anything goes wrong in this or any binding?


You might start here, but a lot depends on the nature of your mystery problems.

Hi thanks for you reply. I’ve read the posts your mentioned, and there are couple of things that are not clear to me. Firstly let me describe quickly the usage of modbus binding:

The openhab machine uses both serial and tcp. Serial is connected to slaves that send info regarding sensors (door contacts, movement sensors, fire sensors, …) and tcp is for some low importance data such as temperature readings.

My mysterious problem of yesterday, was a simple and common network (Ethernet) failure. The machine that the tcp things connect to became silently unavailable, and after a few hours, no modbus data was being updated, including the serial slaves. So I’m assuming the binding staled. Although I couldn’t see anywhere the conditions to stale this binding.

If my assumption is correct, ie the binding staled, what workaround can use to mitigate the problem?

What version are you running? Newest binding has I believe some small improvements in serial exception handling.

As described in the linked post, if you have many modbus devices and some fail, you can enter a period of accumulating delays, unless you take steps to manage it.