WAGO Controllers now have a REST API that can be used to monitor and configure the device.
To get started, simply point your web browser to the device, with this url path. (Replace IP with your controllers IP address)
On this page is a link to download the documentation on the OpenAPI specification.
Then enter this url in the address bar:
It is recommended to use Firefox otherwise if you use Chrome you get a huge JSON file. In Firefox, you can filter by keyword. In this case I typed ‘DiagnosticInformation’.
By expanding, and finding the one you are interested in, open another tab and copy the id to the end of the url, like below for example.
https://192.168.5.29/wda/parameters/0-0-ledstates-3-diagnosticinformation
This is the IO Error when there is a KBUS error on PFC200.
This is how it looks with KBUS operational.
The interested attribute value can then be monitored. Obviously, your application would perform this check programatially, but this demonstrates the basics of the REST-API.