Disclaimer: I have little experience with MQTT
We’re starting a new project using MQTT to pull data from oollldd PLCs out in the field back into a new Ignition gateway. The PLCs are most serial talking to a new RedLion protocol converter which will be the MQTT field devices. We have MQTT Engine and Distributor running in Ignition.
My question is about tags and backfilling.
My thoughts and hopes would be to just consider the MQTT Engine as a single “Device”, where I would create tags as normal in an Ignition tag provider (e.g. ‘default’) that would reference the MQTT tag provider tags. The main reason is for the ability to control the tags centrally: make UDTs, configure tags with config (eng ranges, units, format, history, alarms, etc. the normal stuff). I don’t see this being easily possible from MQTT. The fields are all there in the MQTT tag provider tags, however the only config sent down from the Redlions is the name and the address. No other config can be attached. I also can’t add extra Ignition memory tags which might be required into the MQTT structures. If I had to do this in MQTT tags, then I would need to configure every single tag manually, no import/export capability as far as i can tell.
For the Ignition tag provider tags, I would use ‘Reference’ tags in Ignition tag provider to reference the MQTT tags.
That all being said, the thing we need is backfilling capability… which doesn’t look like it works when using reference tags, unless someone knows how I can do this?
As a last resort, I thought that I could manually configure history (and painfully) on the MQTT tags required and use these purely to store history. Then create the Ignition tp tags as well. It would be a bit of a pita creating charts and things…
Am I going about this the wrong way? misunderstanding something obvious? Cheers!