sending websocket commands that follow background curve

[jwmelvin]

I implemented inlet-temp control in my roaster, and would like to have Artisan send the desired values based on a background curve. The roaster connects over websocket and I control the firmware so can adapt to whatever Artisan wants. My default is, e.g., {"command":"INLET","value":190}.

I know I can replay events, but is there a more general way, analogous to Artisan's PID SV-from-background mode? I'd like the value to update every second, like the PID background mode. Maybe this is a configuration that I haven't yet figured out?

I had background following working when I used Artisan's built in PID, but closing the loop in my machine improves its performance a lot, as it can run a faster and tighter-controlled loop; inlet temp in my air roaster is very quick to respond.

I did read some blog posts but only see events as the background playback. Any help here would be really appreciated.

[MAKOMO]

So you would like to send IT readings from the background profile via WebSockets to your device? I think this is not directly possible. However, you should be able to send the backgrounds BT {BTB} and ET {ETB} via a corresponding Sampling WebSocket sendcommand in the Events dialog once per sampling interval. Thus you would need to arrange things to map your IT to Artisans ET channel and this should be possible.

[jwmelvin]

Okay, so encode the desired IT as the background's ET?

And then I could use the sampling command: send({{"command":"INLET","value":{ETB}}}) ?

Thank you so much for the help.

[MAKOMO]

Okay, so encode the desired IT as the background's ET?

No. I thought you need to transfer the backgrounds IT to your controller. As you can send only BT or ET you could organize things such that the ET contains the IT and send that one.

The foreground IT should be already known by your controller as it measures it and sends it to Artisan, right?

Maybe I misunderstood something.

And then I could use the sampling command: send({{"command":"INLET","value":{ETB}}}) ?

Yes, this would send the backgrounds IT reading at the time of sampling to your controller.

Thank you so much for the help.

[jwmelvin]

Sorry to take up repeated cycles. I meant that the background ET curve will hold my desired IT, which will allow the sampling feature to use those values as {ETB} for the command.

These background curves will be generated by a script; assuming I understand the relationships, if I were to use an actual (i.e., recorded) profile as the background, then this setup would send whatever the measured ET values were as the desired IT values. I'm not intending to do so, I just want to make sure I understand.

[jwmelvin]

Brief follow up to report that I adopted the more conventional approach of ramped-events from the background. It seems to fit Artisan’s style a little better and is a nice prebuilt mechanism. Using background profiles with ~8 events is plenty fine grained with Artisan’s ramping feature.

[MAKOMO]

Thanks for this followup