I am wondering if this is a bug. On my Ender3 printer I often manually adjust the feedrate to 200 using the dial on the printer, however in Octoprint this change is never updated or reflected and it remains at 100% even though it is actually at 200%. Along these lines, if the feeding rate is 200% on my printer physically, shouldn't the flow rate also be 200%, and shouldn't this also show up in the octoprint GUI?
If this is not a bug, how could this his functionality feasibly be added from a development standpoint?
It can’t, because there is no (gcode-)command to query the feedrate setting from the printer.
Marlin seems to report feedrate (if compiled in):
Set feedrate to 80%
Back up current feedrate
And this is the output on my printer:
Send: N20279 M220*45
Yes, but not every firmware implementation has it enabled.
It could be checked on startup or an option in the printer configuration. Would be really nice to have it.
For not everyone is in use of this, it may be a plugin project
Checked Reprap firmware:
Speed factor: 100.0%
So it should be usable on most of the printers out there.
At least we should change the comment on the UI, as it has proven wrong:
Die Feedrate kann nur gesetzt werden, sie kann nicht von der Firmware zurück gelesen werden. Dies ist eine Beschränkung im Kommunikationsprotokoll. Es gibt keine Möglichkeit, den aktuellen Wert anzuzeigen.
Feedrate reporting was added in Marlin 2.0.5, without a way to check if it is there or not (other than just trying); there is no "firmware capability" that reports if this feature is available. OctoPrint would have to "poll" periodically to see if the feedrate has changed, on the off-chance that the user has changed the feedrate on the printer LCD. This would lead to communication overhead that may not be worth the hassle.
Hmm, I think octoprint does ask parameters anyway periodicaly.
The check for the feature could be done on connection.
Maybe it wouldn't be worth the hassle for you, as you don't seem to need this feature. But the comment on the UI and the comments in this forum show, that I wouldn't be the only one to appreciate this feature.
We prefer autoreporting stuff, some people already have stuttering and bandwidth issues so we don't want to make things worse. The obvious comment in the UI also made people go and contribute the missing features, so autoreporting fan speed I know is definitely a (disabled by default) option.
There's nothing stopping you from writing a plugin to do this - the documentation is quite solid and there's a strong community of plugin authors to help you out (especially on Discord) in case you get stuck.