Implement M309 Feedforward for remote heaters

[Kiolia]

Hello, I've been trying to get M309 working on my Delta (6HC with 3HC controlling E and T0), but I could not see any difference in heater PWM behavior with feedforward enabled or disabled.

I inquired on Discord and gloomyandy stated that RemoteHeater.h currently says feedforward is not supported on remote heaters "yet" (in the SetExtrusionFeedForward declaration). However, this is not listed as a known limitation for CANboards in the online docs. I wonder if this just fell off the radar?

Could this be added as a known issue and ideally slated for fixing in a future release? It seems like a significant gap to have unsupported heater control functionality for such a common hardware case.

[droftarts]

@Kiolia I've added this as a feature request on Github:
https://github.com/Duet3D/RepRapFirmware/issues/1030

Ian

droftarts created this issue in Duet3D/RepRapFirmware

open [FeatureRequest] Add support for M309 Heater Feedforward to expansion and tool boards #1030

[Kiolia]

@droftarts Awesome! Thanks much!