I want a thermally activated Fan

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dc42
I looked into using the second controlled fan connector on the Duet 0.8.5 as a thermally-activated hot end fan, however I didn't implement it because of safety concerns. It is very important that after a reset, the fan turns on...

@dc42, thanks for taking a look at this. I see why the HE fan needs to come on at reset to prevent blocking in the hot end but I don't really understand the safety concerns. Anyway, if I still think I need it, maybe I'll branch the firmware myself.

best regards

Was searching to see if the Duet supported a thermally activated fan and found this thread. I am wanting to activate some fans if the temp in the base of the printer exceeds a defined value. I was planning on using the E1 thermistor connector for the temperature detection and one of the two fan PWM connections. It sounds like this isn't in the firmware at this time. Is this a type of features others would be interested in? I would imagine a special M code to enable it. Something like:

Mxxx E1 S50 F1 <- When the thermistor on E1 is above S50, turn on F1 (or however the fan is referenced).

Maybe even allow a second temp to be defined and the fan speed increases as it get closer to the upper limit. The function could be disabled with a command like:

Mxxx E1 S0 <- Disable auto fan.

There are thermo-controlled fans for PCs available. They are not off but at low temperatures they only run slowly and you cannot hear them. Would not this be an alternative? They are available with different speeds. Also there are circuits (schematics and pre-built) where you can set the speed/ trigger temperature.

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Slicer: Simplify3D 4.0; sometimes CraftWare 1.14 or Cura 2.7
Delta with Duet-WiFi, FW: 1.20.1RC2; mini-sensor board by dc42 for auto-leveling
Ormerod common modifications: Mini-sensor board by dc42, aluminum X-arm, 0.4 mm nozzle E3D like, 2nd fan, Z stepper nut M5 x 15, Herringbone gears, Z-axis bearing at top, spring loaded extruder with pneumatic fitting, Y belt axis tensioner
Ormerod 2: FW: 1.19-dc42 on Duet-WiFi. own build, modifications: GT2-belts, silicone heat-bed, different motors and so on. Printed parts: bed support, (PSU holder) and Y-feet.
Ormerod 1: FW: 1.15c-dc42 on 1k Duet-Board. Modifications: Aluminium bed-support, (nearly) all parts reprinted in PLA/ ABS, and so on.

Yes, I could use something like that. I just wanted to take advantage of the extra fan controls on the Duet. A thermistor and a fan is a lot cheaper than the all-in-one temperature controlled fan. Besides, I already have the fans and thermistor.

Edited 1 time(s). Last edit at 10/30/2015 11:21PM by ElmoC.

I will be taking another look at implementing this in my next firmware release.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
dc42
I will be taking another look at implementing this in my next firmware release.

Thanks. That would be really helpful.