Single_Arduino - Extruder heater voltage

Howdy,

First off, if this is covered somewhere, please point me to it.

I am playing with the latest SVN version of the Arduino firmware; I'm using the RepRap Host Extruder Exerciser. Is 3.6 volts what I should be expecting in terms of the what the heater is provided...

Poking around in the firmware, it seems that the heater can be set to high/low/off (var heater_high) - but the Extruder Exerciser only has a checkbox for on or off (active).

Is the Extruder Exerciser screen the logical place to be testing out extruder, temp sensors, ABS vs HDPE, nozzels sizes, etc? Is it logical to suggest that this screen give more control over the heater temperature beyond just on/off (active)?

Thanks.

Edited 2 time(s). Last edit at 12/29/2007 09:01AM by RoundSparrow.

Hey,

1. the extruder firmware stuff on Arduino is totally untested right now. I did a whole bunch of work on it but it should theoretically work... the temp conversions seemed good to me.

2. I'm not entirely sure what you mean by 'what the heater is provided'. where did you get 3.6 volts from?

3. i'm not 100% sure how the extruder exerciser sends the temps. the set heater SNAP command has a high/low heater setting and and the 2 temp ranges. it may not be setting it exactly like the host does during actual printing. it should though.

4. its definitely the right place to test your extruder. its not entirely clear how it works, but basically you enter the desired temperature, hit enter, and then click the 'heater active' checkbox. that tells the exerciser to actually turn the heater on/off which will start the heating process and will give you temperature readouts. once you get it to the proper temperature you can turn the extruder speed up to get actual extrusion.

cheers!

ps. i'm sort of jealous that you get to try out the new extruder code before i can. when i get back, i'll give it a thorough testing and then i'll be making a v1.1 release of the arduino code when its totally working. also, make sure your prefs contain the same values as defined in extruder_snap_v0.h that will make the temp conversions accurate

ZachHoeken Wrote:
-------------------------------------------------------
> Hey,
>
> 1. the extruder firmware stuff on Arduino is
> totally untested right now. I did a whole bunch
> of work on it but it should theoretically work...
> the temp conversions seemed good to me.

4 of us played with it at the Houston meeting today It seems to work, but I think I had some ABS partially unmelted stuck in my extruder that was holding us up (plus we were jumping around topics and random visitors at the Pizza place were asking us about RepRap!)


> 2. I'm not entirely sure what you mean by 'what
> the heater is provided'. where did you get 3.6
> volts from?


By putting a multimeter directly on the screw terminals supplying the heater. We measured 3.8 volts today, so I've seen 3.6 & 3.8. The LED doesn't seem that bright to me. Again, we are talking on the screw terminals of the board feeding the Nichrome coil.



> 3. i'm not 100% sure how the extruder exerciser
> sends the temps. the set heater SNAP command has
> a high/low heater setting and and the 2 temp
> ranges. it may not be setting it exactly like the
> host does during actual printing. it should
> though.


In theory should we be seeing the voltage change on the Nichrome screw terminals or the LED change?


> ps. i'm sort of jealous that you get to try out
> the new extruder code before i can. when i get
> back, i'll give it a thorough testing and then
> i'll be making a v1.1 release of the arduino code
> when its totally working. also, make sure your
> prefs contain the same values as defined in
> extruder_snap_v0.h that will make the temp
> conversions accurate


Ok, I was using stock RepRap host prefs I need to replace my Thermistor, I think having it on the extruder tip ruined the wires from the dozen times I've had to remove it to unclog...

// Stephen Gutknecht
// Canyon Lake, TX

Edited 3 time(s). Last edit at 12/30/2007 09:30PM by RoundSparrow.

hmm... the voltages are very bizarre, although there is probably an easy explanation. the TIP120 transistors drop about 1-2 volts from the source voltage. my gut feeling is that you're feeding it 5v.

seems very likely that either:

a) the power socket was soldered in backwards.
b) the power socket is backwards on the board itself. i doubt this is the case, but i wont be able to find out until i get back

there are two notches on the molex power connector. do they match up with the marks on the silkcreen or are they flipped 180?

[www.reprap.org]