@Nxt-1 Wow! looks great. I'm surprised the stepper motor can handled all of that equipment on the one axis.
Just one question: Why not have the radiator and pump outside? Then you could close up the sides and retain more heat for warp-prone plastics.
@OBELIKS said in Pressure Advance Calibration:
@Munce31 If you are using the script @jens55 posted, you can add
print("M117 %.3f" % pressure_advance)after
print("M572 D0 S%.3f" % pressure_advance)
Hi @OBELIKS thanks for providing that. It'll make it easier to watch the test print and see what pressure advance it current is running at.
@wilriker said in Pressure Advance Calibration:
@Munce31 You could manually add
M117 <current PA value>into the GCode file after every change of PA.
Yeah I figured I could do that as well, but that potentially could be quite laborious. I was thinking more along the lines of something like M117 <current PA value> being added directly into the python script so that it can be automated.
Hi All
I've been using this python script to fine tune my pressure advance on my zesty nimble extruder. It has been a massive help in this process.
Just one suggestion - I don't know if it is possible - however, I would like to see what pressure advance setting it is currently at during the print. Preferably to be displayed like a pop, similar to how the Report PA macro works in https://forum.duet3d.com/topic/6181/tuning-macros-menus-accel-jerk-retraction-pressure-advance. Is it possible to add something to this python script to report current pressure advance? It would make fine tuning the pressure advance just a little easier by taking a chunk of the guess work out of it.
Thanks,
Vince
This delta looks awesome!
Is there any chance you'll be making the design available for others to create their own?
@droftarts said in Flashing firmware on Mac OS X:
Thank you so much for this. Saved me a massive headache trying to flash my paneldue v3.0 5".
@Quadcells very keen to see how this goes. Please let us know. Thanks.
Also, I'm wondering if there is a way to make the 4th tower move simply as an offset of the Z height?
My understanding is that the current coding in RRF is for flying extruders, so it tries to maintain 'X' amount of distance between the extruder output and the hot end's entry point, effectively the length of the bowden tube.
The scenario I'm thinking of is for cameras, where you want the field fo view to remain at the same level or offset of where the print head currently is in the Z orientation.
Wow that looks like a fantastic piece of engineering. I guess you're printing in a heated chamber environment.
I see that your tower is driven by belt, so how do you prevent it from falling down with all of that weight on it?
Also, am I right in saying that you can have the 4th tower's end stop lower than the end stops of the delta towers?
@Nxt-1 said in Delta 4th axis length and limits?:
@danal said in Delta 4th axis length and limits?:
Following with great interest.
I can already tell you that the first version I designed of the 4th axis worked quite well. The arm was printed to heavy and the carriage I used wasn't ideal but it did it's job.
Thanks to this thread i'm very keen on having this on my heavily modified Anycubic Predator.
You mentioned that the first version worked quite well. Have you had any other revisions since?
What challenges did you encounter when designing and implementing the fourth tower?
Got a video of it in action?
In my case, I'm running a zesty nimble remote drive extruder. I'm planning on using a shorter drive cable and have the extruder motor, some-what in the middle, with a gimbal to minimise forces that the cable would exert on the effector. Also, I'll add the berd-air pump to the forth tower to reduce the length of the air tube and reduce the pressure drop that a longer air tube would induce. Perhaps also add the filament spool to the other side to reduce the length of filament to the hot-end. All just ideas at the moment. Will be interesting to see how it turns out in practice.
Anyway, I'm interested in hearing your thoughts.
Thanks,
@dc42 Thanks for confirming that using a spare heater port is a better option for an air pump.
Yes, I will be installing a flyback diode.
However, would it be beneficial if I use two? One screwed in at the heater port terminals to be closer to the mosfet, and another at the motor to reduce any interference created by the PWM?
Also, will the heater port pwm up to 25khz, as recommended in other threads?
Weighing up my options I think the most effective option is to remap a heater to a fan port. I'll investigate this further. Thanks for your help!
@EasyTarget said in 24V air/vacuum pump questions pertaining to inrush current:
That's the spirit! I had a small point, I guess the pump runs continuously? if it is stop/starting make sure there is enough time between cycles for the NTC's to cool down. They are not suitable for bang-bang type controllers.
Yes the pump will be run as part of a berd-air-like system, so mostly will be on and not switched on and off.
@EasyTarget According to the data sheet of the air pump, the unloaded current is equal to or less than 450mAh, so i'd expect more when loaded.
Unfortunately the details on the thermistor are thin, however it is mentioned in the specifications that the DC current rating is 200mAh. I'm assuming that is maximum.
So if I use three in parallel that would bring total resistance down to 33ohm and total current capacity to 600mAh, which might be close to loaded current draw of the pump.
I guess there's no harm in trying it out I guess.
https://www.jaycar.com.au/100-epoxy-dip-ntc-thermistor/p/RN3432
Actually I have another thought for the thermistors.
Could I use 5 of 100 ohm thermistors in parallel?
This should theoretically bring the resistance down to 20 ohm. 20ohm should reduce the maximum current down to 1.2 amp?
Does the math check out?
Why those thermistors, you may ask. Well because they're readily available at the local electronics show in Australia, whereas the shipping price from Mouser or Element14 far outweighs the cost of an appropriately sized thermistor.
@Dougal1957 Sorry i probably didn't word my previous question clearly. I mean to put two diodes in parallel to prevent back EMF. May be overkill?
So if the Fan mosfets are actually recommended to not exceed 1.5 amps, does that mean the minimum resistance for the thermistor should be:
24v / 1.5 = 16 Ohm?
@EasyTarget said in 24V air/vacuum pump questions pertaining to inrush current:
I think the 1N4007 flyback would be fine; it has a 30A forward surge capacity according to this datasheet, 1A is it's continuous rating. Similarly the Mosfet probably has a surge rating too.
For the inrush surge, a correctly rated NTC might help, even if the current is within the overall capacity of the mosfet/system you might get a vin drop which could cause issues. Also I'm not as expert as others here but I think there is an inductive resistance/load to consider too which may either increase or reduce the surge. I just don't know DC motors well enough to say.
But I do know from experience that the inrush surge on my CNC's spindle could brownout it's mega256 based controller on occasion, until I beefed up the supply.
Ahh thanks for clearing that. My concern with the diode was that its was smaller than the inrush current and may overload it. Good to know that it's appropriately sized when it comes to burst current.
I wonder, could i put two diodes in parallel to share the current load and flyback?
Hello
I have a couple of questions with regards to aspects of directly wiring a 24 volt vacuum pump to the duet wifi.
To assist my queries I have the following:
Duet wifi version 1.03 -- I understand that this already has a flyback diode installed.
The following vacuum pump vacuum pump in 24v:
1N4007 1000v 1A diode for flyback
Firstly, I have measured the resistance of the motor of the vacuum pump, turning the shaft at each step and the lowest resistance measured was 13.8 ohm (I removed the vacuum pump assembly so that I could properly turn the shaft of the motor with my finger). With 24 volt, and to be conservative with the resistance let us round down to 13 ohm, then theoretical maximum inrush current would be 1.9 amps.
Is it necessary to run in series with the motor an NTC thermistor? From my understanding 1.9 amps is well within the maximum amperate capability of the fan mosfet, which from what I've read is 3 amps.
Would I be right in saying that the 33ohm thermistor is only required with 12v motors where the resistance can be less than 8 ohm, therefore exceeding the 3 amp maximum for the fan mosfet?
Secondly, I currently have at my disposal a 1N4007 diode which is rated to 1 amp, for use as a flyback diode at the motor.
Would it be more suitable if I used a diode such as a 1N5408 which is rated to 3 amp? I understand that the Duet 1.03 has the flyback diode already installed, but from what I've read, it wouldn't hurt to install another to protect against PWM.
Perhaps I would be better if I ran an external mosfet, however I'm unsure if they could take PWM frequencies up till 25khz?
Hope I'm clear with what I'm trying to convey.
Thanks in advance