Another Stratasys uPrint retrofit
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@Pete_A said in Another Stratasys uPrint retrofit
My understanding of the stepper power amplifier block is that it functions basically like one side of an H-Bridge but it provides current limiting for each winding. It still takes step/direction inputs. I have a link someplace where the question was asked and explained. It is an unusual implementation of the driver chip, but it does work. As mentioned above, it doesn't work with the TMC drivers on the Duet so I bypassed the whole lot.
Yes! I was totally used to using drivers that controlled both sides of the H-Bridge simultaneously. To come across this weird DC motor controller being split into two phases really threw me through a loop. You are correct that you can essentially hook up a Step / Dir signal, but to be super effective it should be a PWM signal that can micorstep.
That person that asked the question was me! https://electronics.stackexchange.com/questions/398928/interfacing-with-two-full-bridge-pwm-motor-drivers-to-control-a-stepper-motor
Check out the page I started writing about the uPrint here: https://wiki.cnc.xyz/Stratasys_uPrint_Retrofit
It outlines how to operate the on-board steppers, servo and reading things like thermocouples. Unfortunately right now it's all just theoretical. I'm waiting for my new PCB adapter boards to arrive next week. I'm feeling pretty good about it though. In theory I will have every function controlled by the Duet (except for the Material Bay) by the end of next week.
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I'm trying to post a useful reply but the stupid akismet spam filter keeps blocking me for some reason
Small world :). The provided explanation was really helpful. When I first saw the circuit diagram and design constraints I just knew it was for a uPrint.
Pins arrived today for my extruder splice loom. No connectors though
Had a quick look through the wiki page; nice and concise. Would have saved me a bunch of work
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@Pete_A said in Another Stratasys uPrint retrofit:
stupid akismet spam filter keeps blocking me
usually works if trying again a little later
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@drphil3d said in Another Stratasys uPrint retrofit:
One thing I should make sure you know. Do not use the +5V ref to supply 5 volts anywhere. That is a steady voltage reference for the thermocouples. It is not capable of supplying very much more than a few mA. Use the +5V testpoint instead (lower down on this photo).
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@aj-quick there is a fork of paneldue with landscape display and support for a knob encoder by diabase. You could look at that.
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@drphil3d i have a 768 sst and am interested in what you have going here do you think a full rebuild would not be best?
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@rexx said in Another Stratasys uPrint retrofit:
768 sst
I would say try to keep as much of it together as possible. I have been working with a more recent duet 2 wifi + Duex5 and the latest RRF 3 to take control of a Uprint SE+. The newer duets allow 5V in on the endstop inputs. The Duex5 allows for 5V logic to control the different switches and SSR on the PDB. I have gained control of everything even the dc servo motor using a Geckodrive G320x. I imagine with the 768 sst you would just need 2 G320x external drivers. I interfaced it with the CONN_LCD step dir outputs. Since there are two there, you shouldn't run into any issues. I have the Duex5 for the PWM outputs for controlling the heaters, power enable, and some logic signaling and thermistor inputs for directly reading the thermcouple 10 mv/C output from the J13 or J15 connector. To calibrate the temperature range you will need to use a voltage divider to take the 5V signal scaled down to 3.3V. Auto PID tuning worked great. I have even been able to gain control of the material bay with some soldering of wires. Still working on configuring the right pinouts to control the material bay. I'm having an issue with the fan outputs as GPIOs. I may have to find other pins, yet am quickly running out of enough pins to control everything. 5V and Vin both read in on the fans, yet the PWM pins max out at 0.5 V. I can set it to 0 and get 0V, yet it won't give me the full 5V or 24V Vin output. Not sure if I am already pulling too much from the 5V regulator or if I may have accidentally blown all of the fan mosfets. Not sure when that would have happened. I am still working on getting things calibrated and all the safety outputs run into the duet, yet once I do I'll be sure to post the whole setup here on the forum.
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@archeantus Very interested to see what you have accomplished!
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@aj-quick I am entering what I have done with the help of the wiring diagrams you posted on your website to the Hackaday.io Hack It Back competition.
Feel free to see what I have been doing and videos of the functioning Uprint SE+ fully controlled by the Duet 2 WIFI with DueX5 expansion board and Geckodrive G320X servo motor controller.
The link is here: https://hackaday.io/project/186419
I will be uploading the Duet configuration files and macros plus more information on the wiring in the coming days. I still have some more work to do to get it to run flawlessly, yet both extruders work and the chamber heater works with reasonable PID profiles.
I have printed ABS and PLA, yet haven't figured out the best chamber temps for the PLA to cool properly. Right now I can use either the Stratasys ABS in the spool under the printer or my Hatchbox ABS from a spool behind the printer. Both print wonderfully. The video is using the Hatchbox PLA red filament.
I will likely be adding an air filter to help with the ABS fumes as well as a PanelDue 5i for convenience when using the printer.
Please let me know what you think!
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@archeantus Absolutely impressive!
I would like to know how you have controlled the stepper motors directly from the Duet though the PDB. As I remember it, the onboard drivers take a PWM sine signal for control instead of regular step signals. Did you work out another way to do it using the Duet drivers directly!?
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@aj-quick I run the motors directly from the Duet.
Hey, I wouldn't have been able to get where I did without your work. Would you like to be added as a contributor to the project?
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@archeantus the extruder is controlled from the step and dir pins sent to the Geckodrive G320X. I feed the output from the Geckodrive through the PDB. During the tool change I switch the motor driver direction to make it always extruder the right way depending on which tool is being used.
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@archeantus said in Another Stratasys uPrint retrofit:
Hey, I wouldn't have been able to get where I did without your work. Would you like to be added as a contributor to the project?
I've got a Hackaday account now, not sure what that entails: https://hackaday.io/ajquick
@archeantus said in Another Stratasys uPrint retrofit:
@aj-quick I run the motors directly from the Duet.
Would you be able to explain more? Mainly just what connections on the Duet are made to the PDB for the motor control? From the drivers directly? Any bypassing of the drivers on the PDB already?
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@aj-quick The X, Y, and Z motors have wires extended using the female Molex connector you referenced in your webpage for the I/O board on one end and the Duet connectors on the other. I crimped some wires and fed them through the electronics box to the Duet. This is like what @drphil3d did to control the movement motors.
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@aj-quick So I completely bypassed the PDB for the xyz motors as the TMC drivers on the Duet 2 are strong enough to drive them directly and quietly too.
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@aj-quick The extruder motor I connected using the J13 pins (31, 33, 35, and 37) the pwm outputs and the encoder signals on the Geckodrive. I just followed the recommended settings for the Geckodrive and it works ok. I used the stp 10 and dir 10 outputs from the CONN_LCD connection to control the external motor driver (Geckodrive). Everything is powered either from the 24V or 5V output of the existing power supplies to run the Duet 2, DueX5 and Geckodrive. The 5V is to ensure enough current for the pwm signaling for the heater control and PDB Power Enable and Motor Enable which uses up all 5 PWM outputs of the DueX5. I read in the thermocouple temps to the thermistor inputs using a voltage divider to bring the signal down to roughly 3.3V scale which enabled the temperatures to reach the correct temperature ranges. This was for the Duet as it seemed to work based on 3.3v though it can in theory handle 5 V. I did have to adjust the linear ranges as you mentioned in one of your posts. I used the touch points to calibrate at two points (finger temp and 100C) then once that was close I went to 200 and then 300 to make sure I didn't burn anything up. Once I got the ranges correct I ran the auto calibration and it now handles the temp changes quickly and accurately. With the DueX5 the 5V endstop voltages can be sent directly to the endstop pins on the Duet without having to do any level shifting to 3.3V.
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@aj-quick Hackaday says you need to accept the terms of the contest. Did you get an invite to the project?
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@archeantus Ahh that all makes sense. My first test was to do something similar. I had a Geckodrive G320 installed, several AC relays and made direct connections to the motors. I only abandoned that idea after I found one of the 120VDC power supplies was located directly on the PDB.
Using both seems to be the easiest solution.
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@aj-quick Yeah, it was pretty straight forward after all you guys have done! It works amazing!
I just couldn't gut the extruder with the whole tilt mechanism and CNC parts.
The extruders are insane! I can't out run the extruder. I end up with vibrations in the print before I can max out the amount of hot filament! It is just crazy! I'll see if I can get a video later showing this. I think I end up maxing out the travel speed of the Duet.
I ended up adding an accelerometer to help me know how to minimize ringing in the printer using input shaping. It seems to have helped a lot! Maybe it will help with the vibrations are high print speeds.
