Anybody wants a stepper motor analyzer?
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@zapta said in Anybody wants a stepper motor analyzer?:
A couple of notes:
- Theoretically the analyzer needs only 4 wires to measure the currents of the two coils. You can build a harness that has only 4 wires with Y splitting on both ends.
- For double sided tape for the TFT, I had good experience with this kind of thermal tapes. They hold well and designed to be isolating. https://www.amazon.com/gp/product/B072JJD2ND . I also use them between the Pico and the PCB for extra isolation.
- You mention residual current (0.04A in the picture). I presume that you set the zero in the Settings screen.
I realise only two through connections are monitored, but the harness needs two connectors at either end anyway..
To fix the display, I put a few strips of kapton on the back & over the rear of the motor connectors to ensure good insulation, then some generic thin double sided tape to hold things together.
Yes, it has been zero'd - the readings fluctuate randomly +/- a small amount with no connections. When I first turned the unit on, it read somewhere around 300 - 400mA on each channel.
It's a really nice design, the options and screen responsiveness are great. Playing around with it, I realised it can do for something else I have been intending to make for some time - an encoder tester for machine tool systems.
If I add a pair of analog differential inputs with selectable gain in place of the current sensors on one, it can monitor either sine or digital encoders & linear scale signals - pretty much just change the Amps indication for Volts!
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@zapta said in Anybody wants a stepper motor analyzer?:
A question for the people that uses various current sensors, how do tell the firmware what is the mv/A sensitivity of the sensor you use?
If you get some TMCS1101A4BQDT ICs, they are the same sensitivity as the original ones.
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@rjenkinsgb said in Anybody wants a stepper motor analyzer?:
TMCS1101A4BQDT
The datasheet of the TMCS1101A4BQDT suggests that it requires 5V supply. Does it work well with 3.3V?
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@zapta It seems that either 3.3v or 5v work just fine. The limits are just a little different.
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@th0mpy said in Anybody wants a stepper motor analyzer?:
@zapta It seems that either 3.3v or 5v work just fine. The limits are just a little different.
Good to know. Thanks. Yes, 3.3 will cause saturation for +/-5.75A @400mv/A but we don't need that full range, and it is specified for 3.3V for the other ranges.
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So that the prototype housing of the AWD Stepper Motor Analyzer fits quite well, just adjust a few small things.
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@dogma2k said in Anybody wants a stepper motor analyzer?:
AWD Stepper Motor Analyze
Wow! That's a nice design.
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Hey everyone, I have a new batch of sensors being delivered early next week. If you're interested hit me up via chat.
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The final case is finally ready. I also installed a FlowMeter. Everything fits in and the lid even closes.
If you like, you can download the STEP file
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@dogma2k , looks very impressive. If you can, please post here a picture with all screen on, it will be even more cool.
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@zapta
Unfortunately only provisionally because I don't have my 5V transformer an Arduino Uno yet
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@zapta
Can the analyzer be switched on and off during operation? Because you can / should only disconnect the motors without electrical voltage. Or does it matter here because the input and output always have continuity and the measurements are only picked up in parallel? -
@dogma2k, the electronics and the stepper circuit are isolated from each other so it's safe to turn 5V power on/off even when the printer is working. It will not damage the electronic and the print will continue with no interruption.
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The analyzer is finally running after I had to remove the display again because the soldering points of the connector had pushed through the metal frame of the display and always caused a short circuit
Thanks for the nice toy
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@dogma2k said in Anybody wants a stepper motor analyzer?:
the soldering points of the connector had pushed through the metal frame of the display and always caused a short circuit
Wow! Looks awesome. I am glad that this didn't cause a permanent damage. I maintain the insulation by
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Using an insulated 10mm width double tape on the back of the PCB, at the marked areas. E.g. https://www.amazon.com/Adhesive-10mmx25mx0-25mm-Thermally-Conductive-Computer/dp/B075FRPXQ5 . I also apply it between the PCB and the PICO, just in case.
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Pre cutting the servo connectors pins such that they don't protrude at the back of the connector. This is the trimming jig I use https://github.com/zapta/simple_stepper_motor_analyzer/blob/main/3d/connector_trim_jig.stl
BTW, it should be ok to connect multiple analyzers to the same servo since the sensors serial resistance is very low.
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@dogma2k, the current readings seem have have offset. You may want to reset it in the Settings screen with the motor disconnected (that is, zero current).
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@zapta said in Anybody wants a stepper motor analyzer?:
- Using an insulated 10mm width double tape on the back of the PCB, at the marked areas. E.g. https://www.amazon.com/Adhesive-10mmx25mx0-25mm-Thermally-Conductive-Computer/dp/B075FRPXQ5 . I also apply it between the PCB and the PICO, just in case.
I had double-sided tape in between. Wasn't enough
https://www.amazon.de/gp/product/B08YJK6L1T/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1
It didn't matter, it went well, it was just fun to find the fault ...- Pre cutting the servo connectors pins such that they don't protrude at the back of the connector. This is the trimming jig I use https://github.com/zapta/simple_stepper_motor_analyzer/blob/main/3d/connector_trim_jig.stl
That would probably have been the best had I done that
BTW, it should be ok to connect multiple analyzers to the same servo since the sensors serial resistance is very low.
Even more? I already need 4 pieces because I have 2x X steppers and 2x Y steppers.
The small OLED is also not yet in operation for the filament flow meter, because I haven't had time to get the Arduino UNO readyI still have a problem that as soon as the motors are working, the display does not react at all or almost not at all.
If the motors are switched off with M84 then you can use the display properly.
How come that -
@dogma2k said in Anybody wants a stepper motor analyzer?:
I still have a problem that as soon as the motors are working, the display does not react at all or almost not at all
Can you explain what what you mean? Chan you change pages? Do you see any reading on the main page?
Per my previous post, it seems that your sensors need zero calibration. This is done in the Settings page (accessible from the main page) with the motor disconnected.
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@zapta said in Anybody wants a stepper motor analyzer?:
@dogma2k said in Anybody wants a stepper motor analyzer?:
I still have a problem that as soon as the motors are working, the display does not react at all or almost not at all
Can you explain what what you mean? Chan you change pages?
Would you have to recognize property in the two videos what I mean (if not, I'll make better ones)
If no stepper has been used, I can switch through the menus, as soon as the stepper has moved once, the displays can no longer be operated.I'll do the zeroing with disconnected stepper afterwards when I'm back.
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@dogma2k I had this issue on my first analyzer I boiled it down to a couple things.
As @zapta mentions, if you don't cut the pins there may just enough bite into the back of the LCD which shorts things out. I pulled the connectors out, recut, and used some 3M VHB to secure the LCDs.
Finally, double check the castellated pins on the PICO and make sure they're solid. If you used a thicker adhesive behind the PICO it might prevent good connections.
