Anybody wants a stepper motor analyzer?

nyaru

@zapta
thanks for the nice report

@zapta said in Anybody wants a stepper motor analyzer?:

The CC6920BSO seems to have much higher output impedance, when I loaded it with 100ohms to ground Vout went down significantly while the TI didn't change.

I checked the datasheet and it shows "Output resistance load": probably output impedance, is 1.5k ohms.

Does this mean that the following should be considered in such a case?

MPU needs high input impedance than sensor
It is better not to use an electrical LPF filter

zapta

@nyaru, I calibrated the sensors with DC current from a power supply, using the current reading on the NRF52 microcontroller. With the TI TMCS1108A4BQDT I am getting 400mv/A, with the CC6920BSO 5A I am getting only 280 mv/A, presumeably because of the loading by the MCU's analog input.

You may want to do the same with the RPI PIco, I don't know how its' compares to the NRF52.

JoergS5

@zapta said in Anybody wants a stepper motor analyzer?:

CC6920BSO

according to datasheet https://datasheet.lcsc.com/lcsc/2108201830_Cross-chip-CC6920BSO-20A_C2880432.pdf page 4 it is about 270 mV/A.

zapta

@joergs5 , yes you are right. That's good news because it's not impedance sensitive as I thought. Also makes sense since +/-5A at 400mv/a will require 4V span on a 3.3v IC.

The PCB has room for optional config resistors R4, R5. Can be used to select the range base on the IC installed.

https://github.com/zapta/simple_stepper_motor_analyzer/blob/main/kicad/stepper_analyzer.pdf

https://github.com/zapta/simple_stepper_motor_analyzer/blob/main/platformio/src/misc/hardware_config.cpp#L53

ctilley79

@zapta I'm dying to get one of these. Are you still producing batches? EU only or US as well?

zapta

@ctilley79, I don' t produce them any more but other here do.

I am working now on a different version that uses a computer to show the data using a bluetooth link. So far it's promising. Here is a video with a screen shot.

https://github.com/zapta/ble_stepper_monitor/blob/main/docs/screen_capture_video.mp4?raw=true

zapta

Here is an interesting observation that I recorded today on the A stepper while my V2.4 was printing.

While resting, the stepper current is reduced from 1.4A to 1A. This is before the standby stepper current that is even lower, and it protects the driver when the peak coil current may become also the RMS current. IIRC there is a default setting for it.

(Open for full resolution)

Th0mpy

Sorry to revive an older thread. I finally got my stuff together and posted what I have left of the OG stepper motor analyzers on Etsy. If you're still interested in the original version have a look: https://www.etsy.com/tArrayEngineering/listing/1359496786/stepper-motor-analyzer

mesacrash

I would like one of these.

Th0mpy

@mesacrash I have the original version in my etsy shop (linked above). You can order them right from there.

rjenkinsgb

Hi all,

I've assembled another unit from the original parts I got, but I am having serious problems trying to build the program for it..

I've changed machines since I did the original so its a fresh install of VS Code & platformio etc.

I cannot get the Wizio stuff to work; it looks like some part of that project has been either removed or renamed?

I never normally use Visual Studio & the only experience I've had with platformio was in one day, for the last one of these I built.

Any clues or fixes to get it to build properly would be greatly appreciated!

Working on Win 10 64, with all updates etc.

(I normally program such as PICs using MPLab & CCS compiler, or industrial controls - never visual studio stuff).

zapta

@rjenkinsgb, IIRC, @Th0mpy mentioned that he encountered a change in Wizio's repository (some stuff was moved or deleted) and he fixed it somehow. Hopefully he will chime in here. If it will not resolve, please let me know.

rjenkinsgb

@zapta
Hi,
OK, thanks for that, hopefully Th0mpy is around!

I can't find anything relevant in his posts in this topic, unfortunately.

Th0mpy

@rjenkinsgb Yeah I'm around

I will need to double check but I do have a repo which does work. Give me the morning to look it over and I'll link it here.

rjenkinsgb

@Th0mpy
Excellent, thank you

Th0mpy

@rjenkinsgb

You can update your code to point to these two repositories:
https://github.com/th0mpy/wizio-pico
and
https://github.com/th0mpy/framework-wizio-pico

As I recall, that's all I had to do. Let me know if that works and I can double check my DEV VM when I get home later.

rjenkinsgb

@Th0mpy said in Anybody wants a stepper motor analyzer?:

You can update your code to point to these two repositories:

That's got it working, thank you!

Anybody wants a stepper motor analyzer?

Robert J.

Robert J.

Robert J.

Robert J.