The FAULT output that drives LOW whenever the H-bridge FETs are disabled as the result of over-current protection or thermal shutdown. The device remains disabled until either nRESET pin is applied, or VM is removed and reapplied.


It's unlikely a thermal issue because there is a huge heat sink on them. I measure the fault pins for each. The one that keeps on running is 0.25 V (which I don't get). The one that's not moving is about zero. This makes sense.

I've assembled four PCBs. The first one works flawlessly. The other three all have the same issue with one motor stopping (fault pin triggered).

Datasheet: https://www.ti.com/lit/ds/symlink/drv8825.pdf

 

Actually, both fault pins are LOW. I don't understand how one motor is still moving.

I'm using this ESP32: https://www.mouser.com/ProductDetai...2-DevKitC-32D?qs=%2BEew9%2B0nqrDsObWEpDx6YQ==

I can provide schematics and programs. When the motors are running a program with linear motion, it works fine. Whenever a program is run with variable motion, one stepper motor stops. I turn the power off.

When the power is turned on again, both motors run a little. Then one motor stops. I repeat this and the same thing happens.

 

One motor might be stopping because of the regulator. So I'm going to try MIC29310-5.0WT (instead of the VXO7805-1000).

The LDO has a 3 A output current (instead of 1 A).


* stepper motor datasheet says 1.7 A
* stepper motor driver rated for up to 2.2 A per coil

Since stepper motors have two coils, the total current required for one stepper motor is 2 * 1.7 A = 3.4 A.

Now, you have two stepper motor drivers, so the total current required for both motors is 2 * 3.4 A = 6.8 A.

Since your DC-DC converter is rated for 1 A, it does not provide enough current to run both motors with their respective drivers.

To power these components properly, you need a DC power supply that can provide at least 6.8 A of current to handle the total current requirements of the two stepper motors and their drivers.

 

Sounds like you are on the right path. I'll add that the DRV2209 is a vast improvement over DRV8825 and when I upgraded, all my issues went away. I don't think upgrading would solve the issue you have currently, but if you have other troubles, this should be first in your list of remedies.

 

DRV2209

I think you mean TMC2209.

 

I think you mean TMC2209.

Yes, thank you for the correction.