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Topic: [SOLVED] Can't use DRV8825/A4899/L298N for my stepper motor (Read 367 times) previous topic - next topic

Lothean

Hello everyone!

I recently got a scanner (Epson Perfection 1200U) with a bipolar stepper motor that does not have any useful info on it. The only info I have is the coil resistance that I mesured (5.8 Ohm) but that never helped me.
The problem that I have is that I must use this precise stepper motor/scanner assembly.
I tried the DRV 8825 and the A4899, but these boards were not working at all with this particular motor (tried the same setup with another motor and it was working), it was not even holding the motor in place: nothing, no matter the current!
So I then tried the L298N, but it gets very, VERY hot, and so does my motor above 9V.
I also tried to run it at its bare minimum voltage with camcorders PSU's (8.4V) and the bridge was still too hot and the motor missed some steps and did some weird noises.
So I really don't know what to use for this motor, I've been looking around but it's confusing for me, do you guys have any idea of which stepper controller I could use ?
Thanks!

Robin2

My guess is that the DRV8825 (and probably the A4988) should work - certainly better than an L298.

Has the motor 4 wires? And have you checked with your multimeter to identify the pairs for the 2 different coils?

What motor power supply do you have? (volts and amps)

How have you adjusted the current limit on the DRV8825? I would start with it set for 500mA.

Try the first program in this Simple Stepper Code

...R
Stepper Motor Basics
Two or three hours spent thinking and reading documentation solves most programming problems.

Lothean

Hi!
Yes, I did! I even marked them as pairs
I already tried a test sketch before with all those power supplies and also while I was trying some different current limits:
PSU1: 12V 5A
PSU2: 9V 2.5A
PSU3: 24V 10A
All of these PSUs were working with my other stepper, but the one in question was not working at all.
So the issue is definitely coming from the motor itself? And why does it works with the L298N ?
Thanks for giving a little bit of your time helping me!

Robin2

I already tried a test sketch before with all those power supplies and also while I was trying some different current limits:
PSU1: 12V 5A
PSU2: 9V 2.5A
PSU3: 24V 10A
This is a bit confusing. I was not referring to the current limits of the power supplies. I was referring to the adjustment on the DRV8825 to limit the current.

Have you any means to check if the DRV8825 is broken? Disconnecting the wires between a motor and a stepper driver while the driver is powered is the quickest way to ruin a driver.

What stepper driver are you using with the motor that works?

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

Lothean

I started with 500mA and went upto 1.5A
The DRV8825 isn't broken, I have a few of these and they all work fine with the other motor.
I'll try to explain the setup more clearly:
Motor 1: the scanner motor
Motor 2: another test motor
The combination of motor 1 and L298N "works" (but it's not working properly as explained previously),
the combination of motor 2 and L298N works,
the combination of motor 2 and DRV8825 works,
the combination of motor 1 and DRV8825 does not work
Is it clear enough or my English is too broken ? :/

outsider

Try one of these:
http://www.mpja.com/Stepmotor-Driver-3A-Max-TB6560/productinfo/31306+MS
They are good to have around for "testers" too. I've seen them at other stores for less than $10 but can't remember where, shop around.

Robin2

Is it clear enough or my English is too broken ? :/
Your English is fine.

You have provided a lot of useful additional information in that Reply.


One thing you have not told us (IIRC) is how many steps per second you have been trying with the DRV8825 and motor 1.

Assuming it is not working even with a very slow step rate then it may be that it requires more current and the suggestion of @outsider may help.

When you try to drive motor 1 with the DRV8825 does it become more difficult to rotate the motor shaft with your fingers? If so it would suggest that something useful is happening.

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

Lothean

@robin2 : I tried 1step per second, and it didn't even worked at all, the motor could still be moved by hand, no holding torque

@outsider : I had a look and it has a convenient STEP/DIR interface, it also costs only 8€, thanks for this! I'll buy this one anyway since I need a beefy Stepper Motor Controller for another project

Robin2

@robin2 : I tried 1step per second, and it didn't even worked at all, the motor could still be moved by hand, no holding torque
Having no holding torque seems strange.

I know this is a silly question but have you the correct setting for the enable pin on the driver?

Can you connect your multimeter (set so it can read amps) between the driver and one of the motor coils so that you can see if the driver is causing current to flow. MAKE SURE to do all the connecting and disconnecting while the driver is unpowered and make sure that none of the connections can disconnect by accident. Measure the current while driver is powered up and the motor is not being commanded to move.

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

Lothean

Yes, the EN pin is held LOW, the RESET and SLEEP pins are held HIGH
There's just 1.3mA flowing when the voltage is around 1V at best (it fluctuates from 0 to 1V)


Robin2

Yes, the EN pin is held LOW, the RESET and SLEEP pins are held HIGH
I never know whether EN should be HIGH or LOW so I assume you have read the documentation :)


Quote
There's just 1.3mA flowing when the voltage is around 1V at best (it fluctuates from 0 to 1V)
I don't know where, or with what you measured the voltage. I can't imagine how there could be 1V anywhere if there is a 12v power supply. Can you post a diagram showing all the circuit connections when you were measuring the current and voltage. And can you confirm that your Arduino program was not sending any step commands.

If you were doing the measurements the way I envisage them being done I would suspect a failed stepper driver.

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

Lothean

Yes I did read the documentation before coming here asking for help haha ;)
I've made this to explain:

So no step from the arduino.
I tried (again) this driver with another stepper motor and it works
That's bizarre

Robin2

I believe you should be measuring the voltage between B2 and B1 as that is the voltage that drives the current through the coil.


...R
Two or three hours spent thinking and reading documentation solves most programming problems.

outsider

You said that you identified 4 wires as 2 coil pairs with R of 5.8 Ohms, were there any more wires besides the 4?
If you put 9V across one of the coils, (just long enough for testing), about 1.55 Amps should flow and the motor should resist turning by hand, have you tried that on both coils?

Lothean

Try one of these:
http://www.mpja.com/Stepmotor-Driver-3A-Max-TB6560/productinfo/31306+MS
They are good to have around for "testers" too. I've seen them at other stores for less than $10 but can't remember where, shop around.

This driver is perfect! Now it works fine
Thank you everyone for your time! :)

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