Ramps Board - Stepper Motor Issues

Thread Starter

scbullock

Joined Aug 19, 2023
69
Hi,
My ramps 1.4 board indicates 2B 2A 1A 1B for motor connection. The base version of the motor wiring is 2B 2A 1B 1A. I learned this by taking a look at my motor spec sheet (nema-17) & the meaning of 2B 2A 1A 1B. I concluded that the 4 pin connector needed a switch between the black (1A or A+) and green (1B or A-) to match the 2B 2A 1A 1B configuration. That just caused my motor to vibrate. What is wrong here?
 

dendad

Joined Feb 20, 2016
4,503
Yes, those small trim pots set the motor current. There are some Youtube videos somewhere talking about them too.
 

MisterBill2

Joined Jan 23, 2018
19,398
It would be useful for the TS to state an actual problem, rather than just a difference. I do have stepper motor experience from years ago, the physics has not changed. But a statement of an apparent problem could lead to somebody having a solution. With no problem stated no advice will be offered.
 

dendad

Joined Feb 20, 2016
4,503
Yes, the question is a bit vague. I take it the problem is the motor is not rotating, just vibrating.
It does sound like the motor connections are wrong. Measure the resistance of the motor from 1A to 2A and 1B to 2B to make sure they are both ok and you have not swapped windings, like 1A to 1B etc.
 

Thread Starter

scbullock

Joined Aug 19, 2023
69
Yes, the question is a bit vague. I take it the problem is the motor is not rotating, just vibrating.
It does sound like the motor connections are wrong. Measure the resistance of the motor from 1A to 2A and 1B to 2B to make sure they are both ok and you have not swapped windings, like 1A to 1B etc.
Correct, the motor is just vibrating as I stated in my first post. It is not rotating as it should when I input an incremental rotation.
 

dendad

Joined Feb 20, 2016
4,503
Are the wire's order and colours the same as the in the picture I posted?
If you have another motor, try that too. Also, try this motor in another position.
See if you can determine if there is a wiring, motor or driver problem.
 

MisterBill2

Joined Jan 23, 2018
19,398
OK, it seems that I missed the comment about the motor just vibrating. So certainly connections need to be changed. It is indeed unfortunate that there may be a difference in connections between motor suppliers.
If you have another unmounted motor that runs correctly, substituting it for the motor that just vibrates will allow verification as to if it is a connection issue or a driver board issue. The other possible cause would be a motor internal connection fault, such as a wire in the connector not having adequate contact with the insert..
 

DNA Robotics

Joined Jun 13, 2014
656
Assuming you have the phase sequence wired correctly, If you send steps too fast for the motor, it will just sit there vibrating. Try sending one step at a time, or slow it way down. Once you get it working, you can speed it up.
 
Last edited:

strantor

Joined Oct 3, 2010
6,837
Assuming you have the phase sequence wired correctly, If you send steps too fast for the motor, it will just sit there vibrating. Try sending one step at a time, or slow it way down. Once you get it working, you can speed it up.
+1
In addition to speed, acceleration is critical. A stepper can't go from 0 to (any speed beyond a few tens if RPM) without working up to it. If you have no accel ramp, just instantaneously sending a pulse train to the driver will result in vibration, even if the pulse train corresponds to a speed that the motor should be more than capable of achieving.

If the motor starts to spin but then stalls and vibrates, your speed is most likely the problem. If it doesn't start to rotate but just starts vibrating right away, acceleration is more likely the problem.

If I am not mistaken, Ramps is a 3D printer board that uses Marlin firmware. You should check the config in your marlin build, maybe adjust it and re-flash. Or there may be a g-code command to change the accel without reflashing, I don't remember, it has been years since I messed with Marlin.
 

Thread Starter

scbullock

Joined Aug 19, 2023
69
OK, it seems that I missed the comment about the motor just vibrating. So certainly connections need to be changed. It is indeed unfortunate that there may be a difference in connections between motor suppliers.
If you have another unmounted motor that runs correctly, substituting it for the motor that just vibrates will allow verification as to if it is a connection issue or a driver board issue. The other possible cause would be a motor internal connection fault, such as a wire in the connector not having adequate contact with the insert..
Yes, I have subsituted a motor that was working into the driver that was connected to the vibrating motor. The substituted motor worked, so I know it is not the driver causing the issue. Also, the motor is rated at 1.7 Amps. With my DRV8825 driver, that is 0.85 reference voltage. I set all the drivers to about 0.9V and am still have the vibrating issue.
In conclusion, knowing that the motor I substituted into the driver worked correctly, can we assume it is a wiring problem?

Note: This is the specific Nema 17 motor. I sent the amazon seller a message about wiring configuration. I will be back to troubleshooting on Monday.
 

dendad

Joined Feb 20, 2016
4,503
Compare the continuity of the windings of each motor to ensure you are using each winding and not using an A and a B for each phase.
 
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