What could be the reasons that stepper motor is not rotating? - Page 1
Forum section: electronics / general

author: eeguy
author_rank: Regular Contributor
timestamp: April 04, 2024, 08:42:46 pm
content: Hello, I connected a stepper motor to a DM556T motor driver and Arduino. Upon powering up, I heard a continuous faint noise from the motor but there was no rotation. I could not rotate the motor by hand but after turning off the power, I could do so. Could be that the motor was locked to a position. Am I supposed to leave ENA+ and ENA- alone without connecting them to anything. The manual is a bit confusing. Also, am I supposed to connect the GND of the Arduino to that of the DM556T. Did not seem to make any difference. What could be possible reasons for the motor not to rotate? I used a multimeter to confirm that PUL+ was varying between 2.5V and 0V.https://www.omc-stepperonline.com/digital-stepper-driver-1-8-5-6a-20-50vdc-for-nema-23-24-34-stepper-motor-dm556t

author: thm_w
author_rank: Super Contributor
timestamp: April 04, 2024, 08:56:56 pm
content: You can read the datasheet, ENA does not need to be connected if you want the drive always enabled.Its normal that the motor will not rotate when it has been enabled, until you feed it a signal.Have you connected PUL- and PUL+, and see that they recommend 4-5V signal?

author: eeguy
author_rank: Regular Contributor
timestamp: April 04, 2024, 09:06:25 pm
content: Do you mean connecting PUL- to PUL+? Currently, PUL+ is connected to digital port 9 of Arduino while PUL- is connected to GND of the Arduino.I wired everything like the following diagram except that there is no PSU 5V to the Arduino as it gets power from the USB port connected to a PC and the PSU to the motor driver is 24V.https://help.stepperonline.com/en/article/can-you-send-me-a-schematic-that-how-to-wire-the-stepper-driver-to-an-arduino-d5ot82/

author: thm_w
author_rank: Super Contributor
timestamp: April 04, 2024, 09:47:44 pm
content: Check the motor windings are connected correctly, A+ to A- should read a low resistance to represent the coil in the stepper motor.Do you have another 5V source you can try to trigger the PUL pin with? 2.5V might be too low of a signal.

author: eeguy
author_rank: Regular Contributor
timestamp: April 04, 2024, 09:55:42 pm
content: Quote from: thm_w on April 04, 2024, 09:47:44 pmI tested the connections of the windings with the power to the controller turned off. When connecting the probes of the multimeter to A+ and A- or B+ and B-, it beeped. Otherwise, no sound.I connected a 5V port from Arduino directly to PUL+ but nothing changed.When I placed the probes of a multimeter between PUL+ and PUL-, I got 5V. However, when I placed the probes between PUL+ and GND of the DM556T, I got close to zero (in mV). Is this normal?

author: thm_w
author_rank: Super Contributor
timestamp: April 04, 2024, 10:13:27 pm
content: That is normal yes. PUL+/PUL- is an isolated input, which is why PUL- needs the GND arduino connection.When you connected 5V, did you try just tapping it on the connector to get a bunch of pulses to come through?Set the step size to the lowest pulse/rev (200) if not already, to get the most motion. Though even if its on the higher settings you should see it already move a little...

author: eeguy
author_rank: Regular Contributor
timestamp: April 04, 2024, 10:22:50 pm
content: I manually connected and disconnected the wire from the 5V port of the Arduino to simulate a series of pulses but nothing changed.I set the step size to 200 pulse/rev in the Arduino code and changed the switches on the controller correspondingly to match the 200 pulse/rev. However, the situation is still the same.With the PUL+ back to Digital port 9 of Arduino, I measured the voltage between GND of DM556T and A+, I got 12.96V. Between GND and A-, 11.14V. Between GND and B+ 12V, Between GND and B- 12.02V. All constant values. Are they supposed to stay constant all the time?

author: thm_w
author_rank: Super Contributor
timestamp: April 04, 2024, 11:51:41 pm
content: We mostly care about A+ to A-. So that would mean A+ to A- is about 2V, and B+ to B- is 0V. This would be normal steady state for a full step held in one spot.https://www.engineerlive.com/content/fundamental-principles-stepper-motorsIf you pulse in a step it should change through the various states.But not sure if a reading of 12V is normal, for sure the supply is reading as 24V right?

author: eeguy
author_rank: Regular Contributor
timestamp: April 04, 2024, 11:56:00 pm
content: A+, A- B+, B- should change. What could be the reasons they remain unchanged?PSU is Meanwell LRS-350-24. Multimeter showed the voltage across the GND and +Vdc ports of the DM556T is 24V.

author: thm_w
author_rank: Super Contributor
timestamp: April 05, 2024, 09:39:52 pm
content: Maybe the PUL input is dead? Not sureYou can try disconnecting the motor, and you should get 24V across A+/A- and 0V across B+/B-. Then it should switch around after pulsing.You could try feeding in 5V to ENA and then the motor should freely turn.But these don't really tell you anything definitive.