<p>The described behaviour could happen if, e.g. <code>X_STEP_PIN</code>, <code>X_DIR_PIN</code> and <code>X_ENABLE_PIN</code> are not correctly mapped.
I guess you will find them in <code>pins_RAMPS_144.h</code>. Make sure the correct file is used.</p>

CC BY-SA 4.0
2021-02-15T22:51:40.323Z
2021-02-15T22:51:40.323Z
dotswe
<p>I am trying to control stepper motors for a 3D printer with a RAMPS 1.4 shield connected to an Arduino Mega 2560. I have uploaded Marlin firmware to the board and am currently using Pronterface to test the board's components.</p>
<p>At first, the stepper motors would not move at all when commanded. They would just slightly twitch and them hum, but not rotate. Then, I checked the wiring connections and ensured they were correct, but the problem persisted. Then, I measured the Vref of the stepper drivers, which was 0.79 Volts.</p>
<p>Based on my stepper motors, NEMA 17, the maximum Vref I calculated was 1.36 Volts. After adjusting the potentiometer screw the maximum amount, Vref is 1.19 Volts. Now, the motors WILL rotate when given the 0.1 and 1 command in Pronterface, but return to the twitch and whine behavior when given the 10 or 100 command. What is the cause of this?
<a href="https://i.sstatic.net/372nN.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/372nN.png" alt="enter image description here" /></a></p>

CC BY-SA 4.0
2021-02-10T15:57:40.307Z
Please give us your calculations. There is a lot that you seem to be missing. e.g. the potentiometer doesn't adjust the voltage...
user77232
CC BY-SA 4.0
2021-02-10T20:23:42.640Z
I used the equation Vref = I_max * 8 * R_sense. For my stepper, I_max is 1.7 A, and on the driver, R_sense is 0.1 Ohms.
Ethan Guidry
CC BY-SA 4.0
2021-02-10T22:09:37.967Z
I_max is 1.7 A at what voltage?
user77232
CC BY-SA 4.0
2021-02-10T22:15:20.937Z
Please iclude these details to question. As well as configured speed and acceleration settings (e.g. output of [`M503`](https://marlinfw.org/docs/gcode/M503.html), btw. do you use Marlin?). Does the problem persist when you lower the max speed ?
octopus8
CC BY-SA 4.0
2021-02-12T15:17:40.247Z
To user77232, I_max is 1.7A at 12V. To octopus8, I've attached a picture of my Marlin configuration.h file that shows the movement settings I've configured. I'll admit I'm a rookie where all this is concerned, so I'm not exactly sure of what I'm doing with these settings. Thank you!
Ethan Guidry
CC BY-SA 4.0
2021-02-14T17:58:27.467Z
This could be caused by faulty stepper driver, stepper motor or connection between the stepper driver and the motor or between the stepper driver and the microcontroller. What stepper drivers are you using? I assume you bought all of these parts from China on Aliexpress or eBay or whatever. The connections on these boards can be noisy producing false signals between the microcontroller and the stepper driver.
TurgonTheKingOfGondolin
<ramps-1.4><stepper>
Confusing stepper motor behavior
Ethan Guidry
# Confusing stepper motor behavior

(Asked by: username_0 on 2021-02-09)

I am trying to control stepper motors for a 3D printer with a RAMPS 1.4 shield connected to an Arduino Mega 2560. I have uploaded Marlin firmware to the board and am currently using Pronterface to test the board's components.

At first, the stepper motors would not move at all when commanded. They would just slightly twitch and them hum, but not rotate. Then, I checked the wiring connections and ensured they were correct, but the problem persisted. Then, I measured the Vref of the stepper drivers, which was 0.79 Volts.

Based on my stepper motors, NEMA 17, the maximum Vref I calculated was 1.36 Volts. After adjusting the potentiometer screw the maximum amount, Vref is 1.19 Volts. Now, the motors WILL rotate when given the 0.1 and 1 command in Pronterface, but return to the twitch and whine behavior when given the 10 or 100 command. What is the cause of this?
[![enter image description here](https://i.sstatic.net/372nN.png)](https://i.sstatic.net/372nN.png)

**Tags:** ramps-1.4, stepper

> **Comments:**
> **username_1**: Please give us your calculations. There is a lot that you seem to be missing. e.g. the potentiometer doesn't adjust the voltage...  
> **username_0**: I used the equation Vref = I_max * 8 * R_sense. For my stepper, I_max is 1.7 A, and on the driver, R_sense is 0.1 Ohms.  
> **username_1**: I_max is 1.7 A at what voltage?  
> **username_2**: Please iclude these details to question. As well as configured speed and acceleration settings (e.g. output of [`M503`](https://marlinfw.org/docs/gcode/M503.html), btw. do you use Marlin?). Does the problem persist when you lower the max speed ?  
> **username_0**: To username_1, I_max is 1.7A at 12V. To username_2, I've attached a picture of my Marlin configuration.h file that shows the movement settings I've configured. I'll admit I'm a rookie where all this is concerned, so I'm not exactly sure of what I'm doing with these settings. Thank you!  
> **username_3**: This could be caused by faulty stepper driver, stepper motor or connection between the stepper driver and the motor or between the stepper driver and the microcontroller. What stepper drivers are you using? I assume you bought all of these parts from China on Aliexpress or eBay or whatever. The connections on these boards can be noisy producing false signals between the microcontroller and the stepper driver.  

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## 1 answers

### Answer by username_4 on 2021-02-15. Score: 1

The described behaviour could happen if, e.g. `X_STEP_PIN`, `X_DIR_PIN` and `X_ENABLE_PIN` are not correctly mapped.
I guess you will find them in `pins_RAMPS_144.h`. Make sure the correct file is used.


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