October 6, 2018 at 2:57 pm #5791
I would like to setup a rig that uses an arduino to control a HobbyCNC board to run a stepper motor. I have power to the board. I know that pin 2 is for X direction and Y is for Step. I assume that these pins are driven from low and high commands. My question is what are the voltages for low and high for this board? -5/+5, 0/+5??
To drive one channel, what is the minimum input to get the motor to step?
MikeOctober 6, 2018 at 3:56 pm #5792
Here’s a snip from the Driver Chip spec sheet:
VDD = 5V
Logic Low: 1.25V (or lower)
Logic Hi: 3.75V (or higher)
Step and Direction signals from the 25 pin D are routed directly to the driver chip.
You must be logged in to access attached files.October 9, 2018 at 4:43 am #5820
So I took a 12v battery and powered the board. I connected a stepper motor to one channel and then ran a wire from the 5v test pad to pin 3 (X – step) and touched it repeatedly. I did not get any movement from the motor. Sounds like I did everything right. I will recheck and try again.
MikeOctober 9, 2018 at 8:51 pm #5823
I upped my voltage to 16v so I maintain above 12v while testing. I have tried all 4 axis and can get none to work while setting the step pin to 5v. I think only one axis was bad on this board so I should be able to get one axis to work. I just am not sure what I am missing. 16v to power the board and 5v to the step pin and the motor should move to the next position right?
MikeOctober 9, 2018 at 11:25 pm #5834
Could be a bunch-o-things.
First things first: Look at the FAQ Assembly Tips & Tricks. Scroll down to the section ‘The “Before you ask for help” Checklist‘, specifically numbers 1 through 7. With number seven being the import one.
Review the FAQ No Motor Movement.
Give me a status report based on your findings!
BrianVOctober 11, 2018 at 8:33 pm #5843
Sorry I did not start with this. I do think I have it figured out. See the last comment.
1. Computer: Arduino eventually. Testing is by applying 5v to pin 3 to see if it steps.
2. I verified
Power (and polarity) to the board. —16.5VDC
Test point at 5V. —5.01VDC
Power supply able to deliver enough current. —Battery capable of supplying 80 amps.
3. V-ref is set to 0.14 VDC.
I have  1.64 oz-in steppers. PK266-01A-C23 Currently there is no load on the stepper.
I have double-checked the stepper motor wiring.Yes, BLACK,GREEN,YELLOW,WHITE,BLUE,RED
I have microstepping enabled. I have tried J1, J2, J3, J2&J3
The motors [do] lock up (can NOT turn them by hand with power applied).
I have tried all 4 channels on the board using the correct step pin for each channel.
I looked up the specs for the driver ship SLA7062M and verified 5v at pin 6 and 16.5v at pin 16.
I then found that pin 2 goes to pin 10 on the driver chip. I found 5v at pin 10 so when I now drive it to low the motor steps. I thought I had to drive it to HI to step. Glad I figured it out.
The last little issue that I ran into is the Arduino (Teensy 3.2) that I am using only outputs 3.25v and the HobbyCNC board needs 3.75v so I will have to add something to step up the voltage.
Thanks for your help. Hope this helps someone else.
1 user thanked author for this post.October 11, 2018 at 11:12 pm #5844
It’s always something. Yes, the step requires a low-going pulse.
Didn’t even think of that.
Good detective work.
Regarding the arduino board. Remember we need a low-going pulse (of course you remember, you just figured that out), and the arduino will have no problem getting below Vin Low. My board has 10k pull-up resistors to +5VDC.
IF the arduino chip output pins can handle 10k pulled-up to 5V, then you should be in like Flynn.
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