Motor Shield Stepper External Power Question

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reisod
 
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Motor Shield Stepper External Power Question

Post by reisod »

Hi, I'm a bit of a newbie to stepper motor control.

I just assembled my first adafruit motor shield and want to control two stepper motors.

The stepper motors are:
12V bi-directional 4-phase unipolar stepper motor with a 1.8 degree step angle (200 steps per revolution) with a 5mm shaft.
Holding torque is 830g cm (8.14Ncm)
Coil resistance 75 Ohms
Current per coil 160mA
Phase inductance 60 mH
12V rating
6 leads Winding 1 = Brown A, White O and Red A! Winding 2 = Orange B, Black O, Yellow B!

I would like to control two of these from the Motor Shield.

I assembled the motor shield and tested with a servo, everything worked fine.

Initially I tried the configuration with one Stepper connected to M1/M2 - took the example sketch and applied settings for my motor:
AF_Stepper motor(200, 1); I uploaded the sketch to the arduino - then connected a 12V 1200mA regulated DC power supply to the motor shield, jumper disconnected. LED lights up, but no movement from the motor. The H-Bridge started getting hot, so I disconnected the power source.

Disconnecting the motor I tried powering up again - LED lights up, H-Bridge started getting hot again, so I disconnected the power source again. At this point I'm kind of stuck and have a few questions.

At 12V 160mA - the Steppers seem okay for the H-Bridge to handle?
I'm correct in keeping the jumper off?
Is my external power source ok?

To the best I can tell, the solder joints seem decent.

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adafruit_support_bill
 
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Re: Motor Shield Stepper External Power Question

Post by adafruit_support_bill »

If the H-bridge is getting hot with nothing connected, you probably have a short on the board somewhere. Can you post some photos of the front & back of the board?
At 12V 160mA - the Steppers seem okay for the H-Bridge to handle?
I'm correct in keeping the jumper off?
Is my external power source ok?
yes to all of the above.

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reisod
 
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Re: Motor Shield Stepper External Power Question

Post by reisod »

Hi
Thanks for your response. Attached are photos of the front and back of the shield.
Attachments
photo (3).JPG
photo (3).JPG (137.35 KiB) Viewed 2660 times
photo (2).JPG
photo (2).JPG (139.58 KiB) Viewed 2660 times

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adafruit_support_bill
 
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Re: Motor Shield Stepper External Power Question

Post by adafruit_support_bill »

I don't see any obvious problems with the assembly.

Disconnect all motors and the external power supply.
Install the jumper (we'll use the Arduino supply for the moment. It is less likely to fry anything);
Power up the Arduino & shield and:
1) see if the bridge-chips are still getting hot.
2) see if the Arduino is resetting - or not starting up at all. If there is a short, the Arduino itself will likely reset due to the voltage sag.

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reisod
 
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Re: Motor Shield Stepper External Power Question

Post by reisod »

Thanks again. I disconnected everything as you suggested and connected the arduino power supply. There doesn't seem to be any problems (the bridges are not getting hot, and the board is starting up just fine and not resetting). Would this suggest that there is an issue with the power supply?

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Re: Motor Shield Stepper External Power Question

Post by adafruit_support_bill »

Possibly. Are you sure it is a DC supply? Do you have it connected with the right polarity?

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reisod
 
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Re: Motor Shield Stepper External Power Question

Post by reisod »

The supply is listed as a 1200ma Regulated DC Power Supply ( AC Adaptor ). A trim pot allows changing voltages from 1.5, 3, 4.5, 6, 7.5, 9, & 12Vdc. I trimmed off the barrel plug - and tested the leads with my volt meter with the adaptor set to 12V. When the volt meter read 12V ( not -12V ) I marked the ground and lead to correspond with the ground and lead from the volt meter. I'm connecting the marked ground to ground on the motor shield EXT terminal, and the marked lead to the + on the EXT terminal.

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reisod
 
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Re: Motor Shield Stepper External Power Question

Post by reisod »

Tried reconnecting and found that there was a short in the breadboard. Thanks for all your help.

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Re: Motor Shield Stepper External Power Question

Post by adafruit_support_bill »

Great! :D

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rmm200
 
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Re: Motor Shield Stepper External Power Question

Post by rmm200 »

You folks are way underpaid for the help and advice you provide. I just hope your attitude turns into tons of sales!

Sorry - good customer service is rare - and I just had to comment...

Robert

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Re: Motor Shield Stepper External Power Question

Post by adafruit »

rmm200 wrote:You folks are way underpaid for the help and advice you provide. I just hope your attitude turns into tons of sales!

Sorry - good customer service is rare - and I just had to comment...

Robert
Thanks robert! we try hard to provide the best customer service for all the products we sell

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