Pololu Pot Tweaking?

atanguay
Posts: 36
Joined: Wed Jun 20, 2012 4:26 am

Pololu Pot Tweaking?

Post by atanguay » Thu Jul 05, 2012 3:16 am

I'm using the Buildlog Stepper Sheild and three Pololus (Poluli :? ) for my build, and I've seen mention of the ability to tweak the pots on the controllers (Pololu).

But I had yet to find anything talking about HOW they should be set, or why you'd need to change them.

My motors are turning and things seem to be going fine. I'm using the prescribed NEMA17s from Sparkfun, so it's a pretty vanilla setup.
Any ideas or advice is greatly appreciated.
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dointhangs
Posts: 179
Joined: Tue Jun 05, 2012 7:31 pm

Re: Pololu Pot Tweaking?

Post by dointhangs » Thu Jul 05, 2012 4:44 am

atanguay the electronics page on the wiki section has the section on this - you have to put the + voltmeter lead on the little spot and then then ground the other someplace. Theres a picture there. I was getting sporadic movement from my nema17's before I adjusted the voltage (current is too high for their rating). Edward was telling me at makers faire that they ship these things at a high current setting. Thats great you arent having problems as is but if anything funny starts happening you will probably want to do that.
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Burke LaShell
Posts: 90
Joined: Tue Apr 10, 2012 12:42 pm
Location: Philadelphia, PA

Re: Pololu Pot Tweaking?

Post by Burke LaShell » Thu Jul 05, 2012 12:25 pm

the electronics page on the wiki section has the section on this
Here's the link...
http://www.shapeoko.com/wiki/index.php/ ... er_Drivers

atanguay
Posts: 36
Joined: Wed Jun 20, 2012 4:26 am

Re: Pololu Pot Tweaking?

Post by atanguay » Thu Jul 05, 2012 5:57 pm

Aha! Thanks you guys. I had missed this.
Perfect
SHAPEOKO SERIAL NUMBER 303! - Home of the ShapeoKube!

PLHS54
Posts: 60
Joined: Sun Apr 22, 2012 7:36 pm

Re: Pololu Pot Tweaking?

Post by PLHS54 » Thu Jul 05, 2012 7:18 pm

This may seem like a dumb question, but when you are adjusting the drivers, should EVERYTHING be plugged in; all motors, power from power supply, and power from the computer to the arduino?

Burke LaShell
Posts: 90
Joined: Tue Apr 10, 2012 12:42 pm
Location: Philadelphia, PA

Re: Pololu Pot Tweaking?

Post by Burke LaShell » Thu Jul 05, 2012 8:41 pm

should EVERYTHING be plugged in
All you need is power to the driver shield.

atanguay
Posts: 36
Joined: Wed Jun 20, 2012 4:26 am

Re: Pololu Pot Tweaking?

Post by atanguay » Fri Jul 06, 2012 12:21 am

Any ideas how hot the heat sinks should be allowed to get?

When I plug in my PS, they start to get pretty darned hot pretty quickly.
I'm a little worried about them.
SHAPEOKO SERIAL NUMBER 303! - Home of the ShapeoKube!

Burke LaShell
Posts: 90
Joined: Tue Apr 10, 2012 12:42 pm
Location: Philadelphia, PA

Re: Pololu Pot Tweaking?

Post by Burke LaShell » Fri Jul 06, 2012 1:45 am

I found three things:
*The heat sinks can get too hot to touch
*When they get too hot it shuts down/misses steps
*A small fan blowing across the heat sinks solves that problem

CptanPanic
Posts: 98
Joined: Tue Apr 10, 2012 3:14 pm

Re: Pololu Pot Tweaking?

Post by CptanPanic » Fri Jul 06, 2012 3:00 am

With max cooling, and what is max you can turn pot up to? All the way?

levlandau2
Posts: 187
Joined: Tue Apr 17, 2012 1:52 am
Location: Minneapolis, MN, USA

Re: Pololu Pot Tweaking?

Post by levlandau2 » Fri Jul 06, 2012 3:07 am

The pots control the current going to the motor. The buildlog stepper shield guide says that V=I*0.4 , so if you measure 0.6V, that means the current going to the motors is 1.5A.

I currently have my pots set to the baseline 0.6V. I am not sure what the advantage is of running higher currents... would that damage the motors? would it make the motors run better?

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