Troubleshooting motor controllers

[Jon Stratis]

From everything you've said, it sounds like everything is correctly hooked up electrically - ie nothing "shook loose" on that side of things.

Use a multimeter and make sure that the GND and +5V pins for the PWM wires you're using are reading the correct voltage. If not, your sidecar might be busted.

Do you have access to an oscilloscope? It would be nice to scope the PWM signal coming out of the digital sidecar and make sure it looks correct. If not, you can try using a multimeter set to AC Voltage. It's not perfect, but if there's no signal, you'll read 0V, and if there is one you should read a voltage.

Have you checked that all of the PWM wires are seated correctly? Sometimes they can be loose, and riding around in the back of a truck on a long bumpy drive might be enough to shake them just loose enough from the Victors that you don't get a signal anymore. It would be odd for this to happen to all of them at once, though.

Are you sure the code hasn't changed?

[Ether]

Originally Posted by Jon Stratis

If not, you can try using a multimeter set to AC Voltage.

Some DVM's use half-wave rectification for AC, and if you have the DVM leads connected the wrong way you'll read zero volts. If you use DC, you'll read voltage regardless of polarity.

[Jon Stratis]

Originally Posted by Ether

Some DVM's use half-wave rectification for AC, and if you have the DVM leads connected the wrong way you'll read zero volts. If you use DC, you'll read voltage regardless of polarity.

Good to know... I've seen with mine set to DC the results can be inconsistent, as the sampling period doesn't handle square wave forms very nicely. With AC, I've always seen decent results for quick testing. It just goes to show that testing I might do for a team in their pit can't necessarily translate very well over the internet!

[MichaelBielecki]

I did a quick search and found this online:
( http://content.vexrobotics.com/docs/...al-9-25-06.pdf ).

From what I read, a "Flashing ORANGE indicator on power up" means "No PWM signal." This is probably caused by the sidecar. Since all motor controllers are not working, it is unlikely that all of them had something happen to them that would be causing this. It is more likely that the source of the pwm signal (the sidecar) which they all share in common is causing the problem. A couple things you can do to check the side car is to first look at it and see if there is anything visibly shorting or if something is plugged in backwards. Another this that could be causing this is chips. You can try to clean out the chips if you see any and try again. The signal light pattern would help identify the problem. Is the RSL blinking when you plug it in or is it a solid on or off? I ask because one of my teams sidecars went bad and the signal light would not turn on. If you don't see a problem, you can try unplugging everything from the sidecar except for one motor controller. See if it works. If not, try getting a new, unused motor controller if you have one to test the sidecar.

I hope this helps

[danruff5]

Thanks MichaelBielecki. The RSL is always solid.

Another this that could be causing this is chips. You can try to clean out the chips if you see any and try again.

I will try this now.

EDIT
I tried this and still no change.

you can try unplugging everything from the sidecar except for one motor controller.

Next this.

EDIT
Still no change.

[roystur44]

We use this to generate a pwm signal to a motor controller. Great device to have to test the motors without hooking up the electronics.

http://www.servocity.com/html/dual_servo_driver.html

[lcoreyl]

Originally Posted by roystur44

We use this to generate a pwm signal to a motor controller. Great device to have to test the motors without hooking up the electronics.

http://www.servocity.com/html/dual_servo_driver.html

IMO that $50 would be better served towards an arduino with a potentiometer. This gives you a tool with endless possibilities (including acting as a motor controller). Actually, AndyMark now has a shield for an arduino that can make it replace your cRIO for testing, which makes an arduino all the more valuable.

[Ether]

Originally Posted by roystur44

We use this to generate a pwm signal to a motor controller. Great device to have to test the motors without hooking up the electronics.

http://www.servocity.com/html/dual_servo_driver.html

Originally Posted by lcoreyl

IMO that $50 would be better served towards an arduino with a potentiometer. This gives you a tool with endless possibilities (including acting as a motor controller). Actually, AndyMark now has a shield for an arduino that can make it replace your cRIO for testing, which makes an arduino all the more valuable.

Or spend $0 and make one with an old junker laptop.

[lcoreyl]

Originally Posted by Ether

Or spend $0 and make one with an old junker laptop.

Wow, fantastic! We're always looking for cheap solutions using old "trash".

[Ether]

Originally Posted by lcoreyl

Wow, fantastic! We're always looking for cheap solutions using old "trash".

See posts 17 thru 21 in this thread:

http://www.chiefdelphi.com/forums/sh...d.php?t=115970

[roystur44]

I don't have one but I saw this and it looks kinda cool.

http://www.robotshop.com/seeedstudio-dso-nano-v2-1.html


http://www.robotshop.com/oscilloscopes-generators.html

[danruff5]

Originally Posted by lcoreyl

IMO that $50 would be better served towards an arduino with a potentiometer. This gives you a tool with endless possibilities (including acting as a motor controller). Actually, AndyMark now has a shield for an arduino that can make it replace your cRIO for testing, which makes an arduino all the more valuable.

This sounds AWESOME!!! Thanks for telling me!

We replaced the digital sidecar and now it works perfectly!

Thanks to everyone who gave suggestions!

[slijin]

Originally Posted by danruff5

This sounds AWESOME!!! Thanks for telling me!

We replaced the digital sidecar and now it works perfectly!

Thanks to everyone who gave suggestions!

Great to hear that.

Could you open up the bad DSC and have a look inside? I'm sure I'm not alone in wanting to understand why a DSC that appeared perfectly functional wasn't actually working.

[danruff5]

Originally Posted by slijin

Could you open up the bad DSC and have a look inside?

I have done that, I could not see any physical damage to the DSC.

[404'd]

Originally Posted by danruff5

Thanks MichaelBielecki. The RSL is always solid..

You say the RSL is always solid, even while disabled it does not blink?

I would try swapping Sidecars if you have a spare.