PDA

View Full Version : Sabertooth 10a problems



Droid Works
04-19-2008, 07:40 PM
I have a : http://www.trossenrobotics.com/store/p/5106-Sabertooth-dual-10A-motor-driver-for-R-C.aspx And I can not get it to recognize a PWM signal. I have tried every jumper setting possible. I tried different controllers like SSC-32, Basic Stamp, bot board, ect and I cant get it to use a PWM signal. Is there a line of code I have to enter or some trick to getting it to work...lol

Alex
04-19-2008, 11:45 PM
hmm.... there have been a few problems with the sabertooth controllers. You may have gotten a bad one but I can't say for sure. Dave knows much more about this issue than I do. If possible wait till Monday to do anything more with the controller, and I'll have him chime in on this thread. I'd hate to see you spend a crap ton of time trying to get the controller to work only to find out it's a bad controller:(

JonHylands
04-20-2008, 07:22 AM
Funny, I have a couple of those, and the only thing I could get it to recognize was a PWM signal.

A couple caveats:

- the PWM signal is locked anti-phase, which means at 50% duty cycle, the motor will be stopped. At 0%, you'll get full reverse, and at 100% you'll get full forwards
- I had to put a really big honking capacitor between each PWM pin and ground. Really big, like 600 uF electrolytic...

Hope this helps.

- Jon

Alex
04-20-2008, 03:01 PM
Jon just helped me remember something. I'm not sure if this is how the sabertooths work, but I know that with some PWM motor controllers you need to send out a 1.5 ms pulse out initially before you can send out any other PWM signals. You'll need to experiment with this a bit, because sometimes I need to send exactly 1.5ms, sometimes 1.53, 1.48, 1.57, etc.

Droid Works
04-20-2008, 07:25 PM
Funny, I have a couple of those, and the only thing I could get it to recognize was a PWM signal.

A couple caveats:

- the PWM signal is locked anti-phase, which means at 50% duty cycle, the motor will be stopped. At 0%, you'll get full reverse, and at 100% you'll get full forwards
- I had to put a really big honking capacitor between each PWM pin and ground. Really big, like 600 uF electrolytic...

Hope this helps.

- Jon

I tried that. the only motion I can get out of the motors is when turn off auto calibrate and it moves forward.

Droid Works
04-20-2008, 07:29 PM
Jon just helped me remember something. I'm not sure if this is how the sabertooths work, but I know that with some PWM motor controllers you need to send out a 1.5 ms pulse out initially before you can send out any other PWM signals. You'll need to experiment with this a bit, because sometimes I need to send exactly 1.5ms, sometimes 1.53, 1.48, 1.57, etc.

I tried 750-2500 and 1.5-2.0 and still nothing. I think I may have gotten a bad one.

Dave
04-21-2008, 04:34 PM
DW: If turning off the auto-cal setting doesn't fix it, then it sounds like you got one of the flaky ones. Email me your order number and I'll get a new one sent out to you.

JH: Are you sure you didn't have the controller set to analog input mode? That cap you used shouldn't be necessary.

Adrenalynn
04-21-2008, 04:46 PM
I turned-off auto-cal early on, and mine works "sometimes" if I pulse it first @ 1.5. Sometimes, it sits like a lump. Sometimes it works happily.

Always works when plugged in to a Futaba receiver, though...

Droid Works
04-21-2008, 11:17 PM
I turned-off auto-cal early on, and mine works "sometimes" if I pulse it first @ 1.5. Sometimes, it sits like a lump. Sometimes it works happily.

Always works when plugged in to a Futaba receiver, though...

Mine is in a constant lump state..lol I think its just a bad one. Im going to chuck it and use the BaneBots Motor Controller (45A peak) instead. I have the 9a bb and it works great.

JonHylands
04-22-2008, 06:13 AM
Ahhh, I was getting confused - for some reason I thought you were talking about the non-RC version of the Sabertooth, which is what I use... Ignore everything I said about locked anti-phase...

- Jon

Dave
04-23-2008, 04:11 PM
I turned-off auto-cal early on, and mine works "sometimes" if I pulse it first @ 1.5. Sometimes, it sits like a lump. Sometimes it works happily.

Always works when plugged in to a Futaba receiver, though...

What have you been using, besides the Futaba receiver, as a control signal source?

Adrenalynn
04-23-2008, 05:10 PM
The SSC-32

LinuxGuy
04-23-2008, 05:17 PM
Ahhh, I was getting confused - for some reason I thought you were talking about the non-RC version of the Sabertooth, which is what I use... Ignore everything I said about locked anti-phase...
I have the non-R/C only version of the Sabertooth 2x5 and I've never had problems with it. I wonder if this is a problem unique to the R/C only Sabertooth controllers.

8-Dale

JonHylands
04-24-2008, 07:50 AM
I've used a couple non-RC Sabertooth 2x10 amp boards and the 2x25 amp version with no trouble.

- Jon

Adrenalynn
04-24-2008, 10:52 AM
Looking at the output on the SSC-32 on the 'scope, I suspect I have a code bug, maybe not a motor-controller bug. I'd like to at least temporarily retract my comments until I've had time to investigate this weekend.:o

Adrenalynn
04-26-2008, 03:37 AM
I'd like to acknowledge that my issue with the Sabertooth R/C was with my code, not the motor controller or the SSC-32. I need to send a pulse of 1500us, not 1.5us :o

In mixed-mode, Channel 0 works as 0-100% forward/reverse, Channel 1 as 0-100% left/right rotation
In independant mode, Channel 0 is right-track forward/back, Channel 1 is left-track forward/back (standard tank controls), both independant 0-100%