Driving a Bipolar stepper with 2 jaguars

[teslalab2]

https://www.youtube.com/watch?v=qkiRm1yStdk

I had a 6 hour drive the other day, and I dreamed this up. I thought I would try it, and it actually worked. It would be fun to try and use jaguars to drive a 3d printer

sorry this is kinda stupid and hardly FIRST related.

[asid61]

Neat! What a weird way to do this. Is the 6ms limit on the refresh rate on the output voltage, or just for forward/stop? You could try and bring it to around 4% or so instead of full stop to get extra speed.

[teslalab2]

at first it starts to skip steps if you go any faster than that. If you keep upping it, eventually the first jaguar will become un-responsive on the can-bus and stop bridging the second one it affectively crashes...

edit: I just realized adding the can terminator at the end would probably fix the bridge crashing

[asid61]

Originally Posted by teslalab2

at first it starts to skip steps if you go any faster than that. If you keep upping it, eventually the first jaguar will become un-responsive on the can-bus and stop bridging the second one it affectively crashes...

edit: I just realized adding the can terminator at the end would probably fix the bridge crashing

Crashing a Jaguar, wow. Maybe accelerate up to the target speed with some ramping? I know that some stepper-abusive libraries do that.

[teslalab2]

Its not a library its some crap code sketch I just quickly wrote. and if you are running can, the bridge jaguar can crash if you do some stupid stuff.But it could also owe to the fact that I didn't put the 100 ohm terminator on the last jaguar.

[techhelpbb]

The world's least cost effective hack .

The RAMPS modules on 3D printers use Allegro stepper drivers which are already MOSFET based.
Considers you can drive a whole stepper off 1 $8 stepper board...

[EmileH]

Originally Posted by techhelpbb

The world's least cost effective hack .

But... it's the most cost effective hack if you already have the materials.

[teslalab2]

It might not be cost effective, for a little nema 17 on a 3d printer... but cost effective for driving a huge stepper. Now I could power a stepper up to 60 amps!

[asid61]

Originally Posted by teslalab2

It might not be cost effective, for a little nema 17 on a 3d printer... but cost effective for driving a huge stepper. Now I could power a stepper up to 60 amps!

I think I found the next FRC-legal motor... and the SRX will take care of the code.

[techhelpbb]

Originally Posted by teslalab2

It might not be cost effective, for a little nema 17 on a 3d printer... but cost effective for driving a huge stepper. Now I could power a stepper up to 60 amps!

I would be surprised if that would be useful:

Cause you do not have the voltage with the Jaguars to put it to use with the steppers most people use.

I haven't put much thought into it, but most of my high power steppers use 50V supplies. I think you'd need a stepper with a fairly unusual set of windings to get 60A from even a solid, trickle charged, online battery.

Originally Posted by EmileH

But... it's the most cost effective hack if you already have the materials.

Maybe opportunity cost Mr/Miss MacGyver .

http://www.cbs.com/shows/macgyver/

[teslalab2]

well there is one way to find out. I'll go grab a nema 34 (I know this one is only 10 amps) from work and put this to the test. Some where we have a spare huge stepper for the X-axis from our quad iv-c mkii pick and place, which we no longer have. I think my boss would let me use that too. the more logical thing would be just to use the jags to drive a servo... but ahh over complicate all the things.

[Gdeaver]

What about micro stepping? Stepper drivers chop to control current. Nema 17's run OK at 12 volts but perform better at 24 volts. Nema 23's perform much better at 24 volts and more for the larger ones. I like TI dvr 8825's for up to 2.2 amps at 24 volts. The Toshiba drivers TB6600 and newer are good up to 4 to 5 amps and up to 40 volts. Above 5 amps 2 discrete H bridges are needed and they use a micro controller with DSP to do the micro step translation and some other tricks to control mid velocity harmonics. Talons are not designed for stepping.