[Richard Wallace]

Originally Posted by Billfred;152642e9

I'd use either, no hesitation. Just make sure you use the same one for both sides if you have more than one motor in play on a mechanism. Rookie-year us saw a team member wire all of one side of the drive with Victor 884s and the other with Victor 888s. The 888s had a far more linear response, so they wondered why the robot would pull to one direction. Sure enough, when everything went to 888s the issue went away!

Building a little on Billfred's comment above --

Linear response (steady state RPM vs. PWM demand) is important in many robot mechanism controls. Tom Line (1718) presented some results on this, and Ether has used my Whirlpool motor lab to make the linearity comparison of several controllers when they are driving a CIM motor with dynamometer load. We are still working to extend that comparison to the latest controller types.

While those results are not complete now, I can say that the SPARK and Victor SP controllers showed very similar linearity. Our early results also confirm CTRE's results (again using CIM motor with dynamometer loading) regarding forward voltage drop across the controllers vs. load current.

As others have said, I think most teams will (and should) use controllers they have on hand, or choose new ones based on cost and features. I like SPARKs for their price, flashy lights, and screw terminals -- the latter allow me to select the lead length I want now without worrying that I might need longer leads later on.