Silent servo with gecko 320/340

[xaq]

I really like Gecko drives and have used 210s on a couple retrofits. Now I have a motor control project that has nothing to do with CNC, but I think Geckos might still fit the bill. I have a DC worm gear (6 to 1) motor with an 200 cpr encoder. I want to control the position of the motor with minimal accuracy (+-half a turn would be fine). I've never used Gecko's servo controllers, but I read that they "sing" bouncing between encoder counts. I need this system to be silent when the motors are not receiving step signals (i.e. not moving). In a perfect world I would just turn down the I component of the internal PID filter and stop the singing. However, I don't think you can do that with the Geckos (looks like you have access to Gain [P] and Dampening [D]). Because my motor uses a worm gear (not back-drivable), theoretically I could just turn off the driver and let the motor sit unpowered when it is not commanded to move. This would be nice and silent. Setting the err input low looks like it depowers the motor. I could do this each time the motor stops. However, I can't tell from the documentation how long it takes to re-enable the drive (by putting a high on err). I really can't wait 5 seconds or even 1 second for the drive to re-enable. What do you think? Should I try this with Geckos or go for a different driver that might give me more control. I am open to any advice.

Thanks in advance!
Zach

[erase42]

i know its a step down in coolness, but Spal sells a linear actuator controller for the dc actuators that open and close car doors and show car parts. its a very simple system that uses a potentiometer as an encoder of sorts. the controller is 75 dollars and has 3 presetable locations and when you ground one of three wires it goes to the preset location. just combine your motor with a multi turn pot and you have a working system. i dont know if 3 presets are enough for the application.

[belli]

Hi Zach,

Gecko 320/340's have an anti-dither circuit which prevents this hunting when the motor is stationary, I am sure this is what you want.

Greg

[faststeve]

I component of the internal PID filter and stop the singing. However, I don't think you can do that with the Geckos (looks like you have access to Gain [P] and Dampening [D]).

The Gecko is not a true digital PID controller. The analog filter is just a simple low pass filter. Also there is no Intregral component you can adjust. On a low count encoder they should work, but they do sing. Mine did when i tried to use them.
Good luck !