Jerk produced while disabling the axis

[valli]

Hello all,

I have a 7344 Card with a Nu drive amplifier attached to a Velmex stepper motor attached to a bislide axis. Due to some noise problems created by the motor, for scanning in one direction, i have to disable the axis, do data acquistion, enable the axis and move to the next position. when the axis is switched on and off, there is a backward jerk created on the linear motion which is very much undesirable because the position of the axis is changed. I dont use any encoders hence cannot figure how much this backward jerk is. Has anyone encountered such kind of problem. I tried contacting NI and sent emails to the engineers i know , but didnt get any response. I woudl really appreciate if I can get a response to this message.

Thanks
Valli

[Buechsenschuetz]

I think you first should check whether the problem is caused by the 7344 motor controller or the driver.

To check this you should hook up a scope (or a logic analyzer) to the DIR input and, if possible, also to the STEP input of the driver. Usually a driver reverses moving direction only if the level of the DIR input is changed, and if there are still step pulses generated after such a change.

[Dan_Quinn]

Also, if oyu haven't already, upgrade to version 6.1.5 of the FlexMotion driver. We fixed some jerking problems with this upgrade

Dan
National Instruments