Dyn4 analog speed command null adjust?

Is there a way to adjust the zero speed point on the dyn4 drive when running analog command speed servo?

I have 2 servos with brakes and 2 dyn4 drives, being controlled by a +/- 10vdc analog signal with encoder output back to the controller. With servo enabled (using ENA input to disable servo when not being used) and brake disengaged, with a measured 0.009 vdc on the analog input I get drift in one direction. Even if I pull the db25 I/O cable out of the servo drive I still get drift in one direction. I can see the the ballscrew turning slowly and the control is seeing the encoder counts as it shows the drift on the position display. I can not figure out what is causing it, or if there is a way to turn a pot to adjust the null offset to cancel this drift out.

If I'm in RS232 command servo stays put like it should. I have an email into to DMM but of course I wont hear anything till Monday sometime and am trying to get this machine going.

Hello JP.
Did you get this issue figured out?

I also have 4x Dyn4 drives with the 1300w servos (Z-axis servo has brake). They are installed on one of my heavier machines. So, it looks like I am having this same issue on my z-axis. Did you find a fix for this issue?
I'm quite certain it is not noisy wiring issues on my end, I used double shielded individually twisted pair wire with a properly grounded shield. I've tried a few things to get rid of this drift but no fix yet.

I had some issues in regards to the ENA signal being wrongly labeled on pin 3 instead of pin 15 in their manual but I contacted DMM and they fixed this minor issue. Other than this drift issue on my Z-axis, I am pretty impressed with the DYN4 servos, so far.

Thanks,
Rob

Did either of you get the drift worked out? I'm looking to use DMM drives/motors to add another axis to my KFlop/Kanalog setup and looking to command the drives via the KAnalog's +-10v.

Thanks
Greg.

Quote:

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Originally Posted by Greg9504

Did either of you get the drift worked out? I'm looking to use DMM drives/motors to add another axis to my KFlop/Kanalog setup and looking to command the drives via the KAnalog's +-10v.

Thanks
Greg.

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The drift is to do with the control, it has nothing to do with the servo drives, they are seeing voltage from the control if they have drift

Yes I know the drift is because they are seeing the voltage. The original question states that.

I was wondering if there was perhaps a dead band that could be set as 0v is never quite 0v on a DAC. Here's a description from another servo driver:

Quote:

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7.3.3.4 Analog Input Deadband
In analog control mode, even when the input voltage is 0V, it is almost impossible to ensure that the
input voltage is absolutely 0V due to external interference. In some cases, this might cause the motor to
turn slowly in either direction. Therefore, it is recommended that a reasonable deadband value be set to
prevent this issue.

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All analog drives drift somewhat, it should be expected

If the control is set up properly, the drive should not be enabled
until the position feedback loop is active, so you should never see drift

(drift means the drive is enabled but the position feedback loop is not working)