SDC2160S using Analog Input for speed command

1 year 1 month ago #29534761 by pslawski
I have the SDC2160S drive and I am trying to control a DC motor in Open Loop mode using Analog Input 1 as the Motor Command.
When I apply a small analog command (250mv) to the drive it ramps to Maximum speed very quickly.
It seems like the analog command needs to be scaled somehow but not sure how this would be done.

When I use the Run Console for the RoboRun software to command the motor it works just fine.

Can you tell me if there is some other configuration that needs to be done to scale the Analog Speed command?


Thanks,
Paul Slawski
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1 year 1 month ago #29534763 by LROBBINS
Voltages less than the center value are interpreted as negative motor commands. Assuming max motor command is 1000 (set in configuration tab, MotorOutput/Speed and Acceleration), with center and max set at 4750mA and min set at 0, pulling the pin to 250 mV is approx. 5.3% above 0 and will result in a motor command of -947. It will run at quite high speed. You get a low speed when mV input is near the center value. With your settings, mV input = 4500 will give a motor command of -53.

Scaling is achieved by setting the min, center and max values: min mV is scaled to -1000, center mV is sclaled to 0, max mV is scaled to 1000 (or whatever your maximum motor command is if not 1000). If you want the motor to turn in one direction only, you can set min=0, center=4750/2 = 2375 and max=4750. Input of 2375+250 = 2625 mV will then give a motor command of +53 and inputting 2375-250 = 2350 mV will give a motor command of -53.

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1 year 1 month ago #29534764 by pslawski
Thank you very much, I see how this works now!
I will make the adjustments and try it out shortly.

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