Motor Losing Steps

[toolwatchers]

I'm having trouble with an Oriental stepping motor, the PK299DAA. Check out the following video:

http://www.youtube.com/watch?v=p5FhqNkSIJQ

We are using this motor to move a microscope at the end of an arm. We ran an experiment to see how accurate the motor would be. We attached a square pattern to the rod in the video and took a photo of it with the microscope each time the motor was moved. As you can see in the video, we have lost some steps as the arm moving process is repeated.

Can someone tell me why this is occurring? We need this motor to be very accurate, since one lost step means that the microscope will be out of focus.

We have tried adjusting the current, speed, and step size to no avail.

Thanks,

Jeremy

[omsupport1]

Jeremy,

Thanks for using Oriental Motor products!

From your video, it appears that the load inertia is too large for the motor. I say this because of the "Shaking" that is occuring during the motion. The motor is probably missing steps during this "shaking" period.

To fix your problem:
-Can you tell me what the load inertia value is?
-Can you reduce the weight of the assembly in any way?
-Using a gearhead is another way to reduce he reflected inertia to the motor shaft. Is using a gearhead possible?

Do you know how many steps you are missing and is the number of missed steps repeatable?
What are you using as a controller (pulse generator)?

We will be happy to work with you on this issue via telephone, if you would like. Please send an email to: forum@orientalmotor.com with your contact information and we will contact you ASAP.

I hope that this helps.

Thanks!

OM Support