[DDCost]

Hi everyone,

This is my first post on this forum.

Anyway Ive been trying to convert an old IBM SCARA robot for cnc applications. Im using a CNC4PC C1 parallel breakout board with Gecko g320x drives.

Im having a problem that as soon as I supply power to the Gecko drives, the connected motors start turning automatically with NO input step/direction data. Im using the 12v encoders that were originally on the robot and step the signals down to 5V to be read by the Gecko drive. Ive tested the encoder signals with an oscilloscope as well as an arduino to read counts which seem to show the encoders working well.

What could possibly be causing the motors to turn on their own?

Any help would be greatly appreciated! Thanks!

[jfong]

How are you stepping down the encoder signals?

When this happens, usually you need to swap the encoder A and B signal lines. If it is still runaway, the drive isn't reading the encoder signal correctly. Try this

http://www.geckodrive.com/support/ap...-encoders.html

[DDCost]

Thanks for the suggestions. Im using voltage divider circuits to step down the voltage from 12V to 5V. I tried swapping the line, as well as adding resistors, but not luck. Looks like I may have to get different encoders I guess. Just strange cause the signal looks great when viewed on oscilloscope or used with arduino.

[jfong]

Before I would change out the encoders, new ones can be pricy, I would use a level shifter/line driver chip. Spark fun makes one you could try out. Using a voltage divider isn't ideal.

On one of my older motors, encoder wouldn't work right until I played around with switch6. I don't recall which setting I used at the moment.