New to Gecko's and having some trouble

[professor]

Hello,

I have a project that I am having problem with.
My friend has a CNC riveting machine that has a dead controller.
So I offered to convert it over to a system using Mach3 as the interface. The machine has brushed Baldor servo motors connected directly to ball screws that have a pitch of 5 turns/inch. The machine has a 75v DC power supply that I was going to use.

I purchased 3 Gecko 230 servo amplifiers, C11 break out board from CNC4PC, encoder AMT102V from DigiKey.
Now for the problems.
The motors jitter when I am jogging the table around then they start loosing position. When the servo does not jitter the movements are dead on. The problem gets worse when I try to get the motors to move faster than 10 ipm.
When powering up the motors jump around for a few seconds. The fault terminal is connected to the Encoder +
Settings:
I have the encoders set up for 250 pulses per revolution.
Mach3 is running at the default kernel speed of 25 KHz.
5000 steps per unit of 1 Inch.
Step is set for Active High (It was suggested that I set up for active low but when I change this setting the motors don't move at all I also tried changing the common to +5V instead of ground.)

I am new to using Geckos so any help will be appreciated.

Thanks,
Paul

[dmauch]

what kind of encoders are you using? Are they the US digital?
If not how long is the cable from the G320 to the encoder? Are your cable shields grounded on one end only?

Dan Mauch
www.camtronics0cnc.com

[professor]

The encoders are from CUI Inc AMT102-V from DigiKey