X axis servo switches from dispalcement to velocity based control

I have standard 4 xis mill using servos with encoders on the x/y/z axis and a stepper on the fourth axis. This is the second time that he x axis control has suddenly changed from a displacement to a velocity based mode.

In the middle of running a test problem, suddenly I started getting following errors on the x axis. When I switched to the mpg to move the x-axis, every click on the mpg would change the velocity of the x axis, not the position. One click on the mpg, which equates to an increase of one on the encoder, and the x axis would move at 0.01 ips. Two clicks and the x axis would move at 0.02 ips. Somehow the x axis has changed from increments on the encoder equating to position to increments on the encoder equating to velocity changes on the x axis.

I have searched the various pin values and can not find any flag or signal that would change the x axis encoders from operating in a displacement based format to a velocity based format. Anyone have any idea what would change the x axis response to changes on the encoder from dispalcement to velocity?

Thanks.

That's pretty bizarre...

Can you post your hal an ini files here?

I did additional troubleshooting and determined that when the x axis apparently switched to a velocity mode linuxcnc was no longer getting input-A or input-B signals from the x axis encoder. To determine if loss of the encoder signals was the cause of this problem, I switched encoder x and y to see if the problem would occur on the y axis. Since switching the encoder signals, the problem has not re-occurred. It may have been a loose connection with the encoder wiring that caused the loss of encoder x signals and that may have been what caused the apparent shift in the axis behavior.