Feed rate difference on x axis by factor of 10

I have a Tree 325 3 axis mill using dc servos . My Linux hardware consists of Mesa 5i25 Superport PCI card and a Mesa 7i77 breakout card. I have been tuning the X and Y axis. The Y axis travels the correct distance in the correct time. However X axis travels the correct distance in the correct time in the positive direction but travels at 1/10 the speed in the negative direction but final travels the correct distance. These travel commands are being issued via the MDI interface. such as G1 F10 X1. Additionally when X axis is moving the Feed rate shows on the jog slide bar (AXIS GUI) 1000 in/min for X+ and .1 in/min for X-. There is no such jog display for the movements of the Y axis. I assume I must have a corrupted file in the Linux install.

Tree_325 wrote: Additionally when X axis is moving the Feed rate shows on the jog slide bar (AXIS GUI) 1000 in/min for X+ and .1 in/min for X-. There is no such jog display for the movements of the Y axis

The jog slide bar doesn't normally move unless you move it.

Can you confirm that the slider is moving spontaneously?

Is adaptive feed enabled perhaps? (and connected wrongly).

I was incorrect it is the Maximum velocity slider that moves. I ask for 10 in/min I get the slider showing 1200in/min in the positive direction and .1 in/min in the negative direction. I have removed the toothed belts from both x and y axis so the load on the motors should be very similar. I believe that axis driver boards are set up for constant velocity. The motors have an index signal and quadrature signals from the encoder to the input on the 7i77 board. They also have a analog tach signal to the driver board and of course DC drive voltage to the motors. Your comments raised a question I hadn't consider. My x axis moves in the opposite direction as predicted by linuxcnc. The t ach wiring and the drive wiring are matched correctly but the encoder might be in conflict. I guess I should try reversing both the tach and drive orientation and test again.

If it is moving significantly more slowly than requested I would expect a following-error trip.

What are your f-error limits set to?

If the f-error limits are not excessively large and are not tripping then that suggests that the axes are being commanded to move more slowly in one direction than the other.

I wonder if there is a possibility that this is due to velocity feedforward (FF1) and encoder (Pgain) feedback working in opposition?

I tried reversing the Tach and Drive wires on the X axis. So now when the command G1 F10 X1 is given the GUI has X going more negative so I need to change that back. These are my current settings from the ini file

FERROR = 10.005
MIN_FERROR =0.1005
P= 1.0
I = 0.0
D = 0.0
FF0 = 0.0
FF1 = 0.0
FF2 = 0.0

I have tried changing Servo Dynamics axis driver boards with the Z axis but the results remain the same. I have also measured the comand voltage from the Mesa 7i77 to the Servo Dynamics board. The voltage starts at a level similar to the level when X is traveling positive but after X moves about -0.200 the level drops back to -0.030 v and stays there until the move is complete. The Servo Dynamics boards have a trim pot for boosting the travel speed of an axis , the "Signal Level Pot"

Tree_325 wrote: The voltage starts at a level similar to the level when X is traveling positive but after X moves about -0.200 the level drops back to -0.030 v and stays there until the move is complete.

That's good info, it means that the problem is in some way inside LinuxCNC.

What happens if you Halscope the output of the PID and the input to the DAC? Is that reducing too, if not, then it's something strange in the 7i77.

Can you post your hal and ini files?

Let see if I can get those posted

Enclosed Files

I have, as another solution, downloaded burned an image for Linuxcnc 2,7. I have a spare computer and hard drive to install it on.I would have to reuse the Mesa cards. Could I copy over the Hal and Ini files and reuse them?