Crusader II retrofit

Punking
I reversed the ENA1 and COM wires to Y and now its stable.
Tried the configure page and using the the "test", "refresh" feature changed the P value from its starting point of 50 down to Zero with no change in the X axis creep. Seems to be moving about the same speed it was dithering at before but now just in the x plus direction.

Jim

Why would you reverse the ENA1 and COM wires if you do not have a problem with drive enables?

And please do not try and reverse the analog output polarity by switching the AOUT and COM wires,
this can damage the 7I77 as this will short out the 7I77s analog outputs (If you do not have a differential input drive)

As I mentioned before, if the feedback is wrong (you get a runaway) you reverse the analog output polarity
by changing the sign of the OUTPUT_SCALE parameter in the .ini file

PCW

Stupidity mostly. Wires on Y back in original position and Y axis runaway is back.
What did you mean " Likely means you need to reverse the analog out sign on Y" and where do I change it?

Thanks for your help
Jim

The OUTPUT_SCALE parameter for Y (probably called AXIS_1) in the .INI file

That is (in the AXIS_1 section of the .ini file ) change

OUTPUT_SCALE = 10.0
to
OUTPUT_SCALE = -10.0

Y axis is now stable and jogs in both directions. Same for Z axis. But X is continuing its slow drift in the plus direction.

When trying to jog X I get "cannot unhome while moving. joint 0" and "joint 0 following error" errors. But the axis doesn't move under the jog command.
After 10 min X's drift will reach the .5 following error value and kick out an error.

Jim

Sounds like either the X channel analog out is:

Disconnected

Reversed (AOUT0 and GND swapped at drive) shorting out AOUT0 and grounding the drives analog input

or the X P term is 0

If you mean the P value in the ini file it is P=50

I'll double check the wiring and connection on TB5 DRV0.

YES
Reseated all wires in TB5 DRV0 and now X is responding. It jogs and holds position with the .0004 dither. X's dither is noticeably quicker then Y's.

Jim

DIther rate depends on the 7I77s and Drives offset voltage at 0 velocity command
Drives usually have a potentiometer to adjust this with.

Next step is tuning:

gnipsel.com/linuxcnc/tuning/servo.html

Please stick with adjusting the settings in linuxCNC at this point.

I would not recommend adjusting the west amp amplifiers. Those amplifiers are a black hole of historasis . I asked jambly if the system was smooth before he started the conversion, he said they worked fine.
I started adjusting my we stamp amplifiers in my conversion. I ended up using an old ocilloscope to rough in my settings, then I was able to get ohm settings for the six pot circuits on the amos from a retired anilam repairman. I removed each amp and bench tuned the amps with an ohm meter and beads of sweat.
Never. Again. Those are an abyss I recommend staying out of . ; )
The link PCW gave is good to start with.
Wikipedia has good resources to learn about pid tuning.
Andy paugh had a great post here about pid tuning related to a cars cruise control.