Motion Control Problem with Servo Amp

[parkerbender]

Okay, I decided to move this to the forums, as to quit spamming the heck out of Bloke's PM-box (sorry!) and also so someone can be helped if they have the same problem.

I have a problem where when I put power to the servo drives, my x-axis takes off about an inch and a half, then faults out the drive. The encoder reads correctly when I turn the ballscrew by hand.

Here are the clues:
If you switch the A+ to B+, B+ to A+, A- to B-, and B- to A-, the x axis runs correctly, but in reverse. (when you hit the + jog it goes in a - direction)

When the encoder is correctly wired, and the three plugs are in the original Max400 drive, the table jumps to the right (negative in cartesian coordinates) for an inch or two, then faults the 'X-axis Servo Amp' when the start button is pressed upon startup to power the drives

When the encoder is correctly wired, and the three plugs are in the Y-axis Max400 drive, the table jumps to the left (positive in cartesian coordinates) for an inch or two, then faults the 'X-axis Servo Amp' when the start button is pressed upon startup to power the drives

When the encoder is wired up with A and B swapped, so you can give power to the drives without faulting out, the Y and Z axis both work correctly.

Given these symptoms, what might a person think that it can be?

[Al_The_Man]

Is this something that just occurred or a recent system hook up?
If I decipher your post right, if you reverse the phasing of the X axis it runs OK, but the indicated direction is wrong, if so, then you have the phasing between the encoder and the command signal reversed, which means they BOTH have to be reversed OR, if the control allows it, once it is running without fault, reverse the axis direction by setting or parameter?
What control is this?
BTW, if you want to swap the encoder phasing, you can do it by just reversing the A & A- OR the B and B-.
Al.

[parkerbender]

the backstory:
firstly, thisis a '91 hurco 40slv, with ultimax 2 controls.

this machine has been giving me a servo amp error upon startup for probably a couple months, off and on. it will also give me a z fault when i would switch from auto or manual toolchanger control.

more and more i would begin to get z, x, and i think there was even one y axis fault, during programming, though running 30-40 hour weeks i think there were only maybe one or two faults during a running program.

last tuesday when i started the machine, it started jittering on the x when calibrating. it faulted out. i then jogged the x back and forth to see if it would go away... it did, but jittered realllly badly for 10-15 seconds firs

i had previously seen green sea creatures growing in the junction box on the x servo, so i decided i would clean things all up, take the connectors apart, and if i couuldn't get it back together, i'd just solder and heat shrink it.

when i got it back together it began this problem started, i originally thought i screwed up the encoder wiring, re-wired it half a dozen times until i finally traced the wires back to the board. i've swapped encoders and amps between axis, to no avail.

and here we are...

[powerr]

Could have a bad DSP board. i have seen them cause jitters and runaways. i don't know if the servos will power up if you disconnect the x axis plug from the dsp board. have you tried swaping the x and y axis plugs on the dsp board see if it goes away.

[judleroy]

Check that you dont have a stuck limit switch. This caused a similar problem for me in the past.
Judleroy

[parkerbender]

New development...

I swapped the power wires, and the tach wires, and now the X works, but if it gets to the limit switch, it freezes the axis, and won't move it anymore. if you manually back it off by turning the screw, it takes off away from the limit switch for about five inches once it's off the switch. (scary as hell the first time it happens, with your hand in there!!!)

The machine says 'Axis Not Calibrated - Marker Not Found On X' Though, it shows an X- flag on the screen, and touching the limit switch stops the travel, though it doesn't stop it immediately like on the other axis, it coasts a little bit...

Anyway, what would be doing that?

[judleroy]

If the limit is the same as my machine it is in the middle of the table and is also the home. You can take it off and clean it up and degreaser it. Make sure it does not stay stuck in. When this happened to me it would read the same axis not calibrated error.
Good luck.
Judleroy

[parkerbender]

It is the same where the switches are in the middle, but unllike it' ssupposed to, when it hits the limit switch, it doesn't stop, and back off a little. It coasts to a stop, about .650 past where it should have tripped the switch...

[bloke]

Parker, this is just as I suspected. I've tried to find the old jumper settings for the first series of dual axis cards but to no avail so far.
If you have the axis working like this, swapping the actuator flags for the X axis should stop the axis in the right direction and allow it to change direction as well.

I know it's not the ideal way of sorting your problem but it'll get you going for now.
I'm going to keep looking for the jumper settings.