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SLAVE AXIS PROBLEM
« on: January 01, 2012, 06:36:42 AM »
I have a machine with two slave steppers on the main axis.
I have slaved X and A and installed home switches on both.
I have set the A axis to linear.
Using manual control the pair of slaved axis move OK and remain in step but:

1.  When I use to 'Go to Zero' command, the axis remain in step but move in 'bursts' of about one second/30mm.
2.  When  using 'REF ALL HOME' the Z and Y axis do the correct thing (touch the home switchs and then back off) but the X and A axis do odd things - one touches/backs-off, the other touches,reverses and keeps going in the wrong direction.

I have very carefully checked:
1. Pulse rate and varied it from 25KHz to 100KHz and it makes no difference.
2. All the ACHIVE_HIGH/LOW, DIRECTIONS, PINS and PORTS.

Any help would be very welcome.

Regards Bill Legge

Offline ger21

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Re: SLAVE AXIS PROBLEM
« Reply #1 on: January 01, 2012, 07:51:41 AM »
Do you have "Home Slave with Master" Unchecked in General Config?

Are both axis Homing Speed the same in Config > Homing/Limits?

Can you post your homing script, and your .xml file?
To get the homing script, go to Operator > Edit Button Script and click the ref all button
Gerry

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Re: SLAVE AXIS PROBLEM
« Reply #2 on: January 01, 2012, 05:22:48 PM »
ger21

Thank you.  I had not spotted the 'HOME SLAVE WITH MASTER' check in the General Config.  That must be my problem; I'm very grateful as I was almost giving up and going to spend a long time re-building to use a single stepper.

Any ideas about why the 'GO TO ZERO' causes 'jerky motion' on the pair of slaved axes?  A few notes:

1.  The jerkiness only occurs on the slaved pair of steppers.
2.  I've tried uncoupling the motors from the machine in case it was excessive mechanical stress - but it makes no difference.
3.  The slaved pair run smoothly/easily under manual controll (using the 'HOT KEYS') - so it would not seem to be driver/power supply problems.

What on earth could be the difference between HOT KEY/MANUAL control and GO-TO-ZERO ?

The only slightly unusual thing is that I'm using a lap-top pc - but it's an old one and has a proper printer port.  Could the lap-top be running out of processing power; but then why would the manual mode work OK?

Regards Bill Legge