Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: Bill Legge on January 01, 2012, 06:36:42 AM
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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
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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
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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