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Author Topic: Limit Switch Mystery in Mach 3  (Read 1691 times)

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Limit Switch Mystery in Mach 3
« on: September 24, 2017, 11:22:13 AM »
1. I've taken all but one axis out of the picture to isolate my problem. I am using the z axis only.

2. In Motor Outputs, I have z enabled, step pin 6, dir pin 7, dir high active (red x), step low active (green check), step port to 1, dir port to 1.

3. In Input Signals, I have Z++, Z--, Z Home, green checked with port 1 and pin 12 selected for all three. All other options are red x'd. Estop auto-enables and is assigned pin 15 which is wired to ground.

4. In Homing/Limits, nothing is selected, everything is red x'd.

5. Limit switch wires from pin 12 and ground are connected to a normally closed switch.

6. In Settings, the Auto LimitOverRide has green lit LED.

7. The Reset but is not flashing and the z axis will jog up and down at normal speed using page up and page down.

8. Hitting the limit switch triggers the reset button as expected.

9. Resetting allows me to move away from the closed switch but at a slow growling speed and then another fault occurs after only a few steps.

10. Resetting a second time clears the fault and I'm back to normal.

Does anyone know why I'm getting a second fault while moving away from the switch? Thank you for any suggestions.

Offline ger21

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Re: Limit Switch Mystery in Mach 3
« Reply #1 on: September 24, 2017, 12:37:54 PM »
Try increasing your debounce in general config to 2000-3000, and see if it helps.

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JointCAM Dovetail and Box Joint software
Re: Limit Switch Mystery in Mach 3
« Reply #2 on: September 24, 2017, 01:40:30 PM »
Thank you. That worked. This is a new build, so I had no previous performance to judge it by. When I went to the debounce options, both windows were zero. I didn't know in which window to place the 3000 so I tried them both, one at a time and together. The correct choice for me was the top one, Debounce Interval. And now that I knew which one to choose, I was curious to see how it would change if I used a number larger or smaller than 3k. Didn't seem to make any difference, so I left it at 3k for Debounce Index and zero for Index Debounce. It still does one thing that I suspect is normal: after backing away from the switch, it moves at a much slower velocity. If I stop and restart the motion, it resumes its normal speed.