Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: gene8522 on January 21, 2017, 06:51:09 PM
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I'm building a Joe's CNC EVO and have the machine up and running. With the three axis calibrated and running very smooth. But there is a glitch in the probe. I can see the probe light come on and run the probing script like it should, if I hold the probe plate in my hand. If I put the plate down on the work piece, Z goes down and touches the probe plate, the green light comes on and the script stops, the probe light will stay on and the Z will not retract. Then I have to unplug the probe plate in order to get control of the cnc again. I have checked all of the connections on the C-10 BOB. Here is something I've noticed when the probe light is on, pin 1 on the BOB comes on to a relay for the 12v to the spindle cooling pump. Also sometimes the Z stepper will move one or two steps. ???
For a little history, this is my second DIY CNC but I never had problems like this with my probing script. The screenset I'm using is 2010 Screenset.
I have a 104 capacitor on the pins going to the probe.
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Parallel port or motion controller?
What version of Mach3?
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Hi Gerry,
Thanks for the reply and offer to help.
I am using Version R3.043.056.
Gene
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Parallel port or motion controller?
.056, or .066?
Here is something I've noticed when the probe light is on, pin 1 on the BOB comes on to a relay for the 12v to the spindle cooling pump. Also sometimes the Z stepper will move one or two steps.
I didn't read this the first time. It sounds like you may have a serious noise issue?
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Mine is .056
Do you think I should try to get the probe cable away from which wire?
I don't understand why the probe works if I hold the plate in my hand and touch the bit, but not if I put the plate down and let the bit touch the probe plate. As soon as the bit comes in contact with plate and the light come on things stop working. The probe wires are not close at all to the 5v that comes from pin 1 to the relay that turns on the 12v to the spindle cooling pump.
Hope this helps,
Gene
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I would try removing the capacitor and adding a good amount of debounce, just for a test, not permanently.
Does sound like noise.
Could also be a ground loop - when you hold the plate it works but not when the plate is on the machine - this sounds like an interaction between the plate and the machine.
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Debounce does not affect the probe input, if using the parallel port.
For the 3rd time, are you using a parallel port or motion controller?
When other pins are being triggered and the X axis is moving because of the probe input, then I don't think it's the probe wire itself, but rather the probe wire is creating a ground loop somewhere else that's wreaking havoc with your system. It would appear that this is freezing Mach3.
I don't understand why the probe works if I hold the plate in my hand and touch the bit, but not if I put the plate down and let the bit touch the probe plate.
Once you set the plate on the machine, it's causing a ground loop to be created. The fact that your X axis is moving means that it's very bad. Are you using shielded wire for anything? Are you using Star grounding? You may have multiple problem areas and the probe is just part of the issue.
When the probing stops at the plate, and won't move, is there a message displayed in the status bar? There should be some probing messages. What's the last one displayed?
Also, if the probing macro (or any other macro) does not finish, you MUST restart Mach3, or you could get strange results moving forward.
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Gerry Sorry I didn't pick-up on the 'parallel port or motion controller' question.
I use the DB25 parallel port.
Gene
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Well good news....... I think I may have identified my problem. I had read that there is no wire inside the Chinese spindle motor for a ground and that they thought that they should put one in. So I did also. But I found that since this CNC is all metal everything is grounded inside the VFD. Which turns out not to be good. It causes strange things to happen to the ground on the C10 BOB if you touch the probe plate to the bit. After I disconnected the ground inside the VFD everything (well almost everything) works normally. If I do a Z zero for a single tool the Z axis comes down touches the probe plate (probe active light lights) and retracts to 1.5" normally. But if I do a Z zero tool change probe the script will only run the bit down about 1/4" (not even close to the touch plate and the probe active light does not come on) and retract about 1/8" down 1/4" and retract up 1.5". I never changed the script for the Z zero so what's happening?
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Noise is triggering the probe input. It happens so fast that you don't see the LED light up. You have some grounding issues on your machine which are causing all of the problems.
A capacitor across the probe input may help with that.
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Sometimes the bit will not touch the probe plate when doing a single Z zero and the probe active does not come on????????
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OK I have it running ...... I wasn't sure how important the 104 capacitor on the C10 BOB between the pins on the probe were and I had removed it. Now I know that having the capacitor in place is very important. I reinstalled the capacitor and the probing works as advertised. What a relief I now have a fully functioning Joe's EVO CNC Router!!!! And just in time too. I received an order for a plaque this morning. Gerry thank you for your help. Without these forums I would never have been able to build my two CNCs.
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Sometimes the bit will not touch the probe plate when doing a single Z zero and the probe active does not come on????????
It happens so fat that you don't see it.
The capacitor is a bandaid for a noise problem. Most people don't need or use them, but in some cases, it's a much easier fix than solving all of the noise issues.