Issue with Z axis driving down and tripping

[Rickzink]

Im hoping someone can assist me here. I am getting frustrated with this dang table.

My Z axis drives down so far that it trips the E switch. There doesn't seem to be a rhyme or reason for it. It will start cutting, cut for a distance and then it will drive down and trip E-switch. My feather touch yellow light comes on to sense the surface of the metal but it still trips out. I have tried a few different files and it does the same thing. I can select the starting point for another portion of the cut, and it will start cutting just fine but at some point it will trip the E-switch again.

Can someone point me in the right direction on this? I have a full head of hair, but if this keeps up my poor wife is going to be married to a bald man from me pulling it out!!!

[TJS]

What Z car are you using. I had a very similar issue with my PPLC Z car. It was losing steps because of the way it was designed. There is a plastic type "nut" that was slipping past it's stop. The stop is just the head of the socket head cap screw edge (very poor design). I shimmed up the socket head cap screw for now but I plan on making a brass type nut. Take a good look at your Z car.

[weldguy]

Good info above from TJS.

So your seeing the feather touch light come on indicating it has sensed the surface but the z continues to drive down until the z limit is tripped?

[Rickzink]

Good info above from TJS.

So your seeing the feather touch light come on indicating it has sensed the surface but the z continues to drive down until the z limit is tripped?

That is correct. It senses but continues to drive down.

[tcaudle]

First of all the touch off (via ohmic sense ) is not and estop. its ignored when the system is not in a PROBE move (G38.2) So if its diving down and hittin g the metal during a cut the touch off is no going to do anything. If you have a floating torch holder and the Z home is acting as backup for the Ohmic then you have the option of making the Z home ALSO a Limit. That will stop your motion if it trips. In homing or touch off it still acts as a home swtich and as backup for the ohmic .

What needs to be drone is to discover WHY your torch is diving during a cut. Torch dive with the DTHC enabled for only one reason: The voltage is spiking for some reason. If you do not have VAD on and you go inot a corner or tight turn then the voltage will rise as the feedrate slows down. VAD will sense that feedarte slowdown and lock the Z ....this is if you have not defeated VAD by setting it at the wrong numbers . In older If you manually change the feedrate using the FRO on older Commandcnc it will confuse VAD and cause itto not work.

If you lose voltage from the RS485 cutting out the torch CLIMBS. If your PWM quits sending the thorch CLIMBS.

SOmtimes NOise can cause the ssystem to see more voltage than the PWM is sending and THAT could cause the DIVE but more than likely the voltage spike is from motion or the cut . Cutting too close to a void will cause voltage spikes. Not using the END of CUT RUle in SHeetCAm to turn the DTHC off Before the end of the cut causing diving at the end as the cut comes around to crsoo the beginning .

Running some test cuts iwith DTHC in MANUAL mode and OFF on falt material will let you monitor the Torch Volts and see if its spiking and when.

You can get more precise help on our Support Forum.

BTW if you are trying to control the DTHC with Cut Rules it will cause problems. VAD and a cut ruel will fight each other. the ONLY Cut rule you should use is the End of CUt (Before End ) .

[Rickzink]

First of all the touch off (via ohmic sense ) is not and estop. its ignored when the system is not in a PROBE move (G38.2) So if its diving down and hittin g the metal during a cut the touch off is no going to do anything. If you have a floating torch holder and the Z home is acting as backup for the Ohmic then you have the option of making the Z home ALSO a Limit. That will stop your motion if it trips. In homing or touch off it still acts as a home swtich and as backup for the ohmic .

What needs to be drone is to discover WHY your torch is diving during a cut. Torch dive with the DTHC enabled for only one reason: The voltage is spiking for some reason. If you do not have VAD on and you go inot a corner or tight turn then the voltage will rise as the feedrate slows down. VAD will sense that feedarte slowdown and lock the Z ....this is if you have not defeated VAD by setting it at the wrong numbers . In older If you manually change the feedrate using the FRO on older Commandcnc it will confuse VAD and cause itto not work.

If you lose voltage from the RS485 cutting out the torch CLIMBS. If your PWM quits sending the thorch CLIMBS.

SOmtimes NOise can cause the ssystem to see more voltage than the PWM is sending and THAT could cause the DIVE but more than likely the voltage spike is from motion or the cut . Cutting too close to a void will cause voltage spikes. Not using the END of CUT RUle in SHeetCAm to turn the DTHC off Before the end of the cut causing diving at the end as the cut comes around to crsoo the beginning .

Running some test cuts iwith DTHC in MANUAL mode and OFF on falt material will let you monitor the Torch Volts and see if its spiking and when.

You can get more precise help on our Support Forum.

BTW if you are trying to control the DTHC with Cut Rules it will cause problems. VAD and a cut ruel will fight each other. the ONLY Cut rule you should use is the End of CUt (Before End ) .

Thanks for the guidance!!! I may have miscommunicated. I am aware the the touch off is not and estop however, I have a limit switch attached to my 'Z" axis that also severs as an estop. when it drives down, it does so even though it sensed the material.

I am going to test it again this morning noting the voltage to see if it is jumping. I am not sure what VAD is. Please keep in mind I am fairly new to this world and have essentially just figured things out on my own. No formal training or education. Although, this site has been a HUGE source of knowledge and assistance.

[Rickzink]

OK.....after playing with it some more.....I am still having the same issue. As it has been doing, I pulled up a couple of different files I have cut successfully in the past. Its doing the same thing. On one of the files, I got within 8" of completing the cut and the torch dove into my material and tripped the E-Stop. I noted absolutely zero voltage rise. I disabled the DHTC and this had zero effect. I have no cut rules in any of these files I am cutting.

I dont understand why this is happening. I was cutting the other day without any issues and just all of a sudden, without any known changes, this has started happening.

More guidance please.

[tcaudle]

Go to our support forum if you want detailed support . Virtually no one is "formally" trained on using these systems.
If Cutting with the DTHC OFF should cause the Z to freeze. its not getting any motion from the DTHC and it SHOULD not be getting any motion form G-code.

[Rickzink]

Go to our support forum if you want detailed support . Virtually no one is "formally" trained on using these systems.
If Cutting with the DTHC OFF should cause the Z to freeze. its not getting any motion from the DTHC and it SHOULD not be getting any motion form G-code.

I'm trying to get access.

[tcaudle]

There are no pending requests for the Support Forum. Several new members last few days

[Rickzink]

There are no pending requests for the Support Forum. Several new members last few days

I know. I am trying to get access to my account but have not had a response to my request as of yet. I am already a member but cannot locate my username. I can oddly enough reset my password but cannot dig up my username for the site. I just submitted a request via the contact us option. Hopefully, they can asist.

[tcaudle]

If you don't know your user name then the only other way to find the account and reset the password is via the sign up email you used.

[Rox]

First of all the touch off (via ohmic sense ) is not and estop. its ignored when the system is not in a PROBE move (G38.2) So if its diving down and hittin g the metal during a cut the touch off is no going to do anything. If you have a floating torch holder and the Z home is acting as backup for the Ohmic then you have the option of making the Z home ALSO a Limit. That will stop your motion if it trips. In homing or touch off it still acts as a home swtich and as backup for the ohmic .

What needs to be drone is to discover WHY your torch is diving during a cut. Torch dive with the DTHC enabled for only one reason: The voltage is spiking for some reason. If you do not have VAD on and you go inot a corner or tight turn then the voltage will rise as the feedrate slows down. VAD will sense that feedarte slowdown and lock the Z ....this is if you have not defeated VAD by setting it at the wrong numbers . In older If you manually change the feedrate using the FRO on older Commandcnc it will confuse VAD and cause itto not work.

If you lose voltage from the RS485 cutting out the torch CLIMBS. If your PWM quits sending the thorch CLIMBS.

SOmtimes NOise can cause the ssystem to see more voltage than the PWM is sending and THAT could cause the DIVE but more than likely the voltage spike is from motion or the cut . Cutting too close to a void will cause voltage spikes. Not using the END of CUT RUle in SHeetCAm to turn the DTHC off Before the end of the cut causing diving at the end as the cut comes around to crsoo the beginning .

Running some test cuts iwith DTHC in MANUAL mode and OFF on falt material will let you monitor the Torch Volts and see if its spiking and when.

You can get more precise help on our Support Forum.

BTW if you are trying to control the DTHC with Cut Rules it will cause problems. VAD and a cut ruel will fight each other. the ONLY Cut rule you should use is the End of CUt (Before End ) .

HI-
could send a picture of your end of cut rule?

Im new to this CNC Plasma. I read so many thing saying add the HOLE rule etc. I added them. Things were fine for a while. But now I am having issues with torch diving. Also torch stops after a circle occasionally. I read your comment about VAD a the ATHC. Basically I don't need the rules to slow and turn the THC off and then back on, IF the VAD is engaged?

A few fixes before todays current issue of diving. Cables loose to the THC box/computer. Bad ground another time. Also seems to happen with Canadian steel.

Appreciate all the information shared here! Thanks
Roxy Parent
Peacemaker Grills

[tcaudle]

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