ohmic sensor

[kennye]

I am trying to upgrade my table with a ohmic sensor I've encountered a couple problems since I installed it .I used a water switch that someone had posted on this site about I have everything wired and that seems to be good my problem is whenI try a cut sometimes it cut stops at 0.0795 always and stops cutting I can restart it and sometimes it cuts all the way through. I noticed on mach 3 it says probe ignore activated at call for probe and when it does start its not setting the right cut height Im thinking that its all related maybe not. if some one could tell me what I screwed up I would appreciate it .This thing is driving me crazy thanks in advance .

[acourtjester]

In the G-code are you using the G28 command or the G31 command for the Z axis movement. They operate the same but one is looking for a home switch input and the other is for a probe input to the BOB board.
Probe post processor
post.ModalText (" G31 Z-50 F10\n")
post.ModalText (" G92 Z0\n")
post.ModalText (" G0 z0.16\n")

probe3.jpg (8.33 KiB) Viewed 2629 times

probe3.jpg (8.33 KiB) Viewed 2629 times

Homing post processor
post.ModalText ("\n G90F30\n")
post.ModalText (" G28.1 Z0.50\n")
post.ModalText (" G92 Z0\n")

probe 4.jpg (6.8 KiB) Viewed 2629 times

probe 4.jpg (6.8 KiB) Viewed 2629 times

[kennye]

I have the G31 code iM Im working with so the probe should be checked ?

[acourtjester]

Yes and the wiring should be hooked to the pin in Mach3 you selected for probe input.

[kennye]

I think I have everything wired right the problem. Im having now is when I start the cut the torch moves to the position to start and then it goes down touches the plate and goes up to what it looks like the desired height then it starts back down .Are the settings any different in the tool in sheetcam or do I have another problem?

[acourtjester]

It sounds like you are not firing the torch, The G-code should get you to a point where the torch is at pierce height (which is sounds like it is) then re the torch. then after a pierce delay drop down and start moving with the cutting operation.Attached is a G-code showing the steps they may not be exactly the same but should have these actions in it to work. From steps N0110 to N0200 gets the torch in position to light step N0210 is lighting the torch. N0220 is pierce delay N0230 is torch drop to cutting height and N0250 is start of moving the torch for cutting action of the job.
N0170 is floating switch correct distance (before I installed the ohmic sensor) N0180 is to set Z DRO to 0.0" N0200 is not needed just happened to be in the G-code I picked for an example.

pierce.jpg (45.37 KiB) Viewed 2583 times

pierce.jpg (45.37 KiB) Viewed 2583 times

[kennye]

Thanks Ill look I do know the files I converted to DXF do have a mo3 and mo5 cant remember what order the other codes were
but Ill look and let you know. What you posted will be a big help thanks

[kennye]

Sorry its taken so long to get back .I had to wait on a ohmic nozzle for my plasma and then we got snow and everyone knows in the south when we get snow the world stops turning .took forever to get it and when I did someone put a cola on my control and turned it over and had to replace a couple of drivers . So I been real busy . The problem Im having now its stopping and mach is freezing up untill I hit stop and cycle to get it going again it doesnt do it on every cut but when it does it might put the z axis on like 00795 no matter where I start it at 90% of the time thats the way it stops
and if I start another cut it may be 01201 doesnt make any sense to me could it be in the post processor Im using or something Im missing
or is my shop haunted ? ps it was doing this before the cola episode too thanks for any help .

[acourtjester]

To better understand you situation, had the table run without problems before and you are just trying to upgrade with a ohmic sensor?
After you had the cola disaster did you change to a different BOB card or switch the post processor. Post processors are very connected to the electronics used and will generate G-codes to correlate with their circuits. Are you able to look at the G-code and see what it is doing a table should follow what the G-code is telling it to do. If you G-code has an M0 it will stop at that time until the cycle start is pushed again to start from there.
Mach screen shows the G-code lines as it does its work so you should be able to see where it stops and then know what it is doing.

[kennye]

Its something to do with the probe mach3 is telling me probe ignore activation at start up I dont know
what it is telling me .I know it freezes up in the middle of a cut .Would the probe be the plasma trigger or in the plasma
itself ? Everything is checked in config like u pointed out .I think if I could figure that out this would help end my journey .lol

[sphurley]

What system do you have for the movement of the motors? Gecko or a complete controller?
Mach does it thing based on the G-code that you created. How are you creating the G-code? What post processor are you using?
The controller should have a relay that Mach activates based on the G-code to fire the torch. You should then have a feedback circuit from the plasma sometimes known as ARC OK that tell Mach that the torch has fired and to begin movement. If you loose the ARC OK signal the movement should stop.

[acourtjester]

Look in the Ports and pins input list and see if you have the probe enbled, if not mach should not be looking for the probe. This is a function to signal when something has touched, in plasma it is the tip of the torch to the metal. It is also used on router tables to signal the top of the material for setting the bit height. This only happens when the probe has be enabled and the G-code has commands to do a probing action.
This command is G31 for the Z axis. Now if you have the probe enabled but no command then it may be noise that triggers Mach to give that message.
since it happens while it is cutting I would say noise, check the probe enable in mach see attached.

[kennye]

Yes I have it enabled I have the right post processor it is the one I got from you that says mod by tom the codes seem to be as they should. I dont understand about noise how do I look for that or fix it ? in the meantime I think Ill change the gecko board that is the only thing I haven't changed and I have a spare. I will keep you posted thanks in advance.

[kennye]

Is there something that should be changed in router config or has nothing to do with it ?

[acourtjester]

Well I have no experience with Gecko boards so I cannot be sure about the Post processor that I sent you. Post processors are written to work with the electronics controlling the table. The info I have given you may not be compatible with your electronics. You will need someone that uses Gecko board to tell you which post processor to use.

[kennye]

Thanks may be someone will chime in on this issue

[kennye]

I have noticed that every time a code with 1200 comes up it will stop example n24420 zo 1200
or n2260 zo. 1200 anytime the z axis is coming up and lands on a code with 1200 attached to it it freezes and and the height on mach is showing +1201 if that makes any sense .Thanks in advance

[tcaudle]

something looks hinky with that code. There should be no spaces in the number . it should show Z0.120 (or Z0.1200 if you are running 4 places. so this is acceptable Z0.120 or Z 0.120. Has to be a zero not an o. and no spaces.in the number itself