everything is up to date and its still just ramming the head into the metal and dragging it around…
according to the THC test its says its reading 95.4V, so i went and set the voltage to that and its still just ramming the head into the metal and dragging it around
have you tried it with THC off to rule that out? IHS should still work.
yes, when i turn the THC off, it runs just fine.
i dont get it…
Can you post a pic of how you have the THC box connected?
i have it wired up like this thread.
when i said it works (in that thread), i meant it didnt conflict with anything. its never really worked right.
the red wire from the VIM box goes to the ground clamp lug inside the machine.
the black wire from the VIM box goes to the torch leads inside the box.
i tried to upload pic but its saying theyre too large
nvm got it to upload finally
how is the lil black THC box connected?
Black wire goes into torch plug, red wire goes into Clamp plug.
Cable to the machine is plugged into raw voltage plug.
Unfortunately, presumably to keep the cost down, Langmuir really did not use enough galvanic isolation in the controller. For this reason it is highly susceptible to grounding problems which are particularly hard to avoid given the presence of the water table. Ideally, the IHS wiring would be galvanically isolated from the control board (easily done with an opto isolator, but requires an additional isolated power supply ($)) and the voltage sense would also be isolated from the controller (less easily done, but can be accomplished with a voltage to frequency converter, opto isolator and another isolated power supply ($$$)). Doing it right, might add $100 to $150 to the cost of the controller, which is significant considering the cost of the Crossfires, but would probably be worth it to anyone who really wants THC.
so, basically theres nothing LS can do about my problem. starting to get real bored with chasing the metal around holding it down so the head doesnt hit the metal from it rising.
working with a lot of .090 aluminum right now and it loves to rise.
Unless you actually have a faulty component, probably not assuming you’ve carefully followed Langmire’s detailed THC troubleshooting instructions. One might hope, given the significant level of issues reported on this forum, that Langmire might reengineer the control system to incorporate proper isolation. While clearly some people get the system to work as it is, it is really not a robust system.
given also the number of systems sold there are not any problems is the other side of looking at it…
sure there may be some problems…but you will always hear from people with problems…and never hear from people who have perfect running machines…
I would agree with you except for the fact that because of the lack of proper galvanic isolation, the problems many are experiencing are hardly a surprise.
To design a system which requires the work piece and control computer not share a common ground is simply asking for trouble. There are also potential safety issues with everything floating wrt. ground.
For my part, I will not buy a THC from Langmuir but will build my own and do it right.
you are a lucky person to be that experienced and have that knowledge base to take that on.
Is there a way to tap into and make a common ground between the two things you mentioned?
any LS tech guys want to have a stab at it?
Not if you want the THC to work. The problem is the torch runs negative with respect to the work piece. The THC can only measure positive voltages with respect to its ground (which is also the PC ground because of the USB connection). Thus, the torch voltage sense is connected to THC ground and the workpiece sense is connected to the THC ADC input. Because of the way the voltage divider works, this puts the workpiece a few volts above THC/PC ground potential. Anything which provides any kind of ohmic connection between the THC/PC ground and the workpiece will disturb the voltage sensed by the THC and result in erratic behavior of the THC.
Because it is difficult to ensure the workpiece and water table have no stray connections to ground, you will see in Langmuir’s trouble shooting guide that they suggest running only with a laptop and running off batteries if you have issues. This should ensure there is no connection between THC/PC ground and any other grounds although if your laptop has a metal case there is a possibility that touching it could cause problems.