I have a Hynde cut 60 with a machine torch. Sometimes it will pierce and then just quits cutting. If I unplug the laptop charger it works great.
I think I remember a post sometime ago someone was having problems with stray voltage or something.
The thc is around 100+ volts when its working properly but only 10 or 14 when it doesn’t cut.
Do I need to ground the table to a ground ground?
Many people it is called a ground loop. Easiest fix is to run on battery or use a ground eliminating plug. A loop from the plasma comes back from the plasma through the earth ground.
You can search ground loop and probably fine dozens of threads.
Thanks. I believe I have read that before but old mind can’t remember crap
My first plasma was a rw45 it would do it on occasion. I upgraded to a hypertherm it freezes fire control as soon as arc starts .
Haha, as usual @Phillipw beat me to answering your question! But yes, he’s exactly right. If the issue persists after trying these steps reach out to us at support@langmuirsystems.com
Computer charger have a grounded plug? If it does get yourself one of these.
LYOOWNG (3 Pack) 3-Prong to 2-Prong Adapter Grounding Converter Polarized 3 Pin to 2 Pin Power for Wall Outlets Plugs, Grey Amazon.com
Put one on the charger and one on the Langmuir controlbox plug.
Grounding the table is a good idea, but in this case, that should take care of it.
Grounding the table requires a stand-alone ground rod independent from the service ground on your electrical service.
@Langmuir-Nick . Has there been a attempt to resolve this issue on future machine? Has it been resolved on the XR? Doesn’t seem to be a issue with them.
I would think that the main reason that this is a rare occurrence on the XR is the included mini-computer. We do occasionally still get this call on XR, the cause usually being the user didn’t utilize the included ferrite chokes or has switched to a laptop and is running off the charger.
Excellent point!
Would there be a consideration of having an add-on option for the PRO to have a mini-computer?
You can do it, just plug mini to usb cable and add a monitor cabled to mini computer.
I guess I am just looking for avoiding situations where the CPU is found later to not play well with FireControl like was found with some laptops:
When you are comparing and buying all the different things to get setup, it is hard to keep all the details straight.
Any intel processor without a U or an H should be superb. Unfortunately, most inexpensive laptops will come with the power saver chips. Use caution.
So you are saying the mini-computers do not have that issue?: power saving chip?
Most don’t. I use the Beelink computers for all my machines without any problems. I went on to buy 10 of them for our service and parts departments. Even our security camera system uses one. I’m sold on them. They are not for fusion or design work but to initiate NC files or stuff like that. They are great. Fusion works on them, but the dreaded video capacity prompt comes up on the Fusion screen. It does work, though. Not one failure at all over a couple of years now.
As far as I know, we do not currently have plans to add a mini-computer addon for the XF or XF Pro.
@Bigdaddy2166 may be onto something if you’re just looking to run your file from this computer and have something separate to design on, no point in breaking the bank.
If you’re looking for specific model recommendations for a machine to do both on, DM me. I could discuss PCs all day if time permitted, but don’t want to get this thread off-topic.
Appreciate the reply.
Six months ago my Dell laptop, bought specifically for the Langmuir table, went belly-up for a second time. (It still sits DOA on my desk…trying to decide to smash with hammer or consider fixing for a second time in less than a year).
I thought long and hard on the mini-computer but decided to get a “Professional” grade operating system HP laptop. This gives the flexibility of using/designing with Fusion 360. I am really liking this choice and am using it with my 3D printer as well. If it goes belly-up then I WILL go this mini-computer route.
I am hoping I don’t have to make that decision for awhile. Fingers crossed 
I am just collecting information for the next time.
Yes he is and I think it is MY billfold!
Hi,
Yes, it s called a ground loop. The proper solution is to ground everything together. And you need to choose one place to connect all of the ground wires. The table and the plasma power supply need to be grounded to the same place the computer is plugged in. By using one point to ground creates a STAR ground and minimizes the possibility of a loop. Note: a ground loop is like a transformer, energy passing through the loop is forced into the wires that make up the loop or loops. This induced voltage can easily overpower the desired signal in the wires.
Any and all cables should be shielded cables. The cable shielding normally should be grounded at one end only (nearest the master ground point). Both end shield grounding is better than no shielding. Cables should not be routed next to each other, as the high energy in one cable can be transformed into the other cable next to it.
The computer power supply module is normally electrically isolated, but not always. The RF energy from the plasma torch could be radiating into the wiring between the computer and the controller and is messing up the control signals.
I do NOT recommend that you cut off the grounding wire to the computer, that is a recipe for disaster.
Shop electrical noise can make a mess of any project, and proper grounding and careful grounding and routing of your cables is essential.
A common viewpoint, but I suggest an alternative view.
Starting with the knowledge that the Work Clamp is used to Sense the Current produced by the Torch AND is, by its nature, ALWAYS connected (through the slats) to the Table (at least upper portion), and is also the return for the voltage measuring the height for the THC circuit, then it makes sense to isolate this from any other loads or electrical sources.
To accomplish this, then ISOLATING the control electronics from the table should be the goal. I achieved this by getting rid of the original enclosure supplied with my system, replacing it with a polycarbonate splash proof enclosure, and combining the NECESSARY electrical grounds, in a Star fashion as @PixelTamer suggests, inside that enclosure. By ‘necessary’, I mean the control board which includes the USB V- and its auxiliary power supply -. It does NOT include the motor power supply or stepper motor drivers as these are already isolated, no point in mixing them into the electrical ‘soup’. The power supply’s ground is returned by way of the Ground wire in the power supply cable. It does not need to be connected to anything else within the enclosure.
For THC control, I installed mine before LS introduced their THC system and I’m glad I did as I’ve avoided all the problems that come up with the LS system. I use the THC-3T which uses an Isolated Differential Amplifier to monitor the Torch voltage and works very well.
I made these changes slightly over 4 year ago and I have NEVER had an electrical noise problem on my system and THC is rock solid.
In my opinion, grounding everything together is a serious mistake. However, with the existing LS THC system, it may be a necessary one. A better solution is replacing the Torch Voltage sensing circuit with an isolated differential amplifier (there are some very good ones on the market now) and separating the circuits.
Hi,
By adding an isolated differential amplifier, you essentially break the loop noise in two ways. The isolation breaks a loop and induced noise current can’t flow. A differential circuit cancels out the induced noise in a loop because the noise is added to both the send and return wires with a difference of zero noise out of the amplifier, so both methods are very good choices.
A good grounding practice is usually the way to start, but there are exceptions when having high current energy and sensitive digital circuits near each other.