Common Langmuir Systems THC Issues and How to Fix Them

CrossFire ® PRO
1

Common Langmuir Systems THC Issues and How to Fix Them

Note: This guide assumes that your Plasma Cutter is wired to the VIM properly-- If you are unsure, please troubleshoot this first before proceeding.

With all of the batch 1 CrossFire PRO machines now delivered to customers, we’re able to take advantage of customer feedback to improve the performance and reliability of the machine, software, and electronics moving forward.

While most customers have not faced any issues with the THC, we have noticed that a portion of users are seeing some strange issues. The purpose of this document is to describe the different issues that some have faced and explain how to resolve them. Fortunately, many of the fixes are simple to make and we here to support with any questions you have. Please note that this document does not encompass all possible THC issues, but rather issues that are encountered despite wiring the plasma cutter and THC correctly per published instructions and following all guidelines related to creating g-code and running the machine. If you have questions about wiring up your specific plasma cutter for usage with the THC VIM module, we recommend reaching out to others on our User Forum.

This is also a good time to make sure that you are running the latest version of our THC firmware as it’s possible that your firmware is outdated and has known bug issues. You can find the latest firmware version and instructions for how to flash this firmware onto your THC here.

Issue #1: FireControl only partially cuts certain features before immediately jumping to the next cut even though the G-Code program is correct.

This happens when the USB ground has continuity to the AC power supply ground. The CrossFire PRO electronics are designed to keep the USB ground isolated from the AC power supply ground, but in some cases this is not the case. Below is a list of ways that there COULD be continuity between AC ground and USB ground:

  1. The Motion Control Board mounting nuts may have abraded away the solder mask and are now making contact with the USB ground plane of the board. Since the AC ground has continuity to the Electronics Enclosure case via the Power Supply mounting screws (for shock safety), the USB ground will then have continuity with AC ground. To check for continuity, put one Multi-meter probe on one of the power supply mounting screws and put the other Multi-meter probe on the exposed metal of the female USB port (make sure not to accidentally touch the sheet metal enclosure). Below is a picture showing this check. If you have continuity here the fix is to use plastic washers to electrically isolate the board from the enclosure. If you need these washers, please email us at support@langmuirsystem.com. Please note, continuity here is described as any resistance below 10kOHM.

anpbexrZBNYK9SdUGAO9huXLJJRp0lFEIkjh67S1ArAkxv055hdhs8jRevndzfU-qKNdatoCA-Dk1F5XCQBX0IvTX5upPnkRmSNv5TNWS0aW3SIFupCVnis3NWQFkKVPOw-BtaUy1200×1600

  1. The female USB port may be contacting the cutout in the Electronics Enclosure causing continuity between USB ground and AC ground. To fix this issue, use electrical tape to insulate the USB port.

  2. [For desktop users only] The USB ground may have continuity to the AC ground inside your desktop computer. To check for this, measure continuity the same way as in item 1 above, except be sure to have the USB cable connected and your desktop plugged into a wall outlet. If you do have continuity, you will need to supply power to your desktop using an Uninterruptible Power Supply. Fortunately these can be purchased somewhere like Amazon for less than $65.

Issue #2: Torch live volts are significantly lower than normal; in the 0-40 volt range. This may cause the THC not to make proper adjustment moves, and may cause the arc voltage lost alarm despite the arc not being lost.

This happens when the USB ground has continuity to the machine frame/work clamp from the plasma cutter. Below is a list of ways that continuity may be present and how to fix it. Remember, continuity here is described as any resistance below 10kOHM.

  1. The motion control board may have continuity to AC ground (see items 1-3, issue #1) AND the Electronics Enclosure case has continuity to the machine frame. To check for this, place one of the Multi-meter probes on one of the 4 power supply mounting screws, and the other probe on one of the slats. If continuity exists, physically remove the electronics enclosure from the leg and check for continuity again. If you no longer have continuity, it means the mounting hole isolating grommets have been compromised allowing the sheet metal mounting screws to make contact with the edges of the mounting holes. If this is the case for you, please email us so we can send you new isolation grommets.

  2. The laptop case may have continuity to the machine frame via a metal laptop stand. To check for this, place one Multi-meter probe on the exposed metal of the female USB port and the other on a slat. If you are measuring continuity, then consider using an insulating material between your laptop and the laptop stand tray.

1 Like