Issue type: Equipment Problem Area: Metal Shop Equipment: Tormach PCNC 1100 Summary: Probe cable causing probe crashes Additional Info: Recently some users have had unexplained probe crashes, where the probe flashes red but doesn’t communicate to the tormach that it is activated. I switched to a backup probe and the issue didn’t happen until about 200+ probes, at which point it also failed to report a probe hit. When I wobbled the connector in this state, it once again reported probes properly. As a result, I soldered a new USB-C connector to the plug. The current probes we have all seem to have sustained crashes and they are quite difficult to align concentrically. Probe is currently not calibrated, but it is electrically operational. I suggest using the edge finder/wobbler until this is resolved.
I’ll bring in a known good probe in the next 1-2 days to compare and verify it’s functionality, then epoxy the usb connector to the probe once it’s all set up.
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For what it’s worth, epoxy won’t hold it together, I tried that when I first built that setup, before I tried hot glue, which also doesn’t hold it. Given it’s become an integral part of the machine setup, I’m wondering if we should look at a different option.
I had similar thoughts about other options. Both Al and I have been using a Chinese wireless probe, the GP-800 which can use Renishaw breakaway tips. It’s about 350 USD and has so far worked excellently.
Batteries are definitely a concern, I don’t know if the tormach is capable of using the extra input/output pins to do two way probe communications.
Another option would be direct wiring these cheaper probes and cutting the usb connector off entirely. It would prevent connection issues causing crashes, but also would require modifying any future probes too.
Probe is back in service, calibrated to under a thou of concentric and adjusted for the new probe length and diameter. There is one probe tip in reserve other than the one currently on the probe.
To try and address the cable losing connection issues, I initially disassembled a damaged probe, de-soldered the USB-C port, and soldered a cable direct to the probe PCB. I noticed afterwards that the USB-C port is used to keep the circuit board aligned inside the probe, which meant it wobbled and rotated internally.
Left to right, the 6 pads at the bottom of the probe PCB are Ground, VIN, Signal, Signal, VIN, Ground.
I ended up changing plans, and modeled a piece of plastic that holds the USB-C cable to the probe, and also tightly holds the probe body, both using a M3 screw and nut for tension. This prevents the machine’s motion from wobbling the plug around which is what I suspect was causing the crashes.
