I've seen a lot of threads about EM interference in the wires, but If one exists, I haven't seen anything about it in the endstops themselves. I have the Workbee 1010 kit with the blackbox and a 3ph spindle driven by a VFD. My issue is the spindle is causing the Z endstop to trigger. I plugged each endstop in by itself with separate twisted pair wires, and only the Z endstop triggers from the spindle. Has anyone had to put shielding around the endstop to fix this? I'm thinking about 3d printing a little box for it with aluminum tape around it. I also had to replace the stock USB cable with a much better shielded one because the spindle was causing Openbuilds Control to freeze. This thing is seriously noisy.
It is still most likely that the wiring is picking up the emi - the lead from the vfd to your spindle is the main source and physical distance the best solution - obviously difficult if your Z switch is close to the spindle. Another source though can be the spindle casing - it should be connected to mains earth, but many Chinese spindles do not have a connection between pin 4 on the connector and the case, so you may have an earth lead that only goes as far as the connector on the top of the spindle. You can then get quite high AC voltages induced on the metal case of the spindle. Check (with everything disconnected from the mains - I have to say this after watching a video of someone using a meter on resistance setting to probe the connector with the spindle running) for continuity between pin 4 on your spindle connector and the metal case. Alex.
See docs:blackbox:faq-emi [OpenBuilds Documentation] > Section 2.4 In particular, see section 2.8 docs:blackbox:faq-emi [OpenBuilds Documentation] - follow the link at the end of the paragraph as well for further reading
Thanks for the replies, the information was helpful. I ended up having to switch the motor's wiring to braided shielded cable with the shield grounded. Now it's running quite well and I haven't had any more EMI issues since.
