hello I have a problem with the usb connection for the blackbox, I built a cnc plasma, everything worked perfectly until I connected the cutting machine (plasma), then it started giving errors and then it stopped connecting via usb, I want to mention that everything is very well sheldeed. Can you help me with an idea about how I could restore the usb connection again?
Can you provide some pictures of the wiring, what type of plasma inverter it is, etc for review, lets see if we can spot something that might help. Also provide pictures and writeup of how you did the shielding - what did you connect the Shields to? Both ends, or only one end etc?
All cables are shielded.the sheild is connected to machine one end and the other end to the metallic component box, I got EMI problem and then no USB connection
Hard to review how the Inverter was wired to the BlackBox from the pictures, but mainly I'd say something went wrong when you added the Plasma. What exactly, we'd have a hard time confirming from the pics. Sadly that indicates the moment it happened to cause damage, so the mission would be to find how/why Some generic tips: Could be caused by the extra shielding If not done correctly, star formation, only one end, to a proper seperate earth spike or bonded earth connection to avoid floating earth voltages - the shields themselves can raise in voltage in the presence of nearby induced fields. If somehow connected to DC GND instead of isolated earth - can cause damage Shields are last resort for EMI issues, causes more trouble than they fix. With EMI you want to address the SOURCE of the EMI rather than trying to protect every victim with a mitigation strategy like a shield etc. Find and fix where the EMI comes from instead. No device SHOULD be emitting EMI so bad that the other devices can't work - if it does, that device that does the emitting is the problem Otherwise Could be cross talk of high voltages to the low voltage cabling - noting Mains socket on the gantry etc that shows some habits of mixing high and low voltage cabling locations - running a mains cable in parallel to a low voltage signal cable, acts like a transformer, and with both cables about the same length where they run next to each other, almost a 1:1 ratio sometimes. Can induce damaging voltages. Could be a short etc - while adding the plasma, there was some work on adding wiring. Even if the wiring being added was not directly incorrect, perhaps wiggling nearby loose wires etc could cause a short - so recheck all wiring Incorrect pins on Plasma: If the Plasma has both trigger inputs and THC outputs on the same port (some do) - some Plasmas provide direct torch voltage, or divided torch voltage on the CNC port for THC systems to read the voltage to determine the cut height - make sure that was not wired incorrectly Incorrect pins on BlackBox - Sure you wired to Relay and not to perhaps PWM or Tool Enable which are 3.3v logic signals. Most plasmas use the relay's dry contact. Could also be stray voltages from the plasma torch/clamp making its way into the low voltage sections etc.
