Hello all, Well this one seems like a strange problem and has me a little baffled why my CNC BlackBox keeps losing serial COM3 connection with the computer Openbuild Control software. The only possibility I can think of is that the 3PH 2.2KW spindle with VFD is not grounded enough and some how back feeding current or that a magnetic field created by the spindle is some how interfering with the COM signal. I'm really not sure here and would appreciate some ideas and suggestions on what to look for or strategies on how to troubleshoot? What would cause a lost usb serial COM3 connection? The green Connection button seems to grey out when it happens like it suddenly lost signal or disconnected.
Here is a copy of the G code when the problem occurred. [21:24:59] [ $$ ] ok [21:24:59] [ $I ] [VER:1.1g.20181112:] [21:24:59] [ $I ] [OPT:V,15,128] [21:24:59] [ $I ] ok [21:24:59] [ $G ] [GC:G0 G54 G17 G21 G90 G94 M5 M9 T0 F0 S0] [21:24:59] [ $G ] ok [21:25:00] [ $J=G91 G21 Z1000 F630 ] ok [21:25:00] [ connect ] Firmware Detected: grbl version 1.1g on COM3 [21:25:21] [ ] PORT ERROR: Writing to COM port (GetOverlappedResult): Unknown error code 31 [21:25:21] [ disconnect ] PORT INFO: Port closed [21:25:21] [ usb ports ] Detected a change in available ports: [ No devices connected ] [21:25:45] [ usb ports ] Detected a change in available ports: [COM3]
In addition to the link @Peter Van Der Walt gave, your cable from the vfd to the spindle is very close to the cables to the blackbox. Physical distance between a source of emi (vfd's chuck out loads) and a receiver (usb cables are particularly susceptible because signal levels are low) is the best precaution you can take. Alex.
Peter thank you for the EMI link. I will try the listed solutions. Alex thanks for the suggestion as well. It would probably help to separate the controller from the spindle wiring.
