I have had my project sitting in a corner for a few weeks now due to an issue with losing the connection with the Advanced Servo controllers.
This is the current setup and a description of the environment that is operates in:
-Win XP PC with VB6 program
-USB extender rated at 100 ft. limit with 50ft cat6 cable
-3 Advanced Servo Controllers
-6 individual 3 DOF arms built on paralleled Hitec HS-645MG servos for shoulder and elbow joints and single HS-645MG's for the wrists.
-servo leads are about 4 ft. long and are made from a sheilded cable, grounded at the cabinet end only (where the servo controllers are)
-arms are mounted about 6" apart
The PC is in a cabinet 10 feet away from a steel paint booth where the arms are installed on a DC motor-driven carrier running along an "I" beam 20 feet long. The arms purpose is to position small paint heads that spray material 16 feet long of many different contours.
The issue that I am having is that whenever I run the fan on the paint booth the controllers will occasionally disconnect with from the PC. When they disconnect they no longer not show up in the Phidgets Control Panel or respond to the software.
I have tried putting a power filter at the 110v source in the cabinet above the paint arm that house the Phidgets, hoping to eliminate any EMI from that end but this causes the arms to jump around as soon as I turn the booths fan on. I have even tried using an SBC wirelessly at the paint head end to eliminate any possibility of EMI through the network cable.
The question (at last) is, how can I reduce / eliminate the EMI from the booth fan and other sources that are causing the unit to disconnect from the PC? I have read about the EMI issues that stem from long servo cables on RC models, but have not found anything that will resolve this issue.
Any thoughts on what I could try? The thing runs flawlessly on the test bench, complete with the 50 feet of USB extension. Everything is the same on the test bench as when it is installed except the fact that it is installed on the steel beam, is in the paint booth and is next to the drive motor for the carriage that it is mounted on.
I am really stumped, any suggestions would be appreciated.