Electrically Nuetral

This is probably a really stupid question but, We are mounting our Jags and PD Board (electronics held on by plastic screws and or zip ties) on 1/8plastic which is then riveted onto aluminum plates. This would pass the rule that electronics must be mounted on an electrically neutral board

I’m 99.9% sure that set up will be fine. Just make sure none of your electrical components are touching the rivets.

Mounting those components onto plastic would satisfy R43 as long as there is no direct connection between the components and the aluminum.

Please note that there is no requirement to mount electrical components other than the cRIO and Axis camera in an electrically isolated manner. Those two components are the only two that are case grounded.

The plastic case of the PDB and Jaguars are not conductors and having these cases touch a metal part of the frame is not illegal or a problem.

Make sure that the ends of all wires are insulated and that the cRIO and Axis camera are mounted in an isolated way and you should be all set.

The real test you want to do is with a multimeter. You should see infinite resistance between the ground terminal on the power distribution board and the robot chassis. For that matter, you should see infinite resistance between any part of your electrical system and the robot chassis.

The test used by inspectors is this…

  1. disconnect battery
  2. Turn Main Breaker to “ON”.
  3. Set your VOM or digital multimeter to read ohms.
  4. Connect one probe to the robot frame.
  5. Connect other probe to the positive terminal of the Power Distribution Board.
  6. Note that reading is greater than 100K ohms.
  7. Move probe from positive terminal to negative terminal of the PD.
  8. Repeat step 6.
  9. Repeat steps 4-8 for other sections of the robot frame.
  10. Remove probes and turn Main Breaker “OFF”.
    If any measurements are well below 100K ohms, suspect a pinched wire, a wire strand between two terminals on any electrical component or the PD. If any measurements are below 100K ohms, check for insulation on Crio chassis and camera(s) chassis. As pointed out above, the Crio chassis and camera metallic case are electrically bonded to the common (negative lead) of the power supply. A very low reading on the negative terminal of the PD is likely one of these two components. COTS sensors of the KOP senor boards may also produce the same results if not properly insulated. A low reading on the positive terminal can be isolated by selectively pulling out the breakers until the reading returns to normal. The circuit protected by that breaker will contain the problem.

Al is wise. Follow the procedure described by him, and thou shalt pass inspection.