PDB 24V keeps dying

[jsasaki]

The 24V ports on our PDB keep dying. The green LED stops lighting up after seconds of running our robot. So far we have 3 broken power distribution boards....:mad: An ideas why?

[Garten Haeska]

Do you drill over your robot causing them to short out often?

[jsasaki]

Do you drill over your robot causing them to short out often?

nope. This is our third PDB and I just changed it 10 min. ago. drove for about a minute and it stopped

[Garten Haeska]

Is your Crio electronically isolated from your frame?

[jsasaki]

Is your Crio electronically isolated from your frame?

the whole electronics board is on lexan.

[Garten Haeska]

Yes but lexan can still carry a current for approx. 4-6in. When mounted directly to the frame.

[jsasaki]

what would you suggest for me to do ?

[Garten Haeska]

When you touch the robot do you might get shocked but when you touch say a bolt on your lexan board do you get shocked? If so you need to isolate your board.

[jsasaki]

heres a picture

[jsasaki]

nope not getting shocked.

[EricVanWyk]

Garten, I'm very confused by several of your responses in this thread. Do you have data to support your claims that Lexan can conduct electricity 4-6 inches and that the voltages on the robot are sufficient to cause noticeable electric shock?

Jsasaki, verify frame isolation with a meter. Then, check the insulation on the wires coming off the right hand side 40A breakers - you may be shorting there.

[its da PAT!!!]

It would be nice to see the other end of the four pin connecter.

[its da PAT!!!]

Also, those wires touching the Crio from the jag in the upper right corner at touch the Crio and those are getting power.

[Cecil]

Looks to me like the wire on the 5 volt camera plug is a little long.. Either that, or it's something blocking my view..

[its da PAT!!!]

Looks to me like the wire on the 5 volt camera plug is a little long.. Either that, or it's something blocking my view..

Yea I saw that too.

[jsasaki]

more pictures

[richwong]

In the 24v connector on the PDB, there are four wires connected. Only two should be connected. I see that there are only two wires on the CRIO end. Where are the other two going? It looks like it might be the sidecar. The sidecar should be fed by 12v on a dedicated 20A breaker.

[richwong]

In the 24v connector on the PDB, there are four wires connected. Only two should be connected. I see that there are only two wires on the CRIO end. Where are the other two going? It looks like it might be the sidecar. The sidecar should be fed by 12v on a dedicated 20A breaker.

I just looked again and it looks like the second set of wires is going to your analog breakout. That should also be powered by a dedicated 12V 20A breaker.

[Mark McLeod]

The second set of 24v wires feeds the solenoid breakout (properly).

I'd suggest a systematic step-by-step isolation of the problem.
If it's repeatable in a timely manner.

Example given:
pull all the power breakers
pull the camera and radio power
pull the 24v connector
Turn the system on, see if the 24v power light goes out
if not:
Add in the power breakers
Turn the system on, see if the 24v power light goes out
if yes, further isolate the offending breaker
if not:
Add the camera and radio
Turn the system on, see if the 24v power light goes out
if yes, further isolate which power causes the problem
if not:
pull the two remaining cRIO modules
pull the solenoid power separately from the Breakout
Add the 24v power back for just the cRIO chassis
Turn the system on, see if the 24v power light goes out
if yes, probably remove the cRIO and do an internal cleaning, per NI directions. Retest.
if still yes, pull the second set of 24v wires from the connector and retest.
Check the module pins as well
if not:
Add the Digital module
Turn the system on, see if the 24v power light goes out
if yes, test in the alternate digital module slot, as well to see if the problem follows the module.
if not:
Add the unpowered solenoid module
Turn the system on, see if the 24v power light goes out
if yes, test in the alternate digital module slot, as well to see if the problem follows the module.
if not:
Add the 24v solenoid Breakout power
Turn the system on, see if the 24v power light goes out
if not: (the gremlins have won)