CompactRIO not powering up?

[Matt382]

Our current situation is that our cRIO shuts itself off. When we first power the robot up, the lights blink and flash like they are supposed to, but a few seconds later, the lights and the cRIO itself turn off. When we check the voltage with a voltmeter, the Power Distribution Block is giving out 24 volts when not plugged into the cRIO. But when it is plugged in, the power supply is 14-15 volts.

Basically we think the problem has something to do with either a short within in the cRIO itself or the PD board. Any thoughts?:confused:

[keehun]

Did you try some replacement parts?

[Russ Beavis]

You should confirm that your cRIO's metal chassis is isolated from the robot's frame. You may have something else touching the robot frame which is then forcing the 24V supply's ground return breaker from tripping. A simple test would be to remove the cRIO from your robot and see if it has the same problem when off the 'bot.

Russ

[EricVanWyk]

Try a different battery.

Also, measure the battery input voltage unloaded and loaded.

[crake]

Our current situation is that our cRIO shuts itself off. When we first power the robot up, the lights blink and flash like they are supposed to, but a few seconds later, the lights and the cRIO itself turn off.

This is very strange - can you put it into safe mode and get it to boot?

[Steigerwald]

I believe you have a bad regulator inside the power distribution panel. I have seen the problem before with regulators which give lower voltage as the current demand goes up. I would check your power panel first. Possibly open it up and see if anything is blown. But before you do that, make sure to check your battery.

[Matt382]

Thanks for the responses. We tried a few different batteries and only one of them actually worked, which seemed weird. Then we opened up the cRIO and found lots of metal shavings, which obviously should not be there. So we blew those out and put it back together and it works fine now. Now my only question is why did one of the batteries worked while the others didn't? edit: All the batteries were charged, except the one that worked was at about 10.8 volts

[Russ Beavis]

A lead-acid battery at 10.8V without any load attached would indicate a relatively discharged battery. Even when mildly-loaded, the 12V MK battery should stay above 11V for quite a while.

As Eric VanWyk alluded to in a previous email, a discharged battery can result in the symptoms that you've described. The 24V boost converter only works down to about a 4V battery voltage. If you've got a discharged battery, the converter might work fine when the cRIO isn't attached but, upon attaching the cRIO, the supply might struggle to boost if the battery droops further to account for the extra load.

I hope that you opened the PD instead of the cRIO. Why are there metal shavings in your electronics? (insert yet another reminder to teams to please stop doing this...)

Russ

[crake]

I hope that you opened the PD instead of the cRIO. Why are there metal shavings in your electronics? (insert yet another reminder to teams to please stop doing this...)

We are seeing an increase in cRIO's needing repairs due to metal shavings. It is important for teams to keep their electronics clean - as a hard bump could dislodge debris and short out something important!

[Al Skierkiewicz]

Matt,
Debris is not uncommon, I advised many teams to get a vacuum and attack the Crio and other electronic parts while in Atlanta. You are lucky that the severity of the short did not render your Crio permanently damaged. Erik has stated that the PD 24 volt power is protected by a 3 amp resetting circuit breaker in the PD. The fact that your 10 volt battery did not react the same way as other batteries just indicates you did not leave the Crio powered long enough for the breaker to trip. At 10.8 volts, the battery likely could not develop enough current to trip the breaker in the same time period as a fully charged battery.

[pyr0b0y]

Our team had the same problem with the metal shavings, it would shut down our cRIO everytime. No one ever thought that it would have anything to do with the metal shavings. As soon as we took care of the shavings, we did not have anymore problems....the smallest things sometimes cause the biggest problems

[crake]

Our team had the same problem with the metal shavings, it would shut down our cRIO everytime. No one ever thought that it would have anything to do with the metal shavings. As soon as we took care of the shavings, we did not have anymore problems....the smallest things sometimes cause the biggest problems

Here's a little bit of insight into how metal shavings can affect the cRIO. Metal debris inside of the chassis can, at any time, cause shorts internally. You may be really lucky and short out two nets with no problem. Or, slightly less likely and short out signals that will cause errors (e.g. a data line is shorted to GND). Or, very unlucky, and the short can cause permanent damage.

In the event something unexpected occurs, and a bad instruction is executed, or a data is corrupted, the cRIO will most likely reboot (processor exception). If a power rail shorts out, depending on the location the cRIO will shut down (over-current protection), or the internal safety fuse will blow.

One nasty problem with debris is that you may not have a problem until you hit something, which could be in the middle of a match! Bad news there...

So keeping the cRIO (or any of the electronics for that matter) clean is critical, and so we're looking into documenting a procedure teams can use to maintain their hardware.

[Al Skierkiewicz]

Chris,
Has NI received any Crio back with metal shavings in it that caused damage? Can you post pictures or start a thread so we can hammer this point home? Metal shavings, metal flakes and metal dust from any source can be a hazard to all of the electronic components. I had a team many years ago who mounted their speed controllers next to an open frame transmission. As the gears wore themselves in, the metal flaking off, landed right in the speed controllers. One after another died from this "metal fatigue".

[crake]

Chris,
Has NI received any Crio back with metal shavings in it that caused damage? Can you post pictures or start a thread so we can hammer this point home? Metal shavings, metal flakes and metal dust from any source can be a hazard to all of the electronic components. I had a team many years ago who mounted their speed controllers next to an open frame transmission. As the gears wore themselves in, the metal flaking off, landed right in the speed controllers. One after another died from this "metal fatigue".

Yes, we have seen damaged controllers with metal debris inside, including one at CMP. I have some photos, but we could use some better ones for education (I'll ask RMA to get some good shots). I should also add that this year NI's RMA process was very lenient, but we should expect that in the future returns due to contamination may require charges for cleaning and repair.

Attached is one photo from CMP showing debris - inside the chassis had the same coating of plastic and metal bits.

[Al Skierkiewicz]

Thanks Chris,
To the others viewing this picture, this is not the worst I have seen.

[crake]

Thanks Chris,
To the others viewing this picture, this is not the worst I have seen.

We once found a WIRE inside, touching the fuse to the shell of the serial connector. And speaking of things not to do. Please don't do this (see attachment).