Need help diagnosing a problem

[Canon reeves]

Our team competed at the Arkansas Regional and we ran practice matches all Thursday, no problems at all. There was no score keeping during these matches and we did good. During our first qualification match we ran great until the last 15 seconds we lost power to the C-Rio, and all Comm. and Code. During the next match our battery fell out. And in every other qualification match we would run, then our C-Rio would reboot. Sometimes it would happen when we took hard hits, others we would just drive forward and then reboot. So first we replaced the C-Rio, same problem, all of the wiring was fine, had multiple inspectors confirm that, Then we replaced the PD board, took it to the practice field and it worked fine, we ran at full speed into the low goal multiple times, it was just fine. Then we went onto the field on saturday and same problem happened. We replaced the main breaker, same problem. So then we got picked for elims. and during the time in-between our match, we ran on the practice field with our alliance members at least 20 minutes, just fine. We went out on the field, drove a little bit, and re booted. same thing happened next match. Any ideas what could be the problem? I had started another thread under the wrong forum, here is the link to it. http://www.chiefdelphi.com/forums/sh...hreadid=127617
It would seem as if it is a wiring issue or a short caused by hard contact, but in this match we didn't see much, and in another we simply drove forward in autonomous and rebooted. https://www.facebook.com/photo.php?v...type=2&theater

[Joey1939]

We were also at the Arkansas Regional and had similar problems. Our cRIO would reboot randomly during matches. The CSA looked at our logs and identified that the cRIO rebooted because of several severe voltage drops. The problem was identified as loose battery connections. If the connection leads to your battery wiggle at all, they need to be secured. We re-did several of our batteries and didn't have anymore problems.

[Canon reeves]

They checked ours too, and they didn't find a problem with it, except for the last match was an iffy battery, and even then they couldn't get it to shut off when they wiggled the anderson connectors? We could just move forward and reboot? We really enjoyed playing with yall, and congrats to Izzy and the teams chairmans!

[cglrcng]

I posted over at your other thread...Check the Radio Power Converter for a crossed over center ground wires possibility. (black nearest the yellow should be paired w/ the yellow / black nearest the red should be paired w/ the red). We had same issue w/ our practice bot recently...Fixed it only, no more intermittent loss of connection issues now.

[Tyler2517]

We are using a CAN bus and we found that when the voltage drooped the can controller would brown out and die not restarting for the rest of the match. After much tinkering we figured out it was due to the fact that we are running batteries that are up to 5 years old and cant hold a charge to save their lives.

[Greg McKaskle]

The log file viewer can be launched from the Start menu or the Charts tab, lower right button. Scroll the listbox to the appropriate date, typically the bottom line or near the bottom. The graph will show CPU, battery, comms latency, and comms loss on the majority of the graph. Gaps in the battery with an orange vertical marker on the left and a green vertical marker on the right are a disconnect from the field. It is often useful to change the filter ring above the graph from Default to one of the All settings. Then zoom to the orange/green band and you should see additional yellow markers for the ping results. You can hover your mouse over any marker symbol and the Message box in the lower left will give the text of that message.

There are three common occurrences -- loss of radio and cRIO, loss of only cRIO, and loss of only radio. If there is a yellow vertical marker in-between the orange and green, the hover will likely say that the Radio was lost. This message is the cRIO tattling on the radio. When the cRIO loses its communications protocol during a match, it tries to ping backwards up the chain while the DS pings down the chain. This can help pinpoint where the drop happened. When the cRIO comes back in communications, it gives a post-dated message explaining that it was powered and saw the robot radio go away.

If you do not see that marker, look at the first yellow dot near the orange vertical marker. Hover and it should give the ping status of each comms element. It will tell you whether the robot radio was good or bad.

What this information can help with is to identify which element rebooted during the match. This tells you which connectors, cables, and wire routes to focus on. Please keep in mind that if both elements rebooted, the problem could be a short or open at the battery terminals, the breaker, or the PD.

If you are losing the radio, please verify that it is connected to the 12/5 regulator powered from the 12V boosted circuit on the front of the PD next to the cRIO power port. If you power it from an unboosted 12V along the sides of the PD, they will droop and you will lose the radio during a match. Also do not power the radio from the 5V camera port on the front of the PD. I do not believe it is as protected as the 12V.

I know this is a long post, but one more topic. If the robot stops moving, but the Communications and Robot Code LEDs remain lit, the issue is likely at the digital breakout board. Inspect the three LEDs near the RSL connection. If the 5V LED is out, look for debris that is shorting pins or possibly replace. This 5V is for the PWM signals. If the LEDs are good, look at the ribbon cable connectors. Also verify that the digital module is firmly snapped into the cRIO.

Greg McKaskle

[MikeE]

Could you post the video somewhere where dinosaurs like me who don't use Facebook can see it?
Sometimes there are visual clues. e.g all the lights dimming on the robot just before a reboot which implies severe voltage drop (old battery/high current drain or sometimes a short).

[annie1939]

We experienced this problem (among many) at the Hub City Regional. It ends up we were stalling motors which drew a lot of current and dropped the voltage at the radio which caused it to reset. It didn't happen on the practice field because it was tethered, but the minute we were driving in a match, the communication dropped. We were frantically rebuilding our drive train so that we could compete. Unfortunately, we got the last bolt in AFTER our last match.

[Canon reeves]

Originally Posted by annie1939

We experienced this problem (among many) at the Hub City Regional. It ends up we were stalling motors which drew a lot of current and dropped the voltage at the radio which caused it to reset. It didn't happen on the practice field because it was tethered, but the minute we were driving in a match, the communication dropped. We were frantically rebuilding our drive train so that we could compete. Unfortunately, we got the last bolt in AFTER our last match.

What caused yall to stall motors? Really sorry this happened to yall! I know it is a rough feeling!

[Alan Anderson]

I posted a long answer in the other thread.

[annie1939]

Our problem was from our own making. I pointed out that the SLOW speed of our transmission was geared to go 19 feet per second, and that the max at high speed should only be around 15 feet per second. The build team chose not to make the change. I didn't realize that the problem would manifest in the way it did, but I packed the parts to make the change because I knew it was coming. It was a hard lesson to learn, but one they won't make again. I felt bad for our alliances that had to play with only 2 players, but we were pretty much a brick. We have one more regional where I hope we will do better.

On the other hand, it was interesting to note how much luck can affect your final ranking. We ended up 25 out of 42. I lost track of how many rounds we missed, but it had to be more than 4. It just emphasizes how important that scouting data is. We were close enough to the top 24 to be considered by an uninformed team. Although we were running by that time, I advised the team to decline any selection in the unlikely chance it occurred. We just were not reliable enough.

[Doc Wu]

We have seen defective main (150A) circuit breakers that would open under high vibration, sometimes even popping open/off.

Lightly tapping on the breaker would sometimes replicate the problem.

One more thing to add to the check list.

[Canon reeves]

Originally Posted by Doc Wu

We have seen defective main (150A) circuit breakers that would open under high vibration, sometimes even popping open/off.

Lightly tapping on the breaker would sometimes replicate the problem.

One more thing to add to the check list.

We did discover something similar to this I believe, we could force a shut off by wiggling one of the connectors, another great catch by our CSA Alan, I have no idea what we would've done without him or people like him, thanks for the advice. Tomorrow we plan on testing all of the connections with a multimeter after some driving, I will post an update on our findings then.

[jimwick]

We had a similar problem and it turned out to be a defective power connector to the radio. Check that. It's an easy fix.