elim field issue?

[johnr]

I haven't talked to anyone on my favorite team 910 so i don't know if they found a problem when they stopped moving in quarter 4-3 but this is what i saw. They couldn't link up at start then got ok. Moved in auto then stopped. Lost match. RATS, lets see what is happening on curie. Team 888 having trouble linking up, quar 4-3. Gets ok. Doesn't move. Funy thing is same match,same side-red- same driver station, different field. Just wondering if there where any bots not moving around the tenth match during elims on the other fields? 910 was on newton.

[EricH]

Originally Posted by johnr

Moved in auto then stopped. Lost match. RATS, lets see what is happening on curie. Team 888 having trouble linking up, quar 4-3. Gets ok. Doesn't move. Funy thing is same match,same side-red- same driver station, different field. Just wondering if there where any bots not moving around the tenth match during elims on the other fields? 910 was on newton.

As a matter of fact, yes. 254, Archimedes SF1-1. Stopped right after auto amid defense from 330 and 3357 beating on 330 while 254 was on the other side. Stayed put all match, partially blocking one goal. 330, 25, 1622 won the match.

254 called a timeout and fixed their robot before the next match, so I'm not sure if it was a field issue or a robot issue. Red 1 station.

Team 888 didn't play in Curie QF4-3; Red 3, their station, was taken by 1421. (QF4-2, 888 was in Red 2. They were in Red 1 in QF4-1.) Please verify the match number.

910 was in Red 1 during Newton QF4-3.

[JeffChan]

2854 had the same issues starting qualification matches Saturday morning. Robot communication would drop half way through all three matches we played.

We were swapped out after Archimedes QF match 1 due to this issue.

[R.C.]

We had this issue but not at Atlanta. In 2 matches at Davis, we started our auto and then we didn't move in teleop. It seemed as the field missed our tele op. We called a timeout but couldn't see anything wrong. Next match we moved just fine.

-RC

[steelerborn]

I am not to savvy when it comes to electrical problems.
But we had a similar problem last year with current running through the bot.
What may be the problem is an exposed wire that was touching a metal part sending current through the frame. We had a hard time connecting to the field for all of our second regional last year.

If you guys were running then losing coms this may be the culprit.
Then when the bot goes back to the pit, to try and solve the problem the exposed wire may have been moved slightly, and not touching a metal component. This could have been completely by accident and the problem may never occur again. But you may be out multiple matches before the wire is moved.

I know that experience last year motivated us to mount all of our electronics on thick plastic to eliminate this problem (overkill because it added a ton of weight that wasn't necessary).

[MagiChau]

Originally Posted by steelerborn

I am not to savvy when it comes to electrical problems.
But we had a similar problem last year with current running through the bot.
What may be the problem is an exposed wire that was touching a metal part sending current through the frame. We had a hard time connecting to the field for all of our second regional last year.

If you guys were running then losing coms this may be the culprit.
Then when the bot goes back to the pit, to try and solve the problem the exposed wire may have been moved slightly, and not touching a metal component. This could have been completely by accident and the problem may never occur again. But you may be out multiple matches before the wire is moved.

I know that experience last year motivated us to mount all of our electronics on thick plastic to eliminate this problem (overkill because it added a ton of weight that wasn't necessary).

Use zip ties :O

[Ryan Gordon]

Originally Posted by steelerborn

I am not to savvy when it comes to electrical problems.
But we had a similar problem last year with current running through the bot.
What may be the problem is an exposed wire that was touching a metal part sending current through the frame. We had a hard time connecting to the field for all of our second regional last year.

If you guys were running then losing coms this may be the culprit.
Then when the bot goes back to the pit, to try and solve the problem the exposed wire may have been moved slightly, and not touching a metal component. This could have been completely by accident and the problem may never occur again. But you may be out multiple matches before the wire is moved.

I know that experience last year motivated us to mount all of our electronics on thick plastic to eliminate this problem (overkill because it added a ton of weight that wasn't necessary).

For us, we had several of the experts check it, including Big Al, all with the prognosis that everything is fine.

We're still not sure what was going on. We replaced a Jaguar that we thought might've been shorting but it still happened. Our last guess was the wireless bridge but there were no more wireless bridges to test it out.

We were literally standing next to 254 on the Archimedes field when their robot lost comm. during the elim. rounds and it exhibited exactly the same symptoms we had.

[Alan Anderson]

A working autonomous but no control during teleop is a pretty specific symptom. It points to the Classmate losing its connection with the USB devices. Letting it go to sleep before connecting to the field has been known to cause this problem. It can supposedly be recovered from by rescanning the input devices.

[sgreco]

Originally Posted by R.C.

We had this issue but not at Atlanta. In 2 matches at Davis, we started our auto and then we didn't move in teleop. It seemed as the field missed our tele op. We called a timeout but couldn't see anything wrong. Next match we moved just fine.

-RC

My team had the exact same scenario in Boston in a qual match, Moved in autonomous, then no movement in teleop, couldn't find a problem, didn't change anything, then worked perfectly fine in the next match.

[Bill_B]

Originally Posted by steelerborn

I am not to savvy when it comes to electrical problems.
But we had a similar problem last year with current running through the bot.
What may be the problem is an exposed wire that was touching a metal part sending current through the frame. We had a hard time connecting to the field for all of our second regional last year.

.....

A single exposed wire touching the frame would not cause current to run in the frame other than charging its capacitance, that is, minuscule. The possibility of serious short circuits is the principal reason FRC robots are forbidden from using the chassis grounding method that is nearly universal among automobiles. In that case, a wire that contacted frame metal via frayed insulation would almost certainly be a short circuit.

Part of your electrical self-inspection should be a voltage check between all of your fuse-block outputs and the frame. It should be zero in all cases, of course. Resistance checks are a bit trickier, but so is infinity. Just ask Buzz Lightyear. I haven't watched event inspectors, but I'd guess they do some elementary measurements, don't they?

[johnr]

Erich, where you watching the match when 888 went dead? If you are going by the posted results i think there is something wrong with them or i may be totally mistaken on the location of driver station. I do know that they worked on that bot a long time and maybe i just saw people working on it and figured that was the team behind glass. After about sixty matches, to go down without a fight is just a bitter pill to swallow. I just feel really bad for our seniors.

[Tom Line]

Originally Posted by Alan Anderson

A working autonomous but no control during teleop is a pretty specific symptom. It points to the Classmate losing its connection with the USB devices. Letting it go to sleep before connecting to the field has been known to cause this problem. It can supposedly be recovered from by rescanning the input devices.

We had this issue once, at the West Michigan District. The quick-thinking driver and driver coach rescanned the devices and then was able to start driving.

[Liz Smith]

Originally Posted by johnr

Erich, where you watching the match when 888 went dead? If you are going by the posted results i think there is something wrong with them or i may be totally mistaken on the location of driver station. I do know that they worked on that bot a long time and maybe i just saw people working on it and figured that was the team behind glass. After about sixty matches, to go down without a fight is just a bitter pill to swallow. I just feel really bad for our seniors.

Apparently, 888 narrowed down their issue to a bad digital sidecar. One indication was that their RSL never turned on at all. Tough break that it happened in the crucial elimination rounds.

[EricH]

Originally Posted by johnr

Erich, where you watching the match when 888 went dead? If you are going by the posted results i think there is something wrong with them or i may be totally mistaken on the location of driver station.

I was going by the posted results, as I was really only watching Archimedes. I'm guessing that you got the wrong drivers station, or the wrong match, or maybe they hadn't changed the number yet.

But, if it's a bad digital sidecar, then it is not a field issue, at least on that field.

So far, we've had:
888, Curie--bad sidecar.
910, Newton, QF4-3--unknown (Red 1). Suspected that the Classmate lost USB.
254, Archimedes, SF1-1--unknown (Red 1). Suspected that the Classmate lost USB.
2854, Archimedes, quals/QFs--unknown, different symptoms.

Sounds like a coincidence to me.

[steelerborn]

Okay thanks I love learning about new things.
That is what first is all about.

Actually we also didn't isolate the crio from the frame.

The ispectors did a great job and did check.
But we went through with a bad crio.
When we told them we would have to switch it out they just said okay and let us go through.
When we were mounting it we had someone make a mistake.
So that was our problem.
I just had to ask a mentor to get the exact reason.

But I think it sounds like just a coincidence too. With different symptoms as well.