COMM lost way to many times

[bdaroz]

Originally Posted by Lil' Lavery

What in the video establishes that there was no power loss on the RoboRIO? If you're just looking at the Robot Signal Light, it's possible that your RoboRIO browned out due to power loss, but didn't completely shut off.

I was going on the basis that our battery voltages were very good (and trending up), and our load was low at the time (and trending down). It was the CSA & FTAs opinion that we lost power completely and the RoboRIO rebooted, however the video of the lights on the RoboRIO (and RSL) didn't concur with that assessment.

Is it possible it was a brown-out, sure, but my point is that there isn't enough data because of the streaming-only nature of the logging mechanisms.

[mwtidd]

Originally Posted by Tanis

I highly recommend against hot gluing the plug into the radio (and I also advocate against hot gluing or taping ethernet cables and power cables pretty much anywhere). It makes replacing those wires later more difficult.

The radio's plug is particularly problematic with hot glue. You can no longer easily detach the radio from your robot to program it at events, and swapping out radios should yours need to be replaced for any reason suddenly becomes much more difficult.

Furthermore, the issues I have seen are generally not that this plug comes loose. The problems are generally that the wires going into the Weidmuller connections on the VRM have too much copper showing and are shorting out, or that there are loose wires elsewhere in the chain.

I had a team that had mummified their Ethernet ports on both the radio and roborRIO along with the USB cables going into the roboRIO and the power plug on the radio with electrical tape drop out during a match. Seriously, there was a large mound of the stuff over everything. They asked me if I thought they should add more electrical tape since they were still dropping out. At that point I demonstrated that the wires going to their radio were just falling out of the VRM with very little effort on my part.

Understand the problem before trying to apply bandaids. You might not even be putting the bandaids in the right spot.

Great callout Bryan. As he said, you should not have to apply hot glue on the connection between the radio and the plug, and that can definitely be problematic. We used hot glue to aid the Weidmuller connectors on the voltage regulator, but it certainly has drawbacks.

I'm a big fan of Alan's PoE idea for this particular problem

[Alan Anderson]

Originally Posted by KrazyCarl92

Which port on the radio supports POE?

Both Ethernet ports on the OM5P-AN support POE, each in a different way. The one nearest the power connector is labeled "18-24v POE", but the bottom of the device says "PoE Input: 12-24V Passive PoE" and it definitely works with the 12 volt output of the VRM. The other connector works with the 802.3af POE standard, which uses 48 volts -- higher than what is permitted by the robot rules.

It's a shame the radio programming kiosk specifies the second port. It would have been handy to use a cheap passive power "injector" and only require teams to connect the Ethernet cable in order to make it work.

[Alan Anderson]

Originally Posted by mwtidd

We used hot glue to aid the Weidmuller connectors on the voltage regulator.

I imagine am certain that a wire properly inserted into a Weidmuller connector will hold more strongly than hot glue.

I just tested it by putting an 18 gauge wire in the +12Vin connection of a VRM, gluing the wire to a scrap of Lexan, waiting several minutes for the glue to harden, then easily pulling it off by lifting the VRM. I did it again with a piece of aluminum. I had no problem holding on to the hardened blob of glue and using the VRM to apply enough tension to pull the wire through the glue.

Most of the wires I saw falling out of Weidmuller connectors were not stripped nearly long enough. It should be 8mm (about 5/16") of exposed conductor.

[philso]

If you have one of the power cables for the radio that has a 90 degree plug (right angle plug), you can wrap a long zip-tie around the radio and the plug. That would be better than gooping up the power plug with hot glue.

[Sohaib]

One common problem (that we had last year) which can lead to temporary power loss long enough to restart your radio is the main breaker. From what I've heard, there are a few every year that have this issue.

Try tapping your finger on the red button on the breaker, (the one you would use to power off your robot) if it causes your robot to power cycle, that's your issue - at least one of them.

[scca229]

Originally Posted by bdaroz

I was going on the basis that our battery voltages were very good (and trending up), and our load was low at the time (and trending down). It was the CSA & FTAs opinion that we lost power completely and the RoboRIO rebooted, however the video of the lights on the RoboRIO (and RSL) didn't concur with that assessment.

Is it possible it was a brown-out, sure, but my point is that there isn't enough data because of the streaming-only nature of the logging mechanisms.

Does that video also show the Radio not losing power and rebooting? How long was the robot down for? What was the RSL doing at the time? A radio reboot is about 50ish seconds and then 10-15 or so more for the roboRIO to attach to the DS.

Do you have a link to the video itself? I'd like to see it for my own knowledge when I'm monitoring the field for my last 3 events this year.

[stoner77]

Not for sure if somone already said this; apparently the breakers that came in some of the kit if parts are bad. Our team had the exact same problem along with a couple others. We didn't know until a team informed us on our last match, we swapped it, then it worked pirfectly. Wiggle the red switch button to test it if all/some of your communications go down.

[Jaci]

We were having this same issue at the Australia Regional. After a while, we narrowed it down to the following 2 things:

a) The Circuit Breaker (and the wire that connects it to the PDP)

b) The Anderson Battery Connectors going from the Breaker/PDP to the Battery's Anderson Connector.

Replacing these seemed to solve our problem for all our future matches. Some breakers can be very sensitive to sudden stops (i.e. crashing into a defense), and faulty Anderson connectors was discussed in another thread.

EDIT: We diagnosed this by looking at the DS. If the comms go down, then comms go up and (later) code goes up (checking DS logs to confirm the signal loss was indeed with the radio), it means the total system did a reboot (radio AND rio), so you can usually diagnose that as the main power feed to the PDP (or the PDP itself), as the RIO and VRM (connecting the radio to power) are on separate connectors.

[Al Skierkiewicz]

OK here goes a list of problems and fixes...
Battery terminals even if tight can be intermittent for a variety of reasons. A simple fix is to add a #10, external tooth star washer between the wire terminal and the battery terminal when assembling the battery wiring. This simple addition will bite through any surface crud on the terminals and lock the two terminals together so that they cannot rotate. Use the provided locking hardware in addition to this one lock washer.
Push the PD fuses all the way in. When properly installed the fuse will be just 1/8" above the PDP surface. It should be hard to remove.
Strip the wires that are inserted into the various Weidmuller connectors to the required length. Often teams make these too short and the result is the wire is not properly retained. Do not tin the wire, these connectors are intended for bare stranded wire. If you pull the wire and it pulls out of the connector suspect the connector. I have seen these damaged by aggressive installers.
A small number (<1 in 100,000) of main breakers have a manufacturing defect. While the robot is on, lightly tap the red button. If your lights flicker, replace the main breaker.
Make sure that the terminals you use to feed the PDP input seats all the way down into the PDP terminals. Some terminals are a little too wide to fit the terminal and will not seat all the way down. This raises the series resistance considerably. Inspect these terminals with a bright light.
Use proper strain relief at each end of the wire. We use self adhesive wire tie blocks or wire tied directly to frame to keep everything from moving around.
This year's radio has antennas behind the vents on either side of the radio. Do not mount your radio near metal objects so that the vents are near the metal objects on your robot.
Observe when your radio reboots. If you have the issue when traversing the defenses, then it is likely a poor connection. If it occurs when turning, then it is a brownout issue.
Never, never, not ever, lift the battery by the wiring. The terminals on the battery are simply soldered in place inside the battery. This is a manufacturing method that allows attaching various terminal styles to the same basic battery. Lifting the battery by the wire will break the solder connection internal to the battery. You will never know you have permanently damaged the battery until you really need it.
I do not recommend hot glue for many reasons. It might give you a false sense of security and will make you look elsewhere when the problem is really under the hot glue all along. If you think about it for a few minutes you can come up with a much better solution.
If you do not use the power plug that came with the radio, then it is very likely you have the wrong diameter plug. They look alike but the center pin varies.

[ollien]

Originally Posted by Sohaib

Try tapping your finger on the red button on the breaker, (the one you would use to power off your robot) if it causes your robot to power cycle, that's your issue - at least one of them.

Oh god this brings back bad memories from a couple weeks ago... At Q31(?) of the NYC regional we had some mounting issues with our top plate. Before we had proper time to fix it, we had to queue up for Q37(?), so we decided to go the match without it. After our partner pushed us out of the moat, our pressure release valve (which was normally mounted to the top plate) swung and hit the red button on the breaker.

That was a sucky way to lose a match, but hey. It happens.

[IKE]

Originally Posted by Al Skierkiewicz

OK here goes a list of problems and fixes...
...snip...

This is a great list, and pretty much the way I trouble shoot robots at competition with "loss of COMMS".

I will also add, Check the Ethernet connection on the laptop. IE, give it a wiggle. I found this was the source of intermittent comms drop for a couple teams at Centerline this past weekend.

This laundry list of items shows why it is such a frequent problem. While the folks at CTRE and NI and FIRST have done a great job at reducing the possible Idiot proofing, there are still so many ways that you can get an issue that low probability of many many things turns into a reasonably high probability that something will get you.

I.E. a 10% chance on any one item, but 10 items with that 10% chance turns into a pretty high probability that something will go wrong.

Pro-tip, when forming your alliance, ask if you can go through your partners robot with a fine tooth comb, and ask them to do the same for you. Often an extra set of eyes can help find issues and errors. Make you own checklists and review them often. Not sure what to put on the list? How about the good advice being dispersed in this thread.

These events the robots are going over are pretty violent. Even the weight of a wire or cable flopping around can be significant when the robot see a 20G pulse (1 lb acts like 20 lbs). Proper restraint and strain relief goes a long way.

[Bruceb]

Originally Posted by Sohaib

One common problem (that we had last year) which can lead to temporary power loss long enough to restart your radio is the main breaker. From what I've heard, there are a few every year that have this issue.

Try tapping your finger on the red button on the breaker, (the one you would use to power off your robot) if it causes your robot to power cycle, that's your issue - at least one of them.

is it possible that the main breaker problem you reference can cause the radio to reboot without the RIO rebooting?
All indications are that our RIO is not rebooting.

[who716]

Originally Posted by Bruceb

We competed at Buckeye this past weekend and suffered comm issues in most of our later matches on Friday and Saturday.
We had lots of folks trying to help us figure it out from the FTA's and other field personnel to mentors from other teams.
Here is what I know.
From looking at logs and reported observations from the FTA's they see the radio rebooting. Immediately after they see the radio return they see the RIO so the belief is that the RADIO is the only think rebooting as the RIO takes longer than the radio and would not show up immediately after the radio if it was also booting.
Even so. The initial thought, before we found out the above, as that we had loos battery connections. We went over all our batteries and did find some that were marginal so we tightened ALL our battery connections regardless if they were loose or not. This did not solve the problem. The problem could not be duplicated in the pit no matter what we wiggled and banged on. We build a practice bot and had no issues with that all preseason. We had the radio from that along so we swapped it in and no joy with that either.
We pulled and re-seated all the wires in the weidmuller connectors on the PDP and VRM and tug tested. Again, no joy. By this time we were past our second match of elims and got subbed out. Not a problem, I would have done the same thing.
Before we bagged we replaced the radio power cable with the one we used on our practice bot and replaced the VRM with a brand new out of the box new one.
Have not had a chance to test since.
Does anybody have any idea what else we should try if this does not work?
Thanks

we had this issue at wpi 2 weeks ago, in all of our qualification matches except for two we lost communication we changed and checked everything, fortunately we were alliance captains, and going into our final quals match we simply decided to move the radio to a different spot and didn't have an issue with it after that something so simply cause suck grief .

[Bruceb]

Originally Posted by Alan Anderson

All the information I needed I found through the OpenMesh web site and a simple search for "passive POE". I summarized it here.

Ok I read that link and I want to make sure I understand how you are using this.
You take a port saver cord, open the cable somewhere and solder a red wire to the blue and white with blue stripe wires and a black wire to the brown and white with brown stripe wires then you stick those wires into the VRM, plug the port saver into the POE port on the radio and the ethernet cable from the RIO into the end of the port saver cable you just modified so you are using only ONE of the ethernet ports on the radio, correct?
Do you cut the wires in the port saver so power only goes to the radio or do you just solder to those wires so power goes to both the radio and the RIO?

Thanks