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[HELP] Digital Sidecar troubles
We've managed to isolate our problem to our sidecar. After that, our team is completely lost as to what the problem is. We've switched through some sidecars but none seem to work, so it may be something wrong with the set up. Nothing electrically has changed between when we last competed, CTTD 11/3/12, and now. Our sidecar is set up, but suddenly the 5v and battery light are spazzing out. As well, we only sporadically get power to the RSL. Any suggestions? The lights are fine when we're disabled, but once we enable then all the spastic problems start happening. We've gone through and checked for shorts, but didn't find any.
EDIT: Also, we're getting a high pitched whine from the PDB...any ideas on that, and if it's an issue? We do have a replacement PDB but we'd rather not have to replace it if we don't have to. |
Re: [HELP] Digital Sidecar troubles
Every sidecar problem we ever had was caused buy the cable and not the sidecar.
Check the cable. |
Re: [HELP] Digital Sidecar troubles
Sounds like you have power problems, check that all the fuses are good and if the wago connection is not loose (the cords tend to slip out over time). Also, I'd check to see if the cable from the cRIO to the Sidecar is fine, since the robot's game state seems to have an influence, although I don't think that's the problem since you say it worked in CTTD and hasn't changed since.
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Re: [HELP] Digital Sidecar troubles
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Re: [HELP] Digital Sidecar troubles
We've also found the ribbon cables to be finicky.
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Re: [HELP] Digital Sidecar troubles
We've had this problem quite a bit. For us it's been caused by a digital I/O or PWM connector being shorted out. You should try running the robot with nothing connected to the sidecar, then add the connections until you find the bad one. We've found that it's quite easy for the DIO cables to get damaged and short together and cause the 5V supply on the sidecar to drop out. We've also seen a very similar problem to this where all of the outputs on the sidecar drop out. This is caused by the 9403 digital module losing power. If your cRIO power connector is loose, it can cause the digital module(the part that goes in the cRIO, not the sidecar) to brown out when the rest of the cRIO doesn't.
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Re: [HELP] Digital Sidecar troubles
A few thoughts that might help diagnose the issue:
- unplug the DSC and hold a multimeter up to the plug. Read the voltage when the robot is both enabled and disabled. Please make sure you do so safely! This should mimic the battery voltage, so it won't hold steady at 12V. - Even if you don't have a short, you could have an open circuit. I saw a team at an off season competition a month or two ago that used 22 gauge from the PDB to the DSC, and managed to burn it out completely - broken wire, burned/melted insulation... it was ugly. With a broken wire, you could see intermittent operation. - Remove all the breakers from the PDB except those required for the DSC and the analog breakout board. Do you still hear that whine? Do you still see the incorrect behavior on the DSC? If not go through replacing the breakers one at a time - at some point you'll start encountering your issues again, but this may give you a different place to look. - Are there any red LED's on beneath any of ports on the DSC? Those are there to tell you if there is an issue (a short) with that port! |
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Re: [HELP] Digital Sidecar troubles
If you try the suggestions here, still can't find the problem, and you'd like some on-site help, PM me. My schedule isn't too horrible this month, so we can probably find a mutually agreeable time for me to visit your shop and take a look.
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Re: [HELP] Digital Sidecar troubles
I remember seeing Joe Hershberger (jhersh) diagnosing a problem at the Alamo regional once that mystified all present. On your list of things to check please add the following:
The pins on the DSub connector on the cRIO may get bent if the module is not inserted correctly. It is unusual, but I've seen it happen twice now. Depending on which pin is bent, the module may power up and report fine, but may not function properly. |
Re: [HELP] Digital Sidecar troubles
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Re: [HELP] Digital Sidecar troubles
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Now, for the whine. Is it high pitched or low? It is either the sound made by the constant tripping of a circuit breaker or an audible harmonic emitted by one of the switch-mode power supplies in the PDB (5, 12, or 24V). Also note that the sidecar and the analog breakout also have switch-mode supplies in them too, so be sure that the noise isn't coming from a sidecar next to the PDB and you're just assuming it is the PDB. The sound of a circuit breaker constantly tripping will (in my experience) makes a lower pitched noise. The sound of the switch-mode supplies will be higher pitched and may change frequencies based on the current being drawn. This may be caused by the most popular robot construction sin -- metal debris in the electronics. To isolate whether it is the switch-mode supplies rather than a circuit breaker, you can remove all circuit breakers to see if it is the PDB, and then start adding one back at a time as others have suggested. Since the failure didn't go away after changing sidecars, I doubt that the sidecar is the issue. And I doubt that it is a bent pin since I can't think how the loss of connectivity would generate a whine. |
Re: [HELP] Digital Sidecar troubles
I know the sound of a constantly tripping circuit breaker. It isn't that noise. It's a high pitched squeal (Or whine as my girlfriend called it). Our sidecar is fairly remote from our PDB (a good 18"-24"), so I don't think it's the sidecar.
As far as clarification as to why we believe it's somewhere along the line of the sidecar, or perhaps the DB37 cable, would be that it we are still able to enable the robot, get spotty control of the robot, and then we die out. We tried switching the port the sidecar gets power from and still have the same problem. |
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Re: [HELP] Digital Sidecar troubles
Does the power board continue to whine when unloaded? Meaning if you pull all the connections and energize the board do you still hear it make noise? This would mean removing *all* the breakers, disconnecting the radio, cRio, and camera (basically having an empty board). After it is disconnected, power the PD board up from the battery and see if you still have the whine.
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