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-   -   Blown talon srx modules (http://www.chiefdelphi.com/forums/showthread.php?t=134069)

Ether 02-09-2015 11:06 AM
Re: Blown talon srx modules
 

If P2 is the maximum mechanical power you can draw from a CIM's output shaft for a given input electrical power P1,

and P3 is the maximum electrical power you can draw from a CIM whose output shaft is being driven with mechanical power P2,

then P3 is considerably less than P1.

Reason: motor losses work in both directions.

Alan Anderson 02-09-2015 12:19 PM
Re: Blown talon srx modules
 
Quote:
Originally Posted by GregGarner (Post 1440577)
We think that a combination of extremely dry conditions (i.e. no humidity) and assembling in a carpeted room may have contributed.
Dry air, carpet, and electronics are not a good combination. I think your best remediation will be using an anti-static mat to cover the carpet. Wrist straps will help a lot, but I am confident that they will not always be used when appropriate.

philso 02-09-2015 01:10 PM
Re: Blown talon srx modules
 
Quote:
Originally Posted by GregGarner (Post 1440597)
The current theory is ESD on assembly.

If you are skeptical of this, then given the evidence, what is your theory?
I am certainly open to other theories, as my main goal is to figure this out and stop the bleeding!

Here is a quick summary:

1) 2 blown talon SRX devices when working on the robot, may or may not have been moving the motor (we just didn't notice exactly when they stopped working). These 2 were on different motors, and did not blow at the same time. When we replaced the talon we did not change any wiring or any motor, and the talons that were replaced are still working fine. The Talon SRX devices have no LED after they are blown, i.e. the CPU and the regulator were fried. These two were looked at by CrossTheRoadsElectronics and found multiple chips were fried (just nonworking and shorted, the tops were not blown off the chips).

2) 1 more blown Talon SRX, this one apparently went out while we were moving the motors manually, and it may have been powered or not powered on by the battery, not sure. Again the sympton is the LED does not come on at all. Changed the Talon, did not change anything else, replacement Talon is still functioning. This one has not yet been returned for post mortem.

3) Final Talon SRX blown when moving a bag motor. I will verify the symptoms (i.e. no LED) this evening, as I haven't seen it in person yet.
This one has not yet been returned for post mortem.

Note that we are using the PD board with circuit breakers, and we are using a standard FRC battery. This robot has been very carefully assembled, we did not connect up the Talon SRX modules backwards or get the battery polarity backwards. All connections were done with solder, covered by heatshrink (although we are switching back to high amperage connectors now because we suspect we may have to change out Talons in between matches if we can't solve this problem)



GregGarner
3612 Gearhogs

Were the chips that CTRE found to be damaged connected to "the outside world" or were they only connected "internally"? The ESD would have been amazingly powerful to cause damage past the first device it hits. ESD can cause mis-operation of a device when injected into the system while it is running but I doubt that you would be touching those connections while running your robot.

Perhaps CTRE may want to check their supply chain for counterfeit parts. We have had several instances at work where counterfeit parts sort of work but caused failures where there was no "abuse" of the system.

JamesBrown 02-09-2015 01:31 PM
Re: Blown talon srx modules
 
Quote:
Originally Posted by philso (Post 1440690)
Perhaps CTRE may want to check their supply chain for counterfeit parts. We have had several instances at work where counterfeit parts sort of work but caused failures where there was no "abuse" of the system.
I would be surprised if this was a component issue, if it was I imagine the problems would be much more wide spread.

mklinker 02-09-2015 09:04 PM
Re: Blown talon srx modules
 
Quote:
Originally Posted by JamesBrown (Post 1440714)
I would be surprised if this was a component issue, if it was I imagine the problems would be much more wide spread.
We have had two Talon SRX controllers drop from the Can network after working for a day or longer each and then complete turn up dead......no signal lights ..... Not on the network....: just dead with after being fully functional. I have not contacted CTRE yet but will.

Michael Hill 02-09-2015 10:09 PM
Re: Blown talon srx modules
 
Quote:
Originally Posted by Alan Anderson (Post 1440647)
Dry air, carpet, and electronics are not a good combination. I think your best remediation will be using an anti-static mat to cover the carpet. Wrist straps will help a lot, but I am confident that they will not always be used when appropriate.
I'm sure we differ in opinions, but I've always felt that any piece of consumer electronic that can be permanently destroyed by ESD is, to put it bluntly, crap. Also, odds are not many teams even have ESD mats and wrist straps and even fewer have them connected correctly. A product that is designed to be put on FRC robots should take carpet, dry air, high school students, heck mentors, into consideration. It's pretty inexcusable for a product used in this environment to be affected, especially permanently, by ESD.

Alan Anderson 02-09-2015 11:25 PM
Re: Blown talon srx modules
 
Quote:
Originally Posted by Michael Hill (Post 1441012)
I'm sure we differ in opinions, but I've always felt that any piece of consumer electronic that can be permanently destroyed by ESD is, to put it bluntly, crap.
We agree on that part. However, I don't consider Talons to be "consumer electronic" devices.

Michael Hill 02-10-2015 05:43 AM
Re: Blown talon srx modules
 
Quote:
Originally Posted by Alan Anderson (Post 1441045)
We agree on that part. However, I don't consider Talons to be "consumer electronic" devices.
They are, however, a device that are designed with this specific purpose in mind, which should require it to have even better ESD protection.

wireties 02-10-2015 08:26 AM
Re: Blown talon srx modules
 
Quote:
Originally Posted by Michael Hill (Post 1441012)
I'm sure we differ in opinions, but I've always felt that any piece of consumer electronic that can be permanently destroyed by ESD is, to put it bluntly, crap.
And what "consumer electronics" come with bare wires to which you must connect power and or signalling cables?

Being aware of ESD and taking care not to zap electronic components is SOP and good things for students to learn. A better question is were they warned by the packing material or by a mentor? I don't remember seeing anything in the TalonSRX manual, a pretty big oversight. But all the electronics used in FIRST can be damaged by ESD (to some degree) - I warned our guys/girls just the other day to NOT touch the gyro board as it is really easy to zap and destroy.

2457 The Law 02-10-2015 10:32 AM
Re: Blown talon srx modules
 
We also have a blown Talon SRX. During a practice session last weekend the talon stopped functioning. No lights no voltage on the output leads at all. We opened the talon and discovered that one of the capacitor leads to the circuit board was burned into. We soldered the lead back together but still does not work. Looks like something else on the board is fried. The only thing we think might have happened is the connectors on the leads from the talon to the motor were not correctly insulated and shorted to the aluminum frame. The beaker on the power distribution board was tripped.
We have ordered two more. It seems as though the new Talons are somewhat sensitive. Word of caution, make sure all connectors are secure and insulated properly and have a couple of spare talons on hand.

Michael Hill 02-10-2015 12:05 PM
Re: Blown talon srx modules
 
Quote:
Originally Posted by wireties (Post 1441154)
And what "consumer electronics" come with bare wires to which you must connect power and or signalling cables?

Being aware of ESD and taking care not to zap electronic components is SOP and good things for students to learn. A better question is were they warned by the packing material or by a mentor? I don't remember seeing anything in the TalonSRX manual, a pretty big oversight. But all the electronics used in FIRST can be damaged by ESD (to some degree) - I warned our guys/girls just the other day to NOT touch the gyro board as it is really easy to zap and destroy.
Home Theater equipment, for one. But regardless, the wires didn't even have to be like that. It could have been some kid of female receptical (something like powerpole).

I'd like to see some high resolution pictures of the blown boards to see if there's anything in common.

Mike Copioli 02-10-2015 12:48 PM
Re: Blown talon srx modules
 
Quote:
Originally Posted by Michael Hill (Post 1441129)
They are, however, a device that are designed with this specific purpose in mind, which should require it to have even better ESD protection.

Better than What? Do you even know what the ESD rating is for the Talon SRX?
This would be an important thing for you to know before claiming it is not sufficient.

Mike Copioli 02-10-2015 12:51 PM
Re: Blown talon srx modules
 
Quote:
Originally Posted by 2457 The Law (Post 1441208)
It seems as though the new Talons are somewhat sensitive. Word of caution, make sure all connectors are secure and insulated properly and have a couple of spare talons on hand.
Sensitive to what?


Have you contacted CTRE support regarding this issue?

Mike Copioli 02-10-2015 01:08 PM
Re: Blown talon srx modules
 
We have been working with Greg and will continue to work with him on this issue. This problem has never been reported or observed during Internal testing or during Beta testing. We will continue to work with him and any team that has an issue with a Talon SRX.

Due to the nature of symptoms and information provided during conversations with Greg, I believe the issue is unique to this particular robot configuration. Possibly related to the cabling strategies between the encoder and the data port.

Since this problem cannot be repeatedly reproduced, pinpointing the exact cause is difficult. If any team is experiencing a similar issue, please contact support@crosstheroadelectronics.com to report.

Michael Hill 02-10-2015 02:09 PM
Re: Blown talon srx modules
 
Quote:
Originally Posted by Mike Copioli (Post 1441266)
Better than What? Do you even know what the ESD rating is for the Talon SRX?
This would be an important thing for you to know before claiming it is not sufficient.
Seeing as the data has not been released (that I have seen), of course I don't know what it is. I would expect it should be on the order of 15kV. Anything less than 8kV, I would say is probably insufficient for this application.


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