We are getting a number of 5v brownout messages in our log file. I am told the correct interpretation is that it is the internal 5v rail browning out, not the robotrio (which continued with no obvious side effects). The roborio specs documenting current limits is here.
https://decibel.ni.com/content/docs/DOC-30419.
The Roborio uses 5v for a number of items including the 5v PWM outputs, DI/O, Analog Input. We have a lot of motor controllers (10), 4 encoders, 3 light sensors and 1 ultrasonic sensor. We have carefully checked the 0.1" connectors for loose strands etc.
There appears to be no relationship between vibration and the messages (we dropped our robot from 6" a number of times with no messages).
Anyone with expert specific knowledge (maybe from NI) confirm
1) Are we interpreting the message correctly
2) Could we possibly be at the current limit of the 5v rail with the above configuration operating correctly or not likely ?
3) Any obvious diagnostics ? I suppose we could measure the current on each I/O connector and sum them ?
Difficult? Yeah.
Extremely difficult? Some parts.
Doable? It's been done. - [more] 
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