Safe Method for Purposeful Brown-out

[GeeTwo]

Another oddball way to to this if you don't need too many amps for your test is to set up a motor controller (controlled by an arduino or separate RIO) to provide voltage for the the cRIO. Just don't try to drive it backwards...

[cgmv123]

Originally Posted by GeeTwo

Another oddball way to to this if you don't need too many amps for your test is to set up a motor controller (controlled by an arduino or separate RIO) to provide voltage for the the cRIO. Just don't try to drive it backwards...

I don't know how the RoboRIO will respond to a pulsed output like that of a speed controller, and I'm not sure I want to know.

[AustinSchuh]

Originally Posted by cgmv123

I don't know how the RoboRIO will respond to a pulsed output like that of a speed controller, and I'm not sure I want to know.

Yea, this is a bad idea. One of our mentors connected a motor controller up to another motor controller. The second one blew up pretty fast.

The very low impedance MOSFETs in the motor controller will rapidly switch between 12v and 0v continually. This will cause large, fast, voltage changes across the input capacitors on the roboRIO. That will cause them to heat up and blow up.

[philso]

Originally Posted by GeeTwo

Another oddball way to to this if you don't need too many amps for your test is to set up a motor controller (controlled by an arduino or separate RIO) to provide voltage for the the cRIO. Just don't try to drive it backwards...

Inverters + Wiring Inductance = Voltage Spikes

It would be best to use an oscilloscope to look at the motor controller output, with the intended wiring, to ensure that you are not getting voltage spikes that go higher than the rated input voltage or go below zero volts.

In the past, I have used programmable DC power supplies that can simulate a brown out condition but they were pretty expensive.

The brown out test would be more repeatable if one used a MOSFET with a power resistor to add a momentary high-current load to your system. An oscilloscope would have to be used to measure the system voltage.