My team is using a brand new roboRIO 2.0 and last week we tested different ports and pins with a multimeter to find the power fault or short in it since the power LED was solid red. We found that the TXD pin on the RS-232 port is connected to the ground and supplies an uneven 9.5-ish volts. Is the RIO supposed to do that? We used the beep thing and touched the black lead to a ground pin and the red lead to the TXD pin. There is no obvious debris or shorting that can be seen when we opened it up. We also blew off the board to see if it would help (it didn’t). The roboRIO 1.0 does not do that. Any advice would help, thanks!
It’s within spec for the TXD pin
“…A high level for the driver output is defined as between +5V to +15V, and a low level for the driver output is defined as between -5V and -15V.”
My roboRIO 1.0 RS232 TXD gives the same -9.73v as my roboRIO 2.0
By uneven, I mean that it is -9.5 plus or minus 0.5 volts.
But on the beep test on a multimeter, does the ground and that pin beep? That’s what I’m stumped about.
It should not beep with a continuity test between the TXD and the ground on the RS-232.
But it also cannot give you a -9.5v reading between those two pins if they are indeed connected.
I suspect your meter or how the probes are touching.
I’d try with a different multimeter to compare.
This topic was automatically closed 365 days after the last reply. New replies are no longer allowed.