Battery Display on DS

In the rules it states that we have to have the battery connected to the analog break out.

[quote=<R64>]A National Instruments 9201 module must be installed in slot 1 of the cRIO Mobile Device
Controller. An analog breakout must be connected to this module. A jumper must be
installed on the “Battery Voltage” and “Power” pins on the analog breakout. The analog
breakout must be powered from the Power Distribution Panel. Please refer to Section 3.4 of
the “FRC Control System Component Data Sheets” for information on these connections. [/quote]

and then it refers to this

Now here is the problem. Is the battery voltage suppose to show up next to “Battery” on the DS? We have done all these steps and it still says 00.00v but then when we read the analog input of AI8 it comes up as 7(ish)v which is about 40% of the 12v(as stated in the Q&A right below).

Spent a good amount of time searching, but didn’t find anything that was really relevant to this.

Wow, this is a really good point. I’m sorry I dont know how to help, but in reading this I realized that we have had the same problem… I think… I will check on the robot tonight to see how ours is and let you know if we got it to work…

I thought the resource reservation system wouldn’t allow you to get clean access to AI8:1. How are you accessing this data?

What else is the Driver Station displaying? Enabled/Disabled/No Comms/No Code? What about the RSL state?



We have done all these steps and it still says 00.00v but then when we read the analog input of AI8 it comes up as 7(ish)v which is about 40% of the 12v(as stated in the Q&A right below).

7(ish) is not 40% of 12.

Are you certain you have battery power coming from the Power Distribution to the Analog Breakout? Measure on the white WAGO connector on the breakout to make sure. You might have one of the WAGO connections hitting the insulation instead of the conductor on an insufficiently-stripped wire.

(Note that you must use a 20A breaker, not a 5A one.)

Yes, we do have power going to the breakout via a 20amp breaker.

Enabled, displays No Comms No Code when it first starts up then goes to 00.00v and stays. Does the same thing with autonomous enabled. We have been been running programs on the cRIO since the start of the season. Everything is updated and what not. I just noticed that this was happening the other night and couldn’t find anything about it.

Note – We have been changing out the battery and no change.

Does the DS ever change to not show “no comms” or “no code”?

I’m suspicious about whether you’re using the templates and initiating the system as required. Have you followed the very detailed step-by-step procedures to bring up the system from the OTB condition?

What about the RSL state?


You may have a problem with the analog bumper, try swapping out the one you have connected. I know this worked for another team.

Is the power LED on the Analog Breakout lit?


We also cannot seem to get the battery reading working. Honestly, it’s been low on our list of things to do for awhile, but tonight I’ll take a look and try to figure out what’s going on.

We did RTFM. I’ll try the other bumper tonight.

Ours has been working fine. I’d suggest looking again at Alans ideas above…

Sometimes a picture helps. With the following connections and default code loaded the battery voltage should should be displayed on the DS.


batt voltage.pdf (283 KB)

batt voltage.pdf (283 KB)

It reads ~7ish volts because the input range on the cRIO AI module is -10V to 10V. So there is a voltage divider on the analog bumper input 8 to bring battery voltage down within this range. The cRIO software knows this so it reports the actual battery voltage after it does the math to undo the voltage division.

I’m also having a similar problem. the system boots up and the voltage reads 0.00v. I’m not sure what to do because I have followed all the instructions discribed. It’s getting really close to our first competion and i’m getting nervous that it’s not working. Can some please reply if you have figured out this problem.