Servo Example on LabVIEW -- assistance, please.

Our programming team spent a couple hours yesterday trying to get the LabVIEW servo example working. Has anyone had success with driving servos in this environment and would be willing to ask/answer some specific questions about our setup? (i.e. help out our programmers?)

The students will be starting up again today about 1PM Central time today ( Jan 17th) and we would appreciate any experienced, knowledgeable assistance.

In the meantime, any assistance pointing towards a solution on the CD or NI websites would be appreciated.

FYI – We’ve had absolutely no issues with victors, DIO, analog sensors, etc. Just can’t seem to get the servo to work. Oh, and yes – we are sure there is a jumper and we know that the servo is getting power (and otherwise appears to work). Also, I’m planning to bring in a little VEX setup to verify that the servo does work properly (rule out HW/logic issues with the servo unit itself).

Much obliged.

One diagnostic is to try manually turning the servo shaft. If the servo has power, it will resist disturbances and return to the previous state; telling you that the breakout, jumper, and other electrical elements are working. Also, unplugging the PWM, rotating the shaft to a new location and replugging the PWM, you should see the servo going back to the same position.

If these work as expected, it is a SW issue. It may be useful to see what value the servo is moving to. If pegged on either end, it could be a units issue. I believe there used to be two servo units, an integer input meaning degrees, and function took 0 to 1. Vary the input to the servo function anyway and see if any of them work.

Greg McKaskle

(avoiding the creating of another thread)

If you took one of the examples in the Labview FRC examples folder, like servo, digital I/O, etc, you should be able to :

a) connect a crossover lan cable from the labview pc to the cRio
b) configure the labview pc with an address
c) configure the cRio appropriately and with an address
d) load the servo or dio project, and configure the target ip address

and hit the run arrow at the top of the VI

right ?

And the screen dialog interact with the user ?

We are going to try that in a couple of hours.

Sounds good.

You will also need to have the Driver Station running on your LabVIEW PC to enable the robot.