How to use encoders

[ozrien]

Hey Chris,
Since you are using the Talon's sensor features I would start by looking at our Talon SRX software reference manual...
http://www.ctr-electronics.com/talon...ical_resources

Section 2.4 goes over the roboRIO web-based config which is an easy way to get the sensor value so you can sanity check the position/velocity. This works even with no code deployed because the Talon is always decoding sensor signals. Also the web page lets you set settings without having to write code, which is great for getting started and quick tweaking. All the settings in the web page are persistent.

Section 5.1 has a LabVIEW example on un-bundling signals including Sensor Position and Sensor Velocity.

Section 7.1 has a LabVIEW example on selecting the sensor type, be sure to direct the sensor to be in phase with the motor if you want to use the internal closed-loop features (section 7.4).

Section 13 has examples for setting the sensor position, great for zero-ing all your sensors.

Section 16.9 has some good stuff on processing the sensor data yourself if you don't want to the Talon to closed-loop for you. You can control how fast the Talon sends sensor pos/velocity to the RIO so you can choose how much you want to offload to the Talon. This is neat because each Talon effectively gives you an additional 1x analog input, 1x quad input, 2 digital inputs (you can use limit switch inputs just for measurement if you want), and 1x pulse width decoder.

The sensor position and velocity were all in native-units last season, which is explained in section 17.

Scott's mentioned example is a good one too. Has the PIDF gains broken out in a VI for easy tweaking.