What do Analog Enocders Connected to a TalonSRX Return?

Technical Programming
1

Hi we’re thinking about using the MA3 Analog Absolute Encoders this year. If i were to call getSelectedSensorPosition() what would it return? A voltage 0-5? 0-3.3? Or will it convert the signal into a 10 bit number between 0-1024?

If it is a voltage how would using the velocity control on the talon differ? Thank you for the help in advance

1 Like
2

The talon converts an 0-3.3v analog signal to a 10 bit number (0-1023). If you are using the analog breakout board, it has an analog voltage divider to scale 5v to 3.3v, so 5v becomes 1023. The talon then wraps the 10-bit number to account for sensor rollover - so going from 1023 to 0 actually reports 1024, and continuing to go forward results in a number that continues to count up. The talon then uses this 10-bit wrapped position as the position and the derivative of that as the velocity for control purposes.

3

Is the breakout board necessary or is that conversion function built into the talon itself?

4

The breakout board changes the analog range.

The talon itself has a 3.3v analog to digital converter (0v = 0, 3.3v = 1023). If your sensor outputs 3.3v you can connect it directly to the Talon.

The breakout board has a voltage divider which scales 5v to 3.3v (0v = 0, 5v = 3.3v). If your sensor outputs a 5v signal (which the MA3 does), you will need the analog breakout.

5

Got it thank you so much

6
  • The AM breakout will support both an analog and a quadrature encoder with no soldering required.
  • The CTRE breakouts will support one or the other, but pad soldering is necessary.
  • The Talon SRX actually supports both, and if you want to use both without getting anything from AM, you can alternately (and much less expensively) get CTRE’s Gadgeteer breakout, which will support both, but require a bit more creative wiring on your part. It requires through-pin soldering.