Using Encoders with TalonSRX

[Chaube97]

Ok, I just thought set() was something else that applied to CANTalon modes and PID control. I figured out that the set() values in speed mode go from 0 to 1000. Everything works now. Thank you so much for your help!

[ozrien]

Originally Posted by Chaube97

I figured out that the set() values in speed mode go from 0 to 1000. Everything works now. Thank you so much for your help!

Well...wait....it sets the target speed in pos per 100ms, which can be negative (reverse) and can be larger than 1000.

So do you see how in section 17.1 (Talon SRX software reference manual) the example math for a CPR=360 quadrature encoder calculates a speed of 28800 for 20 rotations per second (or RPM=1200)? So set(28800) would servo a velocity of 1200RPM in the positive direction IF using a quad encoder (that's CPR=360).

Make sense?

[Chaube97]

Ohhh. Our encoder is the E4P-250-250-D-D-D-B. I don't know the CPR, is it 250? If we set the speed to 500, the encoder reads a velocity of 300.

[Ether]

Originally Posted by Chaube97

Ohhh. Our encoder is the E4P-250-250-D-D-D-B. I don't know the CPR, is it 250?

Yes.

If we set the speed to 500, the encoder reads a velocity of 300.

What value is the Talon reporting for the setpoint-process_variable error?

[Chaube97]

Thanks! How many rotations would the encoder have then? I don't know where to find the setpoint-process_variable error, but the ClosedLoopError variable in the self-test section is 200. The motor not going 500 is probably a result of me messing with the PID variables. I was changing the P variable around to see the ocsillation and other things. The motor goes a velocity of 300 when my P = 1.5, and my I and D equal 0.