We currently are using the CTR Mag encoders to position ourselves. Is it possible to have these mag encoders be able to remember their last position when it was turned off? And can it also be able to track the position when the robot is off? I have looked into setting them as relative or absolute and both currently seem to be initialized to a garbage value until zeroed. If anyone can provide any insight that would be great.
They do remember their position between the robot turning off and on, but only within a single rotation of the encoder. It cannot track position when the robot is off however, so if you turn it more than 1 rotation while off you lose the information of its last position. The initial value when it is turned on isn’t a garbage value, but the current position of the encoder within its rotation. It works kind of like an encoder with a marker signal every rotation.
When the encoder turns on, it “zeroes” the rotations it has turned so the starting value will always be between 0 and 4096 (or -4096 if you negate the direction) units.
One thing that I am not sure about but would like to know is that it seems like zeroing the encoder in absolute mode is persistent across power cycles, like it is just saving some adjustment value on the TalonSRX. Is that the difference between the CTRE mag encoder “relative” and “absolute” modes, absolute just saves zeroing across power cycles?