There is a potentiometer vane and the diagram includes protection components and looks messy, I simplified it by re-drawing as below:
The circle R1, R2, R3 and the gap represents the vane's 10k potentiometer section. The datasheet says "Wiper Contact Resistance" is 400 Ohm, so I modelled it as Rwp. Rw resistances above represents the wire resistances for the red and blue wires which passes the supply current. Rs is the possible supply output resistance.
It is clear to me that Ch1 and Ch3 measures the potential difference between the point X and point Y. This is called I guess Kelvin connection. Ch2 is the poti output so the ratio Ch2/(Ch1-Ch3) can be obtained which corresponds to angle. I want to calibrate this by using an encoder versus this ratio.
The vane has a dead band. Now for the this dead zone the datasheet suggests a pull down/up resistor RL between Ch3 and Ch2 but it doesn't mention or suggest any value. My question is what could be the reason RL is tied between Ch2 and Ch3 but not between Ch2 and the ground? And what value for RL can be reasonable?