Technical Description: Rheostat: Notes

Fig 1: Rheostat Communication Diagram

Courtesy of SAAB-SCANIA OF AMERICA, INC.

Fig 2: Rheostat Circuit Diagram

Courtesy of SAAB-SCANIA OF AMERICA, INC.

The rheostat supplies the SID unit with information on the driver's choice of rheostat setting.

The rheostat is a potentiometer which is supplied with +5 V via pin 11 of the control module. The rheostat is grounded through pin 4.

The voltage across the integral rheostat in the SID unit is proportional to the actual resistance of the rheostat, see diagram. The SID unit uses this value to control the button lighting and calculate the display lighting level.

Information on the rheostat level is sent as bus information, Rheostat level, unit (%).