Monitoring system for electrical angle calculator

A monitoring system for a microcomputer that calculates an angle of a rotator, comprising:

• a motor for driving said rotator;
• a rotation angle sensor for detecting an angle of said rotator;
• said microcomputer which includes:
• angle calculator means for calculating the angle of said rotator based on an excitation signal provided for said rotation angle sensor and an output signal from said rotation angle sensor;
• and
• control signal generator means for generating an electrical control signal that indicates a first angle range to which the angle calculated by said angle calculator means belongs;
• supervisory signal generator means for generating an electrical supervisory signal that indicates a second angle range to which the angle detected by said rotation angle sensor belongs based on an intermediate signal obtained as a result of multiplying the angle detected by said rotation angle sensor by the excitation signal provided for said rotation angle sensor;
• comparator means for comparing the first angle range indicated by said control signal with the second angle range indicated by said supervisory signal;
• and
• fault detector means for determining that a failure occurs in said microcomputer when said comparator means determines that the first angle range disagrees with the second angle range.