ROTARY SPEED DETECTION DEVICE WITH ERROR MONITORING

摘要

The present invention discloses a speed and movement direction sensing device. The sensing device includes an incremental encoder, which generates three pulses shifted by about 120 (electrical) degrees. A speed signal generation section receives the encoder signals and generates a pulse signal, which frequency is proportional with the frequency of the input signal. The encoder self-test section monitors the encoder states and detects encoder error based on the encoder signals and a direction detection section generates a direction signal based on the encoder pulses. The sensing device allows encoder self-test even in case of zero speed. The fault-tolerant speed and movement direction sensing device offers a higher reliability than the prior art and can be applied in motion control systems where high safety and integrity level is required.