Monitoring device and monitoring method for rotary encoder

摘要

Problem: To provide a monitoring device and method for a rotary encoder that can detect abnormalities of the encoder from only the output signals of one TTL rotary encoder Means to Solve the Problem: A monitoring device 1 includes: XOR circuits 32A, 32B; delay circuits 33A, 33B; frequency multiplying circuits 35A, 35B; and determining units 36A, 36B. The frequency multiplying circuit 35A and the XOR circuit 32A generate a comparison pulse signal that is compared with a B phase signal. By comparing the B phase signal and a comparison pulse signal, the determining unit 36B determines whether a phase difference between an A phase signal and the B phase signal is within 90° ± 30°. Similarly, the frequency multiplying circuit 35B and the XOR circuit 32B generate a comparison pulse signal that is compared with an A phase signal. By comparing the A phase signal and the comparison pulse signal, the determining unit 36A determines whether a phase difference between the A phase signal and the B phase signal is within 90° ± 30°.