The role of rotary encoder to measure the principle of motor speed

The function of the rotary encoder The principle of measuring the speed of the motor The function of the rotary encoder is to measure the speed of the motor. The speed measurement signal of the rotary encoder can be transmitted to the frequency converter or the PLC. It is mainly used in the occasions where the motor speed is relatively high. Absolute encoders can not only measure the speed of the motor, but also "memorize" the stop position of the motor. The absolute encoder is more advanced than the incremental encoder, and the price is much more expensive.

The signal output of the rotary encoder has sine wave (current or voltage), square wave (TTL, HTL), open collector (PNP, NPN), and push-pull multiple forms. TTL is a long-line differential drive (symmetrical A, A-; B, B-; Z, Z-), HTL is also called push-pull, push-pull output, the signal receiving device interface of the encoder should correspond to the encoder.

Signal connection-The pulse signal of the encoder is generally connected to a counter, PLC, and computer. The modules connected to the PLC and the computer are divided into low-speed modules and high-speed modules, and the switching frequency is low or high.

Such as single-phase connection, used for single direction counting and single direction speed measurement.

A.B two-phase connection, used for forward and reverse counting, judgment of forward and reverse and speed measurement.

A, B, Z three-phase connection, used for position measurement with reference position correction.

A, A-, B, B-, Z, Z- connections, due to the connection with symmetrical negative signals, in the subsequent differential input circuit, the common mode noise is suppressed, and only useful differential mode signals are taken, so its resistance It has strong interference capability and can transmit over long distances.

For TTL encoders with symmetrical negative signal output, the signal transmission distance can reach 150 meters.

The rotary encoder is composed of precision components, so when it is subject to a large impact, the internal function may be damaged, so full attention should be paid in use