Structure and Application of Heidenhain Encoder 733426-01

Structure and Application of Heidenhain Encoder 733426-01

We usually use incremental encoders, which can directly input the output pulse signal of the rotary encoder to the PLC, and use the PLC's high-speed counter to count its pulse signal to obtain measurement results. Different models of rotary encoders have different numbers of output pulses. Some rotary encoders output three-phase pulses of A, B, and Z, some only have two phases of A and B, and some only have phase A.

High speed end installation: Installed on the shaft end of the power motor (or gear connection), this method has the advantage of high resolution. Due to the 4096 turns of the multi turn encoder, the number of motor rotations within this range can be fully utilized to improve resolution. The disadvantage is that there is gear clearance error in the back and forth travel of moving objects after passing through the deceleration gear. It is generally used for one-way high-precision control positioning, such as roll gap control in steel rolling. In addition, the encoder is directly installed at the high-speed end, and the motor vibration must be small, otherwise it is easy to damage the encoder.

Low speed end installation: Installed after the reduction gear, such as the shaft end of the winch wire rope drum or the shaft end of the section reduction gear, this method has no gear backlash, and the measurement is more direct and accurate. This method generally measures long-distance positioning, such as various lifting equipment, feeding trolley positioning, etc.

The encoder has 5 leads, including 3 pulse output lines, 1 COM terminal line, and 1 power line (OC gate output type). The power supply of the encoder can be an external power supply or directly use the DC24V power supply of the PLC. The "-" end of the power supply should be connected to the COM end of the encoder, and the "+" end should be connected to the power supply end of the encoder. The COM end of the encoder is connected to the input COM end of the PLC, and the A, B, and Z phase pulse output lines are directly connected to the input end of the PLC. A and B are pulses that are 90 degrees apart, and the Z phase signal has only one pulse when the encoder rotates once, usually used as a basis for zero point. When connecting, attention should be paid to the response time of the PLC input. The rotary encoder also has a shielded wire, which should be grounded during use to improve anti-interference performance.

Due to the 90 degree difference between phase A and phase B, the forward and reverse rotation of the encoder can be determined by comparing whether phase A is ahead or phase B. By using the zero position pulse, the zero position reference position of the encoder can be obtained. The materials of encoder encoders include glass, metal, and plastic. Glass encoders deposit very thin engraved lines on glass, which has good thermal stability and high accuracy. Metal encoders directly engrave lines with or without lines, which are not fragile. However, due to the thickness of metal, the accuracy is limited, and its thermal stability is one order of magnitude worse than that of glass. Plastic encoders are economical and have low cost, but their accuracy, thermal stability, and lifespan are all inferior.

Resolution - The number of lines provided by an encoder for each 360 degree rotation is called resolution, also known as resolution division or directly referred to as number of lines. Generally, it ranges from 5 to 10000 lines per rotation.

Structure and Application of Heidenhain Encoder 733426-01