Choosing the right encoder for your motor requires consideration of several factors, here are some key points:
1.Determine the encoder type
Incremental encoder: generates pulse signals by measuring the angle of rotation of the shaft, which has the advantages of simple structure, low cost, high resolution, etc. It is suitable for the occasions that need to measure the rotational speed, position change, etc., such as machine tools and automated production lines.
Absolute encoder: It can directly give absolute position information of the shaft and maintain position memory even after power failure, suitable for applications requiring precise position control and positioning, such as robots and lifts.
2.Consider resolution requirements
The resolution of the encoder determines its measurement accuracy. Generally speaking, you need to select an encoder with the right resolution according to the application scenario and precision requirements of the motor. For example, for high-precision CNC machine tools, it may be necessary to choose an encoder with a higher resolution, such as several thousand pulses per revolution or even higher; while for some common industrial motors, a lower resolution encoder may be able to meet the requirements.
3.Matching the electrical interface
The electrical interface of the encoder needs to be matched with the control system of the motor, and the common interface types are TTL, RS422, SSI, Profibus - DP, CANopen and so on. For example, if the motor control system is controlled by a PLC and the PLC supports a particular interface protocol, then the encoder with the appropriate interface needs to be selected to ensure stable and reliable communication between the encoder and the control system.
4.Consider the mounting method
Shaft encoder: By mounting on the shaft of the motor, it can directly measure the rotation of the motor shaft, which is applicable to various types of motors, but it is necessary to pay attention to the matching of the shaft diameter of the encoder and the motor shaft diameter, as well as the concentricity and perpendicularity of the installation.
Flange encoder: mounted on the end cap of the motor through a flange, it has better stability and vibration resistance, and is suitable for some occasions with higher requirements for installation accuracy.
Magnetic encoder: using the magnetic principle for measurement, does not need to be directly connected with the motor shaft, has the advantages of non-contact measurement, strong anti-interference ability, and so on, is suitable for some of the motors in harsh environments, such as high temperature, humidity, dusty and other occasions.
5.Focus on environmental conditions
Temperature: If the motor works in a high or low temperature environment, you need to choose an encoder that can adapt to the corresponding temperature range. For example, in the high temperature environment of metallurgical industry, you need to choose the encoder that is resistant to high temperature; while in some outdoor equipments in cold areas, you need to choose the encoder that can work properly in low temperature.
Humidity and dust: In humid or dusty environments, encoders with a good level of protection, such as IP67 or higher, should be selected to prevent moisture and dust from entering the encoder's interior and affecting its normal operation.
Vibration and shock: For some motors with large vibration and shock during operation, such as engineering machinery and mining equipment, it is necessary to choose encoders with anti-vibration and shock resistance to ensure the measurement accuracy and reliability of the encoder.
