If I am using packaging machines or cutting metal to a certain length or have an automation project, how do I know if the package was packed correctly, the length of the metal is right, and the angle and position of the automation equipment are accurate? In this situation, we use a motion-sensing device called an encoder. 

Another example is if there is an error in an industrial robot, it requires calibration. The calibration process includes measurement and identification of actual value. This task can be performed by an encoder. 

Let HONTKO tell you details about the encoder and its two most widely used types: incremental type and absolute type.

What is an Encoder?

Encoders switch mechanical motion into electrical signals and give the important value like position, speed, count, distance, and direction to enhance and correct system performance. The control device such as a PLC system will use this signal to implement a particular command. 

For instance, when cutting material to a certain length, an encoder sends signals to the control device about how much material has been fed, so the control device knows when to cut.

In a bottle packaging or labeling procedure, PLC uses encoder signals to manage velocity and timing. Besides, In the filling procedure, their signal lets the bottle-filling machines know the position of the containers.

Why Encoder is Important?

Given these points above, it plays an important role in almost all industrial uses: industrial automation equipment, medical equipment, energy, etc. 

Mechanical systems require encoders as feedback systems to operate accurately.

Application of encoders:

• Industrial robot / robotic arms

• Medical Equipment

• Energy

• Aerospace

• Automation 

• Construction

• CNC Machining

• Electronics Industry

The Difference Between Incremental and Absolute Encoders

There are various encoders for different uses. Separated by sensing techniques, encoders can be classified into linear encoders and rotary encoders. If separated by electromechanical technologies, they can be classified into magnetic, optical, inductive, and capacitive types.

There are 2 different encoder measurement types: Absolute and Incremental. 

An absolute encoder gives absolute position information to the control device, while an incremental encoder can obtain speed and direction information. Their operations are different, but both can apply linear and angular displacements.

Incremental type

Incremental encoders’ output is a pulse, which was considered as an incremental signal.

If we need velocity and direction data of the appliance, we use incremental encoders. Incremental encoders always count from zero when it is switched on or reset. It creates an output signal when the shaft moves. It measures the position change, not the absolute position.

Pros:

Easy to produce

Cheaper than absolute type

Detect speed, direction

Cons:

Need to locate a reference point

Position references will be lost if power is turned off

Absolute type

Absolute encoder is an angle transducer whose signal signifies the present shaft position. Absolute encoders directly provide the digital output that indicates the absolute displacement. The existing position is determined instantly when the system is switched on.

Pros:

Can implement absolute angle readings

No reference point required

The result remains even if there is no electric supply

Cons:

Complicated and expensive to produce

Cost higher than incremental encoders

Conclusion

Taken together, incremental and absolute encoders both are the equipment of controlling machines for industrial controlling and other purposes. Both of them have advantages and disadvantages, HONTKO suggests you choose by your purpose of detection.

To illustrate, if you need to know the exact index of your automation equipment, absolute encoders will be the best choice. While incremental encoders will be suitable if you need to obtain speed and direction information. 

With 30 years of experience, HONTKO is a leading optical encoder manufacturer in Taiwan. Want to know more about encoders? Please do not hesitate to contact us if you require a quotation or technical support!