How to Choose Right Incremental Encoder?

There are many criteria for the selection of FENAC Incremental encoders. In this article, we will give information about how to choose the right encoder.

1-) What will its mechanical properties be like?

·         Diameter of the surface where the encoder will be mounted must be specified.

·         Whether the encoder will be with a coupling or directly attached to the motor shaft must be specified.

·         The diameter of the encoder shaft must be specified.

2-) How many channels do you need?

The encoder can have 6 channels in total, A, B, Z and inverted signals.

If we take a 1024 PPR product as an example;

1: A ; If you want to reach 1024 pulses in just one turn or if you want to measure speed a product with 1 output can be selected.

For example, if you want to divide 360 ​​degrees by 1024 and evaluate each pulse 

2: AB; If you want to determine the direction, A and B signals are used together. There is a 90 degree phase difference between the A and B signals. Direction can be determined from this phase difference. Also known as the "Quadrature encoder interface", the quadrature exchange between two signals helps you increase the resolution by 4 times.

By detecting rising edges and falling edges, the resolution is increased by 4 times, and a resolution of 4096 instead of 1024 can be reached in one turn.

3: ABZ;  the product with 3 outputs has Z, index pulse. The Z pulse is produced 1 per round and used to determine the reference point. 

4: A B; The product with 4 outputs will also have 180 degrees phase difference signals to A and B signals. Although these signals have more wires, they provide signals with higher resistance to noise. This type is generally preferred for long cable products.

6: A B Z; In the 6-output product, the opposite of the Z pulse is also available, and the product with 3 outputs can be preferred for use with longer cables or in noisy environments.,

3-) Input / Output voltage level selection:

Depending on the application, the input supply voltage and the voltage level received at the output may vary. Selection should be made according to the desired voltage levels.

5V: Supply voltage is + 5VDC and output signals will again be at TTL + 5V level.

245V: Supply voltage can be at the desired voltage level between + 5V ~ + 30V. At the encoder output, an output at the level of + 5V will be reached. This output format is called TTL.

30V: Supply voltage can be at the desired voltage level between + 5V ~ + 30V. At the encoder output, an output voltage is reached at the input voltage level. For example, if you supply the encoder with 12V, you will get a 12V level signal at the output

4-) Output voltage level selection:

Fenac encoders are produced with push-pull outputs as standard. Encoders with open collector outputs are also produced upon request.

Therefore, output circuit selection has not been added to the product selection code table.

It contains both NPN and PNP transistors in the push-pull circuit. In addition, this structure includes a pull-up or pull-down resistor. It provides a signal that can be directly used by the user.

There is one NPN transistor in the open collector circuit. For example, if the customer wants to supply the product with 5V but wants to receive a signal at a voltage level of 3V3 from the output, he can connect a pull-up resistor with a 3V3 level to the encoder output and reach a 3V3 signal from the output.

5-) Resolution selection

Fenac encoders can offer a resolution 1 to 100.000 pulses. You can choose the resolution according to the requirements of your application and the reading frequency of your reader.

6-) Electrical connection selection:

Depending on the area of ​​application, the connection cables of connectors of Fenac encoders can be radial side or the back surface.

The cable length should be selected according to the distance between the reader and the encoder in the application area.

In case of change, the product wiring can also be selected with a connector for easy disassembly. The number of connector pins can be selected according to the number of signals on the encoder output.

Click here to watch our video on the subject.