Encoder FAQ's

Which encoder is best for which application?

This decision is usually based on the resolution and accuracy needed as well as the most suitable functional principle (optical/magnetic) and operating temperature range of the encoder types available for the desired motor series.

For which encoder types is a second shaft end available?

If a second shaft end is needed, brushless DC-Servomotors generally use analogue Hall sensors as angle sensors. If needed, encoders are installed downstream of the other add-on components, such as brakes for example.

What line lengths are possible with/without Line Driver (RS422)?

Without Line Driver, line lengths of up to 1-2 m are possible with incremental encoders. In individual cases, the function may depend on other parameters, such as the motor PWM and cable installation.
With Line Driver and twisted-pair cables, line lengths of up to several tens of meters are conceivable. What matters in this case is the differential evaluation at the end of the line or controller. In addition to this, a connection resistance at the line end may be useful for longer line lengths in order to suppress reflections.

Which encoder types are available from FAULHABER?

FAULHABER offers encoders based on the optical and magnetic functional principles.

Which encoder interfaces are available?

FAULHABER offers encoders with quadrature interface, absolute interface (BiSS-C) as well as analogue and digital Hall signals. Other interfaces are also possible on customer request.

Does FAULHABER use standardised encoder interfaces?

Yes, standardised interfaces such as quadrature interfaces acc. to RS422, absolute interfaces acc. to BiSS-C as well as digital Hall sensors are used.

What is the difference between an encoders resolution and accuracy?

The resolution of an incremental encoder (4* lines per revolution) is the smallest measurable angle. FAULHABER encoders have an angular resolution of up to 0.009°.
The accuracy is generally a multiple of the resolution. FAULHABER encoders achieve an accuracy of up to 0.1°. The accuracy describes the maximum deviation of the actual position from the set value. For newer products such as the IER3 and IE3, this information is provided in the data sheets.
You can find more detailed information on the position accuracy and repeatability in the technical information in chapter Encoders.

Do FAULHABER encoders require additional protective measures against EMC?

Additional protective measures are already incorporated in some encoders, such as the IE3 and IER3. Generally speaking, the specification limits (e.g. supply voltage range) indicated in the data sheets must be heeded. In individual cases, it may be necessary to take additional measures for the customer’s application. What is critical in this respect are primarily voltage peaks on the voltage supply and signal lines, which can lead to a latch-up effect in the sensors and cause their destruction.