RSF Elektronik: MS 3x Series

(Open Linear Encoders with non-contact singlefield scanning)

The trend today in motion control applications is for exposed Linear Encoder systems. This is driven by steadily increasing demands for:

Only exposed, non-contact encoders fulfill all these requirements.

It is important for high resolution applications to minimize interpolation errors. Historically, the small grating periods used had the disadvantages of smaller mounting gaps and very tight overall mounting tolerances. The MS 3x encoders´ 20 μm grating period minimizes interpolation errors but can be mounted with a large mounting gap and liberal mounting tolerances.

A drawback of many exposed Linear Encoders is their sensitivity to dirt and contamination on the scale. The MS 3x encoders´ unique optical design minimizes the effect of dirt and contamination normally associated with the exposed Linear Encoders.

The MS 3x utilizes a unique scanning principle which allows high traversing speeds (up to 7 m/s), large mounting tolerances, and contamination on the scale.

Reference marks, accurate and repeatable from both traversing directions, are standard.

A wide range of interpolation electronics, integrated into the encoder head, enable resolutions from 5 μm to 50 nm. Square-wave signals, single ended, or via Line Driver RS 422, are provided at the output of the encoder head.

Units with sinusoidal output, 1 Vpp, are also available.

Two end of travel optical switch signals are available directly out of the reading head. The end of travel signal locations can be easily set by the user.

Due to recent advancements in technology, all of these benefits are now available in a small package design.

Scanning Principle

The model MS 3x incremental Linear Encoder works with the imaging, photoelectric measuring principle and a singlefield reflective scanning method.

The regulated light of an infrared LED is collimated by a condenser lens and passes through the grid of the reticle. After being reflected from the scale the infrared LED generates a periodic intensity distribution on the structured sensor.

The sensor generates high quality sinusoidal signals which are highly insensitive to possible contaminations.

The regulation of the LED ensures a constant light output, guaranteeing stability in the case of temperature fluctuations as well as with long-run operation.