Series of optical incremental linear sensors RG2

Production:

Renishaw (United Kingdom)

RG2 encoder is an open contactless optical linear system with zero friction and no mechanical wear, reliably operating at high speed and with high resolution. A unique optical system that reads the scale in 20 μm increments provides exceptional signal stability under conditions that are unacceptable for most other open optical encoders.

The reading heads perceive an analog signal with a period of 20 μm or have a digital resolution ranging from 5 μm to 5 nm. All linear encoder systems RG2 are equipped with a unique built-in adjustment indicator, the green glow of which means the optimal setting of the system. All reading heads can make zero point and / or limit switch signals. The zero mark signal provides repeatability of the initial or zero position, and the signal of the limit switch serves as an indicator for stopping the movement.

The radiation from the infrared LED is reflected from the inclined strokes of the scale tape and, passing through the transparent phase diffraction grating, returns to the reading head. As a result, sinusoidal interference fringes are formed in the plane of the detector. The optical scheme averages the contribution to the interference pattern from a large number of scale strokes, ignoring signals that do not correspond to the period of the scale. Thus, the output signal is stable even if the scale tape is dirty or slightly damaged.

Often the resultant accuracy of measurements largely depends on the thermal properties of the scale ruler. Since the position of the ends of the scale tape RGS20-S is rigidly fixed, when the temperature changes, its dimensions change with the same coefficient of expansion as the dimensions of the surface on which it is mounted. Therefore, there is no need to introduce an additional coefficient to account the thermal expansion.

The RG2 reading heads are used with a wear-resistant scale tape, which has excellent metrological characteristics, from which you can cut a piece of any desired length. The gold-plated scale tape RGS20-S has a protective lacquer coating and does not need the particularly accurate handling and cleaning that is necessary for most of the conventional scale rulers. The presence of a self-adhesive base and special tools for tape application, corresponding to reading heads of various types, accelerates and simplifies installation. Installation is completed by gluing the zero mark, actuators of limit switches and terminal clamps.