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RCU10 real-time quadrature compensator

Compensation systems for real-time quadrature positional feedback.

RCU10 compensator unit and sensors

When any laser interferometer system is used in a non-vacuum environment, some form of environmental compensation is required to maintain accuracy under varying environmental conditions. The principle of interferometry is dependent on the wavelength of the laser light, a figure which fractionally varies depending on the refractive index of the air through which it travels.

Environmental changes of ±1 °C in air temperature, ±3.3 mbar in air pressure, or 50% variance in relative humidity would generate a 1 ppm variance in laser wavelength and resulting measurements.

The input and output parameters for an RCU10 unit are configured with the Renishaw Configuration Software (RCU-CS).  This can be downloaded from the link at the bottom of this page.

Features and benefits

  • Accuracy - refractive index compensation for laser encoders using air pressure and temperature sensors, improves accuracy to within ±1 ppm.
  • Yield enhancement - thermal expansion compensation of workpiece and machine structures, using material temperature sensors, dramatically improves process repeatability.
  • Flexibility - RCU10 can also be used for compensation with many other laser and scale encoders that provide digital quadrature feedback signals.

Configuring RCU10 systems

The following options should be considered when defining your RCU10 system:

  • RCU10 compensation units are available with or without an integral pressure sensor (RCU10-PX-XX and RCU10-XX-XX respectively)
  • For multi-axis systems, up to six RCU10s can be linked via a high-speed serial communications link. If used as part of a multi-axis system, only one RCU10-PX-XX is required.
  • Air temperature sensors
  • Material temperature sensors

To determine the part number of the compensation system required for your individual application, simply enter your requirements into the grey cells of the RCU10 part number generator.  It will automatically calculate the necessary system part number which can then be used to request a quotation or place an order.


FeaturesRefractive index compensation
Material expansion compensation
Accuracy ±1 ppm*
Data format Digital - RS422 quadrature
Analogue - 1 Vpp sine / cosine
Resolution Digital - variable to 10 nm
Analogue - variable to 20 µm
Velocity Up to 5 m/s

* plus the greater of 3 input counts and 1 output count for digital outputs and a further velocity dependant error for some analogue outputs.

Optional extras

A number of optional extras are also available for use with the RCU10 real-time quadrature compensation unit.
A-8014-0670Serial / USB adaptor
RCU10-DB-XXSensor distribution box
RCU10-AC-X5Armoured sensor cable (5 m length)
RCU10-AT-XX Air temperature transmitter
RCU10-MT-XX Material temperature transmitter

Software download

  • Software download: RCU CS v2.0.5

    RCU CS is the RCU10 configuration software. It allows all the parameters and operational modes to be configured before the RCU10 may be used. It also provides an operational display to monitor the compensation process, environment and error status.

Product information