RLU laser units for interferometric displacement measurement
Renishaw RLU laser units provide a reliable fibre-delivered laser source with superior frequency stability for high-performance interferometric position measurement.
High performance for motion control applications
The laser units RLU100, RLU200 and RLU300 are part of the RLE range of high-accuracy interferometric laser encoder products.
Using a frequency-stabilised Helium-Neon laser source, these laser units include flexible diagnostic and interface capabilities, along with precision electronic and opto-mechanical assemblies.
They are compatible with the high-performance DI differential interferometer detector heads and the versatile PMI plane mirror interferometer detector heads.
They provide accurate position feedback for a wide range of high-precision motion control systems.
RLU100 laser unit
The RLU100 laser unit, included in the RLE100 laser encoder system, is the direct successor to the RLU10 laser unit. It offers enhanced measurement performance (laser frequency stability) for in-air applications. It is well suited to precision, high-throughput applications in atmospheric conditions.
RLU200 laser unit
The RLU200 system, part of the RLE200 laser encoder system, is the direct successor to the RLU20 laser unit. It delivers enhanced measurement performance for higher-performance applications, and particularly those in vacuum environments. It incorporates automatic SDE correction in the form of Automatic Balance Control (ABC) and Automatic Offset Control (AOC). These processes optimise the analogue position signal which enables large interpolation factors to be used to obtain stage position with high resolution across a range of signal levels.
RLU300 laser unit
The RLU300 laser unit, the core of the RLE300 laser encoder system, offers the same benefits as the RLU100 and RLU200 laser units but is the most stable laser encoder Renishaw has ever produced. With next-level performance, it meets the requirements of the most demanding motion control applications. The combination of exceptional laser frequency stability with automatic SDE correction delivers superior position measurement with high accuracy and low positional noise.
Technical specifications
| Specifications | RLU100 | RLU200 | RLU300 |
| Laser source | HeNe Class II < 500 µW (CW) / axis | Same as RLU100 | Same as RLU100 |
| Analogue output | 1 Vpp sine/cosine signals Signal period = λ/4 (158 nm nominal) | Same as RLU100 | Same as RLU100 |
| Digital output | Dual RS-422 differential digital quadrature Resolution = 0.3 nm to 20 µm | Same as RLU100 | Same as RLU100 |
| Laser frequency stability (3 seconds) | N/A | N/A | < 0.1 ppb |
| Laser frequency stability (1 minute) | < 10 ppb | < 1 ppb | < 0.5 ppb |
| Laser frequency stability (1 hour) | < 20 ppb | < 2 ppb | < 1.0 ppb |
| Laser frequency stability (8 hours) | < 25 ppb | < 10 ppb | < 3.0 ppb |
Downloads: datasheets and technical documents
Further information about the technical specifications of the Renishaw laser encoder products, such as datasheets and installation guides, are available from our technical downloads section.
Discover our range of interferometric laser encoders designed to meet your high-accuracy motion control needs.