Interferometric laser encoder interfaces and diagnostics

To maximise the capability of your laser encoder system, Renishaw offers diagnostic software and a range of high-speed interfaces to provide high-resolution position feedback in a number of different formats to suit your application.

RPI parallel interfaces

The RPI interface accepts differential analogue 1 Vpp sine/cosine signals, interpolates by 4096 and provides an output in parallel format with up to 36 bits of position data being available. When used in combination with a double-pass plane mirror interferometer system (PMI) (output signal period 158 nm), this results in a Least Significant Bit (LSB) of 38.6 pm (picometres) at velocities of up to 2 m/s.

Active Lissajous correction can be enabled to compensate for DC offset (Automatic Offset Control), AC mismatch (Auto Balance Control) and Phase from the laser encoder to improve the Sub-Divisional Error (SDE) at low velocities.

Renishaw offers the RPI30 and RPI31 parallel interfaces.

RPI30 and RPI31 laser interface for Panasonic controller on white plinths, for laser encoders

Features and benefits

User-configurable resolution as fine as 38.6 pm.
Position is output as a 36 bit parallel word.
Low-latency output.
Automatic SDE correction.
Control and monitoring over SPI and UART.
Analogue quadrature feedthrough.

Difference between RPI30 and RPI31

Specifications	RPI30	RPI31
Parallel bus voltage	3.0 V (3.3 V tolerant)	1.8 V
Max bus output rate	5 MHz	25 MHz
Position filtering	Not included	User-configurable

RLI20-P laser interface - Panasonic

The RLI20-P interface connects a Renishaw laser encoder system with a Panasonic controller. The 1 Vpp analogue quadrature signals from the laser encoder are passed through a high speed interpolator before being output as incremental position in an RS-485 format.

Features and benefits

Panasonic capability - directly compatible with Panasonic controller.
Fast communications - high speed internal position update rate (100 MHz).
High accuracy - low SDE contribution (0.5 nm).

RLI20-P laser interface for Panasonic controller, for laser encoder systems, on a white plinth, with white background

Auxiliary interface for upgrades

An auxiliary interface is required to upgrade an RLE10 or RLE20 legacy laser encoder system to an RLE100 or RLE200 next-generation laser encoder system. It is an adaptor cable that takes three Binder 712 connectors into one LEMO connector. This avoids having to change host machine cabling or control logic.

Features and benefits

Simple upgrade path to the next-generation laser encoder systems.
No need for application redesign.

Auxiliary interface for laser encoder upgrade, on a white plinth

Software

RLE configuration and diagnostic software

RLE CDT is a configuration and diagnostic tool to aid set-up, configuration and live error monitoring of the RLE laser encoder systems. This software is compatible with the RLE100, RLE200 and RLE300 systems.

For download options, please contact your local Renishaw representative for more information.

RPI configuration and diagnostic software

RPI CDT is a configuration and diagnostic tool to aid set-up and live error monitoring of the RPI30 and RPI31 parallel interfaces. This software is compatible with the RLE100, RLE200 and RLE300 systems.

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.

Contact our sales team today

Get in contact with your local office to find out more information and speak to an expert.