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Functional Safety

Certain machinery safety functions, such as Safely Limited Speed (SLS), require the encoder feedback to be functionally safe. Utilising an encoder system that is already rated for use in safety-related applications can make machine certification significantly easier. Adopting these advanced machine safety functions allows machine builders to make safer machines, capable of higher functionality that reduce set-up times and machine downtime.


For safety critical applications, Renishaw offers a range of functionally safe position encoder solutions certified to the following international safety standards:

ISO 13849 Category 3 PLd
IEC 61508 SIL2
IEC 61800-5-2 SIL2

Renishaw also provides reliability data for its Functional Safety rated readheads.

The TONiC FS series offers all the benefits of the established TONiC™ linear and angle encoder systems. For exceptional metrology performance and ultimate reliability, TONiC readheads incorporate Renishaw's market proven third generation filtering optics; these are further enhanced by dynamic signal processing including Auto Gain Control and Auto Offset Control. The result is low Sub-Divisional Error (SDE) and even lower noise (jitter) giving smoother velocity control for improved scanning performance and increased positional stability.

The RESOLUTE FS series offers all the benefits of the established RESOLUTE™ linear and angle encoder systems. The RESOLUTE encoder uses a single optical absolute track with a nominal pitch of 30 μm, combined with sophisticated optics. This ensures wide set-up tolerances, very low Sub-Divisional Error of ±40 nm and ultra-low noise (jitter) of less than 10 nm RMS, resulting in better velocity control performance and excellent positional stability. Reliability is assured by RESOLUTE's high dirt immunity, built in separate position checking algorithm and IP64 sealed readhead with wipe clean recovery.

The FORTiS FS series offers all the benefits of the FORTiS linear enclosed encoder system. FORTiS encoders offer an exceptionally robust design for use in harsh industrial environments where high precision feedback and metrology are required. A sealed optoelectronic readhead converts motion relative to a finely graduated stainless steel scale into position data. FORTiS encoders are based on market-proven absolute measurement technology and feature a non-contact design which provides superior sealing, exceptional vibration resistance and easy installation with a patented set-up LED.


Reliability data for Renishaw Functional Safety encoders

Renishaw provides reliability data for its Functional Safety rated TONiC™ FS, RESOLUTE™ FS and FORTiS™ FS readheads as a SISTEMA library, in order to assist customers with their Performance Level (PL) calculation. This enables system designers to copy that data from a library into a SISTEMA project, quickly and without any errors.

SISTEMA: Safety Integrity Software Tool for the Evaluation of Machine Applications

SISTEMA is a software tool to calculate Performance level (PL), for the implementation of EN ISO 13849-1. Provided by IFA, SISTEMA is a free software and is widely recognised within the industry.

System designers and safety specialists can also download the SISTEMA software free of charge, via this link.