ISO 9001:2015
Modern means of measuring equipment

Optical incremental linear encoder SiGNUM with a high-precision RELM scale from Invar

Renishaw plc (Graet Britain)

Encoder SiGNUM with a high-precision RELM scale from Invar
Encoder SiGNUM with a high-precision RELM scale from Invar

The new high-precision RELM line provides high speed and non-contact readout in combination with new solutions including dynamic signal processing and IN-TRAC ™ - optical zero mark with automatic synchronization. SiGNUM encoder system with the RELM line is exceptionally resistant to external influences, while providing the performance inherent only to encoders with a much smaller scale step. With an accuracy of ± 1 μm at lengths up to 1.13 m, a low coefficient of thermal expansion and resolution up to 5 nm, the RELM line meets the highest requirements for precision motion measurement systems.

The system includes the following components:
- Invisible ruler RELM with a step of 20 microns,
- SiGNUM ™ SR reading head,
- Si-interface SiGNUM ™.

Features and benefits of the SR and Si interface reader

— Periodic error: ± 30 nm, which ensures the accuracy of operation inherent in encoders with a smaller pitch
- Ability to work at speeds up to 12.5 m/s and temperatures up to 85 0 C.
- Extremely high signal stability under conditions not acceptable for most open optical encoders.
- Si - interface provides standard analog and digital output signals.
-The user-selectable automatic gain control (AGC) mode allows to maintain a constant analog signal amplitude of 1 Vpp.
- Easy setup and diagnostics of the system thanks to LED indicators on the reading head and interface.
- The flexible cable between the reading head and the UL-compliant interface is up to 10 m long.

Optional line-connected connector with protection class IP68.

Invar RELM with 20 μm pitch

RELM ruler in 20 μm increments is made of Invar, a nickel-iron alloy having a low expansion coefficient. Due to the high strength of Invar from it, it is possible to produce rulers with a much smaller cross section than glass. At the same time it is easier to handle Invar rulers during transportation and installation, without risking to break them.
- A number of standard rulers are available up to 1130 mm in length, custom-made lengths are available on request.
- Accuracy up to ± 1 μm, certified for each line separately with verification in accordance with international standards.
- Low coefficient of thermal expansion: Invar, ≈ 0.6 μm/m/ 0 C-0 0 C ).
- Optical zero mark IN-TRAC ™ with automatic synchronization provides two-way repeatability of arrival to the zero point at speeds of up to 12.5 m / s.
- The mean (RELM) and the extreme (RELE) positions of the zero mark are provided as standard.
- Pair limit switches installed directly on the line provide an automatic feed of the signal that initiates the stop of the moved assembly.
- Easily installed, directly on the substrate, using a base bracket and clamps or a self-adhesive base.

SiGNUM ™ Software

SiGNUM ™ package is installed on the computer and allows for comprehensive calibration, optimization and real-time diagnostics, which simplifies the installation and maintenance of the system. The Si-interface is connected to the computer via a connector with a mini-USB connector.
- Work in "real-time" mode, remote monitoring of signal level and system characteristics, including infrared signal level indicator, Lissajous figures output, feedback indicator (automatic gain control system operation) - all these tools allow optimize the operation of the entire system.

The head angular position indicator allows fine adjustment of the pitch angle of the reading head.
- Fast and easy remote calibration of zero mark signals and incremental encoder signals.
- Issue alerts that indicate that the operating conditions are below optimal (warning), or that there is a malfunction (alarms).
- The Technical Reference Guide provides context-sensitive help with a detailed description of the system functions and troubleshooting methods.
- The system configuration page displays data related to the configuration of the Si-interface, in particular, resolution, clock frequency, etc.
- The user can choose one of the following interface languages: English, German, Italian and Japanese.


Built-in LED
head position indicator
Measuring range, m: — from 0,07 to 1,12
Length of the optical scale RELM, m: —from 0,08 to 1,13
Resolution of digital output signal RS422, nm: 5, 10, 20, 50, 100, 200, 500, 1000, 5000
Resolution of analog output signal: — 1 Vpp
Step of the scale, mkm: 20
Max speed, m/s: 12,5
Clearance between reading head
and optical scale, mm:
0,8 ± 0,15
Accuracy of the system at a length of up to 1.13 m at 20° C, μm:: ± 1
Scale option: — mechanical clamps and base clamp
- self-adhesive base
Coefficient of thermal expansion, μm/m/°С: — ≈ 0,6 (under temperature from 0 °C to 30 °C)
— less than 1,4 (under temperature from 30 °C to 100 °C)
Supply voltage, V: 5 ± 10 %
Current consumption (without load), mA: — 250 (in typical conditions)
Material of the optical scale RELM: — highly stabilized, low-expansion iron-nickel alloy (ZeroMet. - Invar)
Cable: — flexible, with double shielding, outer diameter 4.7± 0,1 mm, cable service life for bending more than 20 x 10 6 cycles with a bend radius of 20 mm, corresponds to UL standard
Length of the cable, m: 0.5, 1, 1.5, 3, 5, 10 (14-pin connector, for connection directly to the Si-interface)
Dimensions of the reading head SR (height × length × width), mm: 14,8 × 36,0 × 16,5
Mass, g: reading head SR-15
- Si-interface - 205
Mass, g/m: optical scale RELM - 180,7
- cable - 35
Reference mark (zero): optical, IN-TRAC, with automatic zero-signal synchronization
Limit switches: paired, optical
Temperature, °С: — process reading head SR - 0 to + 85 V - process - Si-interface - 0 to + 70 V - storage - system SiGNUM - from - 20 to + 70
Degree of protection: optional in-line connector - IP68
- readout head SR - IP64
- Si interface - IP30
(without compensation, with temperature + 40 °C), %:
Process acceleration, m/s 2: 500
Impact (in non-operating state,
6 ms, half-sinusoidal impulse), m/s 2:
Vibration (in operation mode, at, at 55-2000 Hz), m/s2: 100

Additional information


Description and technical specifications