 | | SiGNUM™ RELM high accuracy encoder system
 The RELM high accuracy scale offers high speed, non-contact performance, combined with advanced features including dynamic signal processing and the IN-TRAC™ auto-phase optical reference mark. RELM is extremely robust yet offers a level of performance previously available only from more delicate fine pitch encoder systems. With ±1 µm accuracy, low coefficient of thermal expansion and resolution to 5 nm, RELM satisfies the most demanding precision motion requirements.
The system comprises:
- RELM 20 µm pitch Invar spar
- SiGNUM™ SR readhead
- SiGNUM™ Si interface
RELM 20 µm pitch Invar scale
 20 µm pitch RELM scale is manufactured from Invar, a low expansion nickel/iron alloy. The robustness of Invar permits a much smaller cross section than glass scale, yet allows easier handling and installation, without risk of breakage.
- Available in defined lengths with custom lengths available on request
- Accuracy is individually certified to ±1 µm, calibrated against International Standards
- Low coefficient of thermal expansion: Invar, ~0.6 µm/m/°C (0°C to 30°C)
- IN-TRAC™ auto-phase optical reference mark, bi-directionally repeatable even at maximum system speed (12.5 m/s)
- Mid-point (RELM) and end (RELE) reference mark positions available as standard
- Dual optical limits provide on-scale end of travel indication
- Easy to install, direct to the substrate, using datum clamp and clips or adhesive backing tape
SR readhead and Si interface features and benefits  Cyclic error of ±30 nm, offering 'fine pitch' encoder performance- Capable of operation up to 12.5 m/s and 85 °C
- Excellent signal stability in conditions unsuitable for most open optical encoders
- Si interface offers industry standard analogue and digital outputs
- User selectable gain control (AGC) maintains 1 Vpp analogue signal amplitude
- Integral LEDs on readhead and interface for optimum set-up and system diagnosis
- High flex UL approved cable – up to 10 m between readhead and interface
- Optional IP68 in-line connector available
Compare the SR with alternative optical linear readheads.
SiGNUM™ software
 SiGNUM™ software is PC based and provides comprehensive calibration, set-up optimisation and real-time diagnostics to simplify installation and system maintenance. The Si interface is connected to the PC via a mini USB connector.
- "Real time", remote monitoring of signal level and system performance, including signal strength meter, Lissajous plot and IRED feedback meter (AGC drive), to assist with system optimisation
- Pitch adjustment indicator enables fine adjustment of the readhead pitch
- Quick and simple remote calibration of the reference mark and incremental signals
- System alerts warn the user of conditions that are less than optimum (warning function) and of any errors that occur (alarm function)
- Technical "info" guide provides contextual help and a detailed explanation of system functions and fault-finding
- System configuration page displays Si interface configuration detailing resolution, clock frequency, etc.
- Multilingual user interface allows the user to select from English, German, Italian and Japanese
Download SiGNUM software now.
Technical specifications
| Readhead dimensions |
14.8 mm x 36.0 mm x 16.5 mm (H x L x W) |
| Outputs (resolution) |
RS422: 5 µm, 1 µm, 0.5 µm, 0.2 µm, 0.1 µm, 50 nm, 20 nm, 10 nm, 5nm.
Analogue: 1Vpp |
| Interpolation |
Si interface (x4 to x4000) |
| Reference mark |
IN-TRAC™ auto-phase optical |
| Limit switches |
Customer positioned optical dual limits |
| Maximum speed |
12.5 m/s |
| Ride height tolerance |
0.8 ±0.08 mm |
| Scale types |
20 µm RELM Invar spar |
| Vacuum compatible |
No |
Additional resources
Accessories and external interpolation options
For further information and product options, visit the encoder product configurator.
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