Precision Magnetic Linear Scales
OTV manufactures high-performance magnetic linear scales and linear encoder tapes for absolute and incremental position feedback. Dual-track Nonius encoding with pole pitches from 1.0 mm to 5.0 mm. Custom linear encoder scales for robotics, CNC, semiconductor, and industrial automation.
- Dual-track absolute magnetic linear scale — instant position on startup, no homing
- Custom linear encoder tape: pole pitch, width, thickness, and length to your spec
- Compatible with AMR, TMR, and Hall-effect readheads
- Standard linear encoder scales from 100 mm to 15 m; custom lengths available
- Sample lead time: 3 weeks | Mass production: 4 weeks
What Is a Magnetic Linear Scale?
A magnetic linear scale (also called a linear encoder tape or linear encoder scale) is a precision-magnetized flexible strip that, together with a magnetic readhead, forms a non-contact absolute or incremental linear position feedback system.
How a Linear Encoder Scale Works
A linear encoder scale carries one or two magnetized tracks of alternating N/S poles. For absolute encoding, OTV uses a dual-track (Nonius/Vernier) architecture:
The Linear Nonius (Vernier) Principle — Illustrated
The diagram below demonstrates how the phase difference between two tracks with different pole counts uniquely encodes absolute position. A single iC-MU encoder IC reads both tracks simultaneously and computes the phase offset to determine the exact location within one measurement cycle.
Figure: The phase difference Δφ between the Master (32 PP) and Nonius (31 PP) signals varies from 0° to nearly 360° across the 96 mm measurement cycle. Each Δφ value corresponds to exactly one absolute position.
The complete system consists of two primary components: the magnetic linear scale tape (a stainless steel carrier coated with bonded ferrite rubber, magnetized with the dual-track pattern) and the readhead (containing the magnetic sensor IC and signal processing electronics). As the readhead moves along the scale, it detects field variations, computes absolute position in real time, and outputs via BiSS-C, SSI, SPI, or RS-485.
Absolute magnetic linear encoder scale system — dual-track Nonius encoding provides instant absolute position on startup
Custom magnetic linear encoder tape with precision-magnetized pole pattern
Readhead Technologies & Encoder IC Matching
OTV linear encoder tapes are engineered to work with all major magnetic sensing technologies and leading encoder IC families. We match pole pitch, track configuration, and magnetization pattern to your chosen chip.
Sensor Technologies Compatible with OTV Linear Encoder Scales
AMR (Anisotropic Magneto-Resistive)
Operates in saturation mode (>300 Gauss). Responds only to field direction — not amplitude — providing inherent gap tolerance. Excellent signal-to-noise ratio for high-precision magnetic linear scales.
TMR (Tunnel Magneto-Resistive)
Next-generation technology with higher signal output and up to 50% lower power consumption vs. Hall sensors. Superior temperature stability. Ideal for battery-powered linear encoder tape applications.
Hall Effect
Proven, cost-effective technology for general industrial use. Suitable for standard linear encoder scales in CNC, packaging, and factory automation where integration simplicity is key.
IC-Haus iC-MU Series — Dual-Track & Triple-Track Magnetic Scale Requirements
The iC-MU family from IC-Haus is the leading encoder IC platform for off-axis absolute position sensing. OTV linear encoder scales are precisely matched to each chip variant's pole width, track count, and encoding requirements.
| Chip Series | Pole Width (Master) | Track Configuration | Resolution (Bits) | Scale Material | Key Notes |
|---|---|---|---|---|---|
| iC-MU | 1.28 mm | 2-Track (Master + Nonius) | 18–20 bit | Magnetic Tape / Disc | Compact form factor; ideal for space-constrained linear encoder tapes |
| iC-MU150 | 1.50 mm | 2-Track (Master + Nonius) | 18–20 bit | Magnetic Tape (e.g., MU7S 25-32N standard reference) | Optimized Hall sensor spacing for 1.50 mm pole width; supports linear absolute scales |
| iC-MU200 | 2.00 mm | 2-Track (Master + Nonius) | 18–20 bit | Magnetic Tape / Disc | Larger mechanical envelope; higher pole count capacity for longer linear encoder scales |
2-Track vs. 3-Track Nonius Systems
2-Track (Dual-Track) Nonius
The standard absolute encoding scheme. One Master track and one Nonius track (with exactly 1 fewer pole pair over the same measuring length). The phase difference between the two tracks uniquely identifies the absolute position within one measurement cycle. A single iC-MU chip handles both tracks — no chip cascading required.
Standard 2-Track Configurations
OTV standard magnetic linear scales are pre-engineered for the three iC-MU chip variants:
| Chip | Master PW | Max MPC | Max Cycle Length | Resolution |
|---|---|---|---|---|
| iC-MU | 1.28 mm | 64 | 163.8 mm | 18 bit |
| iC-MU150 | 1.50 mm | 64 | 192.0 mm | 18–20 bit |
| iC-MU200 | 2.00 mm | 64 | 256.0 mm | 18–20 bit |
Key Specs (2-Track Standard):
- Pole Pairs Ratio: Master : Nonius = N : (N-1) — fixed 1-pair difference across all MPC values
- Measurement Cycle: N × 2 × Pole Width (e.g., 32 PP × 2 × 1.50 mm = 96 mm)
- Single Chip: One iC-MU series IC — simpler integration, lower cost than 3-track
- Phase Tolerance: ±4.92° (32 PP) to ±2.46° (64 PP) — more forgiving than 3-track systems
Dual-track Nonius magnetic linear scale — Master + Nonius tracks
3-Track (Triple-Track) Nonius — Extended Absolute Range
A 3-track system adds a Segment track to the standard Master + Nonius architecture. This enables significantly longer absolute measurement ranges by using two encoder ICs cascaded together. The Segment track provides a coarse absolute position, while Master + Nonius deliver fine resolution within each segment.
Why 3 Tracks Are Needed
A single iC-MU chip supports a maximum of 64 Master pole pairs (MPC) in hardware. For applications requiring longer measurement lengths without sacrificing resolution, the MPC must exceed 64. This is achieved by cascading two encoder ICs and adding a third (Segment) track with a different pole pair count. The ratio is fixed:
Master : Nonius : Segment = 256 : 255 : 240
Example: MPC = 256 with iC-MU150 (1.50 mm pole width)
| Track | Pole Pairs | Pole Width | Calculation |
|---|---|---|---|
| Master | 256 | 1.500 mm | Fixed specification (chip sensor pitch) |
| Nonius | 255 (Nm - 1) | 1.506 mm | 1.50 × 256/255 |
| Segment | 240 | 1.600 mm | 1.50 × 256/240 |
Key Performance Data (MPC=256, iC-MU150):
- Absolute Measuring Length: 256 × 3.00 mm = 768 mm (iC-MU200: 256 × 4.00 mm = 1024 mm)
- Absolute Resolution: Up to 22 bits
- Max Phase Deviation Tolerance: ±9.84° (electrical) — much tighter than lower MPC systems
- Hardware: Requires two iC-MU chips cascaded (e.g., iC-MU150 or iC-MU200)
- Track Spacing: Adjacent track center distance typically 3.6 mm to match chip sensor array
Available on request for custom magnetic linear scale projects. Higher MPC values (1024, 4096) are available for even longer measurement ranges — contact OTV for feasibility analysis.
Triple-track Nonius magnetic linear scale — Master + Nonius + Segment for extended absolute measurement range
OTV Magnetic Linear Scale & Encoder Tape — Standard & Custom
OTV offers both standard magnetic linear scales for common encoder IC platforms and fully custom linear encoder tapes tailored to your specific mechanical and electrical requirements.
Standard Magnetic Linear Scales
Absolute Magnetic Linear Scale (Dual-Track Nonius)
Standard dual-track magnetic linear scale for absolute position feedback. Nonius encoding provides instant absolute position on startup.
Incremental Linear Encoder Tape (Single-Track)
Single-track linear encoder tape for incremental applications. With optional stainless steel carrier backing for mechanical stability.
Full Specifications — Standard & Custom Range
| Parameter | Standard Products | Custom Range |
|---|---|---|
| Pole Pitch | 1.28 mm / 1.50 mm / 2.00 mm | 1.0 mm – 5.0 mm, any custom pitch |
| Measuring Length | 100 mm – 5,000 mm | Custom lengths beyond 5 m |
| Track Configuration | Single-track (incremental) / Dual-track (absolute Nonius) | Triple-track Nonius for extended absolute range |
| Scale Width | 8 mm / 10 mm | Custom width |
| Scale Thickness | 1.0 mm | Custom thickness per envelope |
| Magnetic Material | Bonded Ferrite Rubber (NBR matrix) | NdFeB or high-temp compounds |
| Carrier Material | Stainless Steel (optional) | Custom backing / adhesive options |
| Resolution (with readhead) | 0.5 µm / 1.0 µm (selectable) | — |
| Repeatability | ±1 µm | — |
| Output Protocol | BiSS-C / SSI / SPI / RS-485 | Consult for other protocols |
| Environmental Sealing | IP67 | — |
| Operating Temperature | -20°C to +85°C | High-temp grades available |
| Compatible Encoder ICs | iC-MU / iC-MU150 / iC-MU200 | Custom matching to any Hall/AMR/TMR IC |
| Sample Lead Time | 4 weeks | — |
| Mass Production Lead Time | 2 weeks | — |
Custom Linear Encoder Scale Solutions
Custom Dimensions
Any measuring length, width, and thickness. From ultra-compact linear encoder tapes (1.0 mm thin) to large-format magnetic linear scales for long-travel CNC machines.
Custom Pole Pitch & Tracks
Single, dual, or triple-track layouts. Custom pole counts per track. Optimized pole width to match any encoder IC — iC-MU series or others.
Custom Materials & Mounting
Choice of ferrite or NdFeB compounds, with or without stainless steel carrier. Adhesive backing, bolt-down, or press-fit linear encoder scale mounting.
Requirements
Define length, pitch, accuracy, environment
Design
Engineer scale pattern & materials
Prototype
Samples in ~4 weeks for validation
Production
Full-scale with 100% inspection
How a Magnetic Linear Encoder Scale System Is Built
1. Magnetic Linear Scale (the Tape)
A stainless steel carrier strip coated with bonded ferrite rubber, magnetized with precision pole patterns. For absolute encoding, the linear encoder scale carries two tracks — one incremental Master track and one absolute Nonius track with one fewer pole pair across the total measuring length.
2. Readhead (the Sensor)
Contains the magnetic sensor IC and signal processing electronics. As it moves along the linear encoder tape, the IC detects magnetic field variations from both tracks, calculates the phase difference via the Nonius principle, and outputs absolute position in real time.
Where Magnetic Linear Encoder Scales Excel
Robotics & Automation
Collaborative robots, linear actuators, positioning stages. Linear encoder scales provide absolute position feedback for safe, coordinated multi-axis motion.
CNC & Machine Tools
CNC machining centers, grinding, EDM. Magnetic linear scales resist coolant, chips, and vibration — reliable where optical scales fail.
Medical & Laboratory
Surgical robots, CT/MRI positioning, diagnostic imaging. Compact linear encoder tapes for precision medical motion control.
Semiconductor
Wafer handlers, inspection stages, lithography. Ultra-high-resolution magnetic linear scales for cleanroom positioning.
Pick-and-Place & Packaging
High-speed pick-and-place, automated packaging. Linear encoder tapes deliver the speed and repeatability for 24/7 production.
Linear Motor Feedback
Direct-drive linear motors. Encoder scales provide high-resolution position data for commutation and closed-loop control.
Common Questions About Magnetic Linear Scales & Encoder Tapes
What is the difference between a magnetic linear scale and an optical linear scale?
Magnetic linear scales are inherently more robust than optical scales. They are immune to dust, oil, moisture, and condensation — there is no optical path to obstruct. They also tolerate larger installation tolerances and are less sensitive to vibration and shock, making them ideal for harsh industrial environments.
Do your linear encoder tapes support absolute position output?
Yes. Our absolute linear encoder scales use a dual-track (Nonius) magnetic pattern and output protocols such as BiSS-C. They provide a unique position value immediately upon startup — no reference run or homing sequence required. Incremental encoder tapes are also available.
Can I order just the magnetic linear scale without a readhead?
Yes. OTV supplies standalone custom magnetic linear scales and encoder tapes separately. This is ideal for system integrators who have already selected an encoder IC or readhead and need a tailored magnetic target.
What is the maximum length of a linear encoder tape?
Standard linear encoder scales go up to 5 meters. For longer travel distances, custom scales can be manufactured — contact us with your specific requirements.
Which encoder ICs are your linear encoder scales compatible with?
Our standard magnetic linear scales are precisely matched to the IC-Haus iC-MU family (iC-MU, iC-MU150, iC-MU200) with correct pole widths (1.28 mm, 1.50 mm, 2.00 mm). We can also customize linear encoder tapes for other Hall, AMR, or TMR encoder chips — contact us with your IC specifications.
Can I get a custom linear encoder tape sample before ordering in volume?
Yes. Custom magnetic linear scale samples are available for validation at a nominal fee. Lead time is generally 4 weeks after design confirmation. We're flexible on MOQ for prototype and trial orders.
Ready to Spec Your Magnetic Linear Scale or Encoder Tape?
Tell us your measuring length, pole pitch, accuracy requirements, and environmental conditions. Our engineering team will recommend the optimal magnetic linear scale or linear encoder tape for your application — and deliver a custom sample in as fast as 4 weeks.