Absolute Magnetic Linear Encoders
Compare complete absolute magnetic readhead-and-scale systems by travel, resolution, mounting gap and controller interface.
- Resolution down to 0.1 µm with AL200
- Travel up to 82 m with AMG5000
- SSI and BiSS-C options, depending on model
Specify the complete linear feedback system
Choose a matched readhead and magnetic scale, then check the electrical interface and mechanical installation together. Resolution is the smallest reported position step; it is not the same as system accuracy.
Travel and scale length
AL200: maximum effective travel 16,384 mm. AMG5000: maximum measuring travel 82 m. Confirm the physical scale length and end allowances for the selected assembly.
Accuracy and environment
State the required system error over the working travel, temperature range, speed and mounting arrangement. Use the model-specific table rather than combining best values from different models.
Controller integration
Confirm protocol, supply voltage, timing, connector and cable length. The order code must match the receiving controller.
Already have a readhead? Specify a magnetic linear scale or encoder tape. Comparing optical feedback? Review OTV-OPE optical linear encoders.
Choose by readhead size, travel, resolution and installation gap
Start with the mechanical travel and controller interface. Resolution, accuracy and repeatability are separate specifications; compare the selected model under its stated conditions.
OTV AL200
- Resolution down to 0.1 µm
- Effective measurement length: 16.384 m
- 0.2–0.6 mm operating gap
OTV AMG5000
- Measurement travel up to 82 m
- 1 µm resolution
- 1.2 mm nominal mounting gap
OTV AL500
- 1 m measurement length; 1 µm resolution
- Operating gap below 1.6 mm
- 1.2 mm recommended mounting gap
OTV AL228
- 28 × 14 × 10 mm readhead
- 0.1 / 0.5 / 1 µm resolution; up to 2 m travel
- 0.30 ±0.10 mm recommended assembly gap
| Selection parameter | AL200 | AMG5000 | AL500 | AL228 |
|---|---|---|---|---|
| Resolution | Down to 0.1 µm | 1 µm | 1 µm | 0.1 / 0.5 / 1 µm |
| Maximum effective travel | 16.384 m (16,384 mm) | 82 m | 1 m | 2 m |
| System accuracy | ±20 to ±40 µm/m, grade dependent | ≤50 µm, configuration dependent | Confirm for selected configuration | Confirm installed accuracy with selected SC20 scale |
| Repeatability | <2 µm; <1 µm unidirectional | ≤±2.5 µm unidirectional at 1 µm resolution and 1.2 mm gap | <2 µm | Within ±1 µm at 1 µm resolution and 0.3 mm gap |
| Operating gap | 0.2–0.6 mm; 0.3 mm recommended | 1.2 ±0.3 mm nominal; 0.2–2.0 mm allowable | <1.6 mm; 1.2 mm recommended | 0.30 ±0.10 mm recommended; ≤0.8 mm maximum |
| Digital interface | SSI / BiSS-C and model-specific options | SSI / BiSS-C and model-specific options | SSI / BiSS-C and model-specific options | BiSS-C / SSI / ordered RS-485 protocol option |
| Readhead protection | IP67 | IP67 | IP67 | IP67 |
Need the scale alone? Explore magnetic linear scales and encoder tape. For light-based sensing, see absolute optical linear encoders.
Get a Linear Encoder Recommendation
Tell us your measuring travel, accuracy and resolution needs, controller interface and mounting gap. If you are unsure which model fits, describe your application and we will help narrow the options.
Your name, email and a short message are enough to start. Technical details can follow during the engineering review.
Open the enquiry form or email thomas@otvsensing.com.
Full model specifications
Readhead options and model views
View all electrical, mechanical and environmental specifications
These absolute magnetic encoder systems provide position feedback after their specified startup time without a reference run. Readhead protection is specified per model; assess connectors, scale mounting and environmental exposure for the complete installation.
Performance Parameter Comparison Table
Technical Specification | OTV AL500 | ||
|---|---|---|---|
Product Type | True Absolute Magnetic Grid Encoder System | True Absolute Linear Magnetic Encoder System | Absolute magnetic encoder for linear or circular motion |
Encoding Architecture | Dual-Track Absolute (2 mm pole pitch incremental + binary-coded absolute) | Dual-Track Absolute (5 mm pole pitch incremental + 14-bit PRBS absolute) | Absolute dual-track magnetic scale; MSA50 series, 5 mm magnetic pitch |
Readout Sensor Type | Magnetic grid sensing array | AMR sensor array (incremental) + Hall sensor array (absolute) | Absolute magnetic sensing; sensor element not specified |
Resolution | Down to 0.1 µm | 1 µm | 1 µm |
| Maximum Effective Measurement Length | 16.384 m (16,384 mm) | 82 m (82,000 mm) | 1 m |
System Accuracy | ±20 µm/m to ±40 µm/m | ≤ 50 µm (module and mounting dependent) | — |
Repeatability | < 2 µm (< 1 µm unidirectional) | ≤ ±2.5 µm (unidirectional @ 1 µm res, 1.2 mm gap) | < 2 µm |
Max. Linear Velocity | 5 m/s | 5 m/s | 5 m/s |
Position Latency / Update Time | < 62.5 µs | < 6 µs | — |
Power-Up Startup Time | < 350 ms | < 400 ms | < 350 ms |
Operating Gap (Air Gap) | 0.2 – 0.6 mm (0.3 mm recommended spacer) | 1.2 ± 0.3 mm (0.2 – 2.0 mm allowable range) | < 1.6 mm; 1.2 mm recommended |
Digital Interfaces / Protocols | BiSS-C, SSI, Tamagawa, Panasonic, RS-485 | BiSS-C, SSI, Tamagawa, Modbus-RTU, Panasonic | SSI, BiSS-C, Tamagawa, Panasonic, Modbus-RTU |
Housing Material | Stainless Steel (Epoxy resin potted) | Anodized Aluminum | Epoxy resin potted; housing material not specified |
Environmental Protection | IP67 | IP67 | IP67 |
Operating Temperature | -10°C to +55°C | -20°C to +80°C | −5°C to +70°C |
Readhead Weight | 105 g (with 0.5 m cable & DB9 connector) | Approx. 30 g (without cable) | — |
Readhead Dimensions (L×W×H) | Compact body (46 mm screw spacing) | 93 × 23 × 11 mm (86 mm screw spacing) | — |
Cable Specifications | PUR high-flex, drag-chain compatible, OD 5.0 mm | TPU high-flex, dual-shielded, drag-chain rated (≥ 20M flex cycles), OD 4.4 mm | TPU high-flex, dual-shielded, drag-chain compatible; 4.4 ± 0.15 mm OD |
| Supply Voltage | 5 V ±5% | 5 V ±5% | 5 V ±5% |
| Current Consumption | 150 mA max at 25°C | 150 mA max at 25°C | 150 mA max at 25°C |
| Maximum Cable Length | 10 m | 10 m | 10 m |
| Cable Lead Length | 0.5 m standard; customizable | 0.5 m standard; customizable | 0.5 m standard; customizable |
| Cable Output Options | Direct cable; DB9 or DB15 optional | Direct cable; DB9 or DB15 optional | Direct cable; DB9 or DB15 optional |
| Scale Compatibility | dual-track absolute magnetic scale; 10 mm wide | dual-track absolute magnetic scale; 20 mm wide | dual-track absolute magnetic scale; 20 mm wide |
| Cable Construction | 8 conductors; 0.08 mm² (28 AWG); 0.38 Ω/m | 8 conductors; 0.08 mm² (28 AWG); 0.38 Ω/m | 8 conductors; 0.08 mm² (28 AWG); 0.38 Ω/m |
| Cable Shielding | Double-shielded; 90% coverage | Double-shielded; 90% coverage | Double-shielded; 90% coverage |
| Cable Flex Life | 30 million cycles at 35 mm bend radius | 30 million cycles at 35 mm bend radius | 30 million cycles at 35 mm bend radius |
| Cable Bend Radius | 25 mm dynamic; 10 mm static | 25 mm dynamic; 10 mm static | 25 mm dynamic; 10 mm static |
Product Selection Summary for Customers
- Choose the OTV AL200 if you require:
- Ultra-high resolution down to 0.1 µm for micro-positioning feedback.
- Higher linear accuracy grades (±20 µm/m).
- Choose the OTV AMG5000 if you require:
- Extra-long travel distances up to 82 meters.
- A wider installation air gap (1.2 mm nominal) allowing for greater mechanical installation tolerances.
Complete systems and custom magnetic scales
At OTV Sensing, we offer complete, standalone magnetic absolute linear encoder solutions, including both the readhead and the precision magnetic scale.
In addition, we also supply custom magnetic scales separately—ideal for system integrators who have already selected an encoder IC or readhead and need a tailored magnetic target. Whether you need a specific pole pitch, a reduced thickness for tight spaces, or a unique length, our team can deliver a magnetic scale that integrates seamlessly with your existing electronics.
Thanks to contact OTV Sensing to discuss your requirements and find the optimal magnetic absolute linear encoder for your motion control system.
Customize the linear encoder for your installation
We understand that every application has unique constraints. OTV Sensing offers extensive customization options to ensure the encoder fits your system perfectly.
| Parameter | Customization Options |
|---|---|
| Measuring Length | Select the measuring length for the application; catalog maximums are AL200 16.384 m, AMG5000 82 m and AL500 1 m. |
| Pole Pitch | standard 2 mm, 1 mm, 1.5 mm, 5mm, or custom pitches to match specific encoder ICs |
| Magnetic Scale Width | Scale width and track layout depend on the readhead and model. Custom geometry is reviewed with the selected sensing system. |
| Magnetic Material | High‑performance ferrite rubber; optional stainless steel carrier tape for added stability |
| Output Protocol | Select from the model-specific interface options in the specification table. Other interfaces require an engineering feasibility review. |
| Cable Configuration | Custom length, shielding options, and exit orientation |
| Mounting Method | Adhesive backing, mechanical mounting holes, or protective cover tape |
From requirements to prototype validation
Requirement Analysis: We work closely with your engineering team to understand your specific needs—measuring length, resolution, accuracy, environmental conditions, and mechanical constraints.
Design & Engineering: Our engineers design the magnetic scale pattern and select appropriate materials to meet your specifications.
Prototyping: Prototype samples are manufactured for your testing and validation.
Production: Full‑scale manufacturing with 100% inspection to ensure quality consistency.
Typical applications
Magnetic absolute linear encoders are used across a wide range of industries that demand high precision and reliability:
| Industry | Application Examples |
|---|---|
| Robotics | Collaborative robots, linear actuators, positioning stages |
| Industrial Automation | Pick‑and‑place machines, automated assembly lines |
| Machine Tools | CNC machining centers, grinding machines |
| Medical Equipment | Surgical robots, imaging systems, patient positioning tables |
| Renewable Energy | Solar tracking systems, wind turbine pitch control |
| Linear Motors | High‑speed linear motion stages, direct‑drive systems |
| Packaging Machinery | Filling machines, labeling equipment |
| Automotive Manufacturing | EV battery assembly, test stands |
Linear encoder selection FAQ
1. What is the advantage of a magnetic absolute linear encoder over an optical encoder?
Magnetic sensing does not depend on an unobstructed optical path. Assess the selected readhead protection, scale mounting, magnetic interference and the actual oil, coolant or moisture exposure when comparing technologies.
2. Does the encoder require a homing sequence after power-up?
The selected absolute encoder provides its position value after the model-specific startup time, without a reference run. Confirm the specified maximum measurement length and the matching magnetic scale.
3. What is the standard MOQ for your linear magnetic encoder?
We are flexible to discuss volume-based adjustments for prototype or trial orders.
4. Can you produce custom design samples before full production? Is there a charge?
Yes, we can provide custom designsamples for validation. Samples are typically charged at a nominal fee to cover material and setup costs. Lead time for sample building is generally 4 weeks after design confirmation.
5. Can I use my own readhead with a custom magnetic scale from OTV?
Yes. In addition to complete encoder systems, we offer standalone custom magnetic scales. We can tailor the pole pitch, scale width, thickness, measuring length, and track configuration to match your chosen readhead or encoder IC.
6. What output protocols do you support?
SSI and BiSS-C are available in the listed model families. Tamagawa, Panasonic and RS-485 / Modbus-RTU availability depends on the model and ordering configuration. Check the specification table and discuss any other interface requirement with OTV Sensing.
7. What is the maximum measuring length?
Maximum effective measurement length depends on the model: AL200 supports 16.384 m (16,384 mm), AMG5000 supports travel up to 82 m, and AL500 supports 1 m. Select the actual length required for the application and confirm the matching readhead, scale and ordering configuration.
How absolute magnetic position feedback works
Magnetic sensing technologies: Hall, AMR and TMR
AMR (Anisotropic Magneto-Resistive): The sensor operates in saturation mode, typically requiring a magnetic field >300 Gauss. It responds only to the direction of the magnetic field—not its amplitude. This makes the system highly tolerant to variations in air gap and mechanical tolerances during installation.
TMR (Tunnel Magneto-Resistive): A newer technology that delivers higher signal output and lower power consumption (up to 50% reduction compared to Hall sensors). It also offers excellent temperature stability, making it ideal for applications where thermal drift must be minimized.
Hall Effect: A well-established, cost-effective technology suitable for general industrial applications where high integration and simplicity are priorities.
Example: Nonius absolute encoding
Absolute position is encoded in the magnetic scale and read by the matched readhead. The selected model determines the track layout, code structure and startup time.
In a Nonius implementation, Master and Nonius tracks have different spatial periods. The sensing electronics compare their phases to determine position within the specified absolute measurement range.
This is one implementation example. Binary-coded and PRBS track layouts are identified separately in the model specification table; the Nonius diagram should not be interpreted as the encoding architecture of every model.
Readhead and magnetic scale components
A complete magnetic absolute linear encoder system consists of two primary components:
| Component | Description |
|---|---|
| Magnetic Scale | A stainless steel carrier strip coated with bonded ferrite rubber, magnetized with precision pole patterns. Absolute coding and track geometry depend on the selected model: consult the binary, PRBS or Nonius architecture identified in the model specifications. |
| Readhead | Contains the magnetic sensor IC and signal processing electronics. As the readhead moves along the scale, the IC detects field variations and calculates absolute position in real time. |