1. What Is an Absolute Magnetic Linear Encoder?
In the world of linear motion control, magnetic encoders are rapidly becoming the go‑to alternative to optical systems – thanks to their non‑contact, wear‑free operation and outstanding environmental robustness.
The OTV-AL200 Series is a true dual‑track absolute magnetic encoder system. It includes not only a readhead but also a high‑quality linear magnetic encoder strip.
Unlike incremental systems that lose position after power‑off, an absolute encoder delivers a valid, unique position value within a very short time after power‑up (typically around 350 ms) – no homing routine required.
2. Core Technology: Magnetic Linear Encoder Working Principle
The readhead integrates a sensor IC (such as the iC‑MU or iC‑MU200 series) that simultaneously reads both tracks. Using an onboard algorithm – either Nonius (vernier) calculation or direct binary decoding – the readhead instantly determines the absolute position by comparing the phase difference or the code combination of the two tracks.
Because the sensing is non‑contact, there is zero mechanical wear, and signal processing delays are extremely low (typically <62.5 µs).
The magnetic linear encoder scale or tap – a flexible magnetic strip with two parallel tracks:
Incremental track (Master track): A precise alternating N‑S pole pattern with a standard pole pitch of 2 mm. This track provides high‑resolution relative position interpolation.
Absolute track: A uniquely coded binary pattern that repeats only once over the entire measuring length.
3. Product Specifications and Performance Parameters
The OTV‑AL200 Series is engineered for stability and broad compatibility.
Below are the key parameters that matter most to your application.
| Parameter | Specification | Notes |
|---|---|---|
| Absolute resolution | Up to 0.1 µm | Supports sub‑micron precision control |
| Maximum travel speed | 5 m/s | Suitable for high‑speed linear motors |
| Unique code length | 16,384 mm | Provides a unique absolute position over a 16.38 m range |
| System accuracy | ±20 µm/m (tape accuracy) | Can be further improved with self‑calibration |
| Communication protocols | BiSS‑C, SSI, RS‑485, Panasonic, Tamagawa | Broad compatibility with mainstream controllers and drives |
| Supply voltage | 4.75 V – 5.5 V | Reverse polarity protected |
| Protection class | IP67 (epoxy potted) | Waterproof, oil‑proof, dust‑resistant |
| Readhead operating temperature | –10 °C to +55 °C | During operation |
| Readhead storage temperature | –20 °C to +85 °C | Non‑operating |
| Magnetic tape temperature range | –20 °C to +70 °C | Both operating and storage |
| Vibration resistance | 300 m/s² (~30 G) | 55 Hz – 2000 Hz (IEC 60068‑2‑6:2007) |
| Shock resistance | 300 m/s² (~30 G) | 11 ms duration |
| EMC immunity | Compliant with EN IEC 61000‑6‑2:2019 | Reliable operation in industrial interference |
| EMC emission | Compliant with EN IEC 61000‑6‑4:2019 | Robust cabling and circuit design |
| Permissible external magnetic field | <1 mT (during operation) | >25 mT may cause irreversible damage to the tape |
| Housing material | Stainless steel | Rugged, excellent EMC compatibility |
4. Installation Guide: Magnetic Linear Encoder Air Gap Tolerance Typical Values
During installation, the relative position between the readhead and the linear magnetic encoder strip is critical to achieving rated performance.
4.1 Key Installation Tolerances
Magnetic encoder performance strongly depends on the magnetic linear encoder air gap tolerance typical values:
Recommended air gap: 0.3 ±0.1mm
Lateral offset: The readhead should be centered over the magnetic tape. Excessive offset reduces the sensed magnetic field strength and can degrade accuracy.
4.2 Installation Tips
The OTV‑AL200 readhead features a built‑in status LED to help you get the alignment right:
Solid green: Signal strength is perfect – installation is correct.
Red flashing or solid red: Air gap is too large, the tape is demagnetized, or the readhead cannot detect the tape.
We recommend using a 0.3 mm feeler gauge as a reference during installation, and verifying that the LED remains green across the entire travel range.
5. Core Advantages: Precision Magnetic Scale Linear Encoder
Why choose a magnetic linear encoder over an optical system? The advantages of precision magnetic scale linear encoder are compelling:
Superior environmental robustness – Magnetic sensing does not rely on an optical path. Even in CNC machines and machining centers flooded with cutting fluid, oil mist, metal dust, or condensation, a magnetic encoder keeps working – while optical systems often fail due to contamination.
High reliability and maintenance‑free operation – The non‑contact design means zero friction. The OTV‑AL200 has a theoretical service life exceeding 100,000 hours, dramatically reducing long‑term maintenance costs.
Easier installation – Compared to the strict cleanliness and parallelism requirements of optical glass scales, a magnetic linear encoder offers much wider installation tolerances, making setup faster and more forgiving.
Shock and vibration resistance – With solid‑state sensing chips and epoxy potting, the system withstands shocks up to 50 G and vibrations up to 5 G.
6. OTV Sensing’s Custom Ordering Code System
To help you quickly specify the exact product you need, OTV Sensing has established a unique ordering code structure. Each code directly corresponds to your custom requirements.
OTV‑AL200 Ordering Code Format
OTV‑AL2 – A – B – C – D – E – F
| Position | Meaning | Example Options |
|---|---|---|
| A | Absolute resolution | R001 = 1 µm, R0001 = 0.1 µm |
| B | Supply voltage | V5 = 5 V DC, V24 = 24 V DC |
| C | Communication protocol | BISS = BiSS‑C, SSI, 485 = RS‑485 |
| D | Cable length | L2 = 2 m (default), L5 = 5 m, LX = custom length |
| E | Connector type | C0 = bare wire, C1 = DB9 male, C2 = DB15 |
| F | Special customization | S = adhesive‑mount scale, V = bolt‑mount scale |
Example order code:OTV‑AL2‑R0001‑V5‑BISS‑L5‑C1
→ OTV AL200 series, 0.1 µm resolution, 5 V supply, BiSS‑C protocol, 5 m cable, DB9 connector.
7. Customization: Beyond Standard Products
We can customize absolute linear encoder products for your application, which primarily involves customization of the magnetic scale, including but not limited to the following items:
Length customization: Single strips up to 50 meters long.
Material options: Choose between NBR elastomer‑bonded ferrite or high‑performance materials, depending on your environment.
Magnetic scale assembly : We offer 3M high‑strength adhesive backing, or screw assembly.
- Protective cover ：if needed,a 0.3 mm thick stainless steel cover tape can be applied– ideal for protecting the magnetic tape in abrasive or sliding contact environments.
If you have further customization requirements for our linear magnetic encoder strip or magnetic linear encoder scale, or if you need detailed mechanical drawings for installation, please don’t hesitate to contact our engineering team.
We’re here to help you achieve the precision and reliability your application demands.
FAQ
1.What is the advantage of a magnetic absolute linear encoder over an optical encoder?
Magnetic encoders are inherently more robust in harsh environments. They are not affected by dust, oil, moisture, or condensation. They also tolerate larger installation tolerances and are less sensitive to vibration, making them ideal for industrial automation, robotics, and outdoor applications.
2.Are the standard ic-haus ic-mu chip suitable for angle measurement?
The IC-MU200 chip can be used for both absolute angle measurement and absolute linear displacement measurement. Linear magnetic scale need to be used for linear absolute position measurement.
3.What is the standard MOQ for your magnetic linear encoder?
We are flexible to discuss volume-based adjustments for prototype or trial orders.
4.Can you produce custom desgin 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.What is the typical lead time for standard magnetic encoder orders?
For standard products with no stock, the lead time is 2 weeks after order confirmation and receipt of deposit.
6.Can I request custom magnetic scale specifications for the linear encoder ?
Yes,we fully support customization for parameters such as dimension,protections, mounting hole positions, thickness, and magnetic properties to meet specific application needs.