IncOder® Inductive Angle Encoders

Non-contact, inductive angle encoders for high-precision, reliable measurement in harsh environments.

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incoder inductive angle encoder group

Robust Angular Position Measurement for Extreme Environments

Zettlex IncOders are non-contact devices for precision angle measurement. They work like a transformer, using an inductive technique. IncOders may be considered as an inductive angle encoder.

IncOders are ideally suited to harsh environments – where potentiometers, optical or capacitive devices may prove unreliable.

inductive angle encoder

High-reliability Inductive Angle Encoder Technology

IncOders have 2 main parts – a Stator and a Rotor – each shaped like a flat ring. The large bore makes it easy to accommodate through-shafts, slip-rings, optical-fibres, pipes or cables.

The Stator is powered and the Rotor is passive. The Stator contains the electronics to receive power and generate an output signal. The output signal from the Stator shows the true absolute angular position of the Rotor relative to the Stator without the need of any motion.

Simple Installation; ‘Fit and Forget’ Technology

IncOder inductive angle encoders do not require compliant or special couplings and the Rotor & Stator can simply be screwed to the host product. Precise mechanical mounting is not required and there are no bearings.

Whereas optical or capacitive angle encoders can be unreliable in harsh conditions – notably with condensation or dust – Zettlex angle encoders are generally unaffected by foreign matter and IP67 rated versions are available. Unlike capacitive devices, there is no need to earth the Rotor or Stator. Robust, hard-anodized aluminium alloy housings and monolithic constructions are used throughout.

There are no contacting, delicate or wearing parts, so there is no need for periodic replacement, service or maintenance. In other words, IncOder angle encoders are true ‘fit and forget’ devices.

IncOder Inductive Angle Encoders

Inductive Angle Encoder Specifications / Options

Mechanical Formats
12 mechanical formats featuring screw or servo clamp Stators with screw format, set screw, shaft clamp and plain Rotors, duplex Stators and Rotors.
Packaged formats include servo clamp or screw flange.

IncOder Size Options (Stated as Outer Diameter)
37, 58, 75, 90, 100, 125, 150, 175, 200, 225, 250, 300, 325, 379, 429 & 595mm

Resolution Options
9 to 22bits & user selectable pulses per rev for A/B pulse outputs

Connection Options
Axial connector, radial flexi (with or without connector) & integral axial cable

Voltage Options
5, 12 or 24VDC

Communication Interface Options
Analogue voltage
A/B/Z pulses

Extended Range Options
(Not Typically Required for Most Application Types)

Ultra high shock & vibration
Cold temperature option to -60° Celsius
High temperature option to +105° Celsius
Leaded solder
Burn in prior to acceptance testing
Surtec650 surface finishes
Prolonged immersion, salt spray or extreme dust conditions
High Pressure

CAD Files

We have a comprehensive library of 3D CAD files available to assist designers in the integration of our inductive angle encoders. Click the button below to view available files, or contact us if you’re looking for something specific that is not listed.

CAD Files


Have a question about the IncOder product range? Here we answer a selection of frequently asked questions.

If your question doesn’t appear, please get in touch with one of our experts.

Ask an Engineer

The term IncOder comes from a combination of inductive and encoder. Most angle encoders use optical or capacitive techniques and these can be unreliable in harsh environments where foreign matter, such as dirt or condensation, can interfere with encoder operation. Traditional inductive position sensors, such as resolvers or LVDTs, use transformer constructions and they operate well in harsh conditions but they are too bulky and expensive for many applications. IncOder offers the best of both worlds – reliable inductive technology but the ease, compactness and convenience of an encoder.

Ultra IncOder Series features the same form, fit, and function device as the original rugged IncOder Series, but with at least a 50% improvement in accuracy. Taking advantage of high measurement repeatability, each Ultra IncOder is pre-calibrated against a highly accurate measurement reference in production, diminishing inherent sources of non-linearity. More tightly controlled tolerances, in-housing metalwork, and surface finish are employed in the design, enabling users to install the encoder to tighter mounting tolerances required. An accuracy certificate is included with each unit.

Ultra IncOders are available in Mini (37 to 58 mm OD) and Midi (75 to 300 mm OD) sizes.

Click for further details of our Ultra IncOders.

By default, IncOder only outputs Single Turn position data, being angle position data over 1 rotation (360 degrees). Multiturn encoders have the ability to count Multiturn data (the number of complete rotations of the sensor). Multiturn IncOder options are available for our Midi IncOder series by specifying the following protocol production options: SSI31, SSI32, SPI31, ASI31, ASI32 or BIS32. SSI based options provide 8 bits of turn count (0-255). BiSS, SPI and ASI options provide 12 bits of turn count (0-4095).


Conventional multiturn devices are able to increment Turn Count data when the device isn’t powered, which is not the case for Multiturn IncOder where Turn Count data doesn’t change when the device isn’t powered.


When power to Multiturn IncOder devices is removed, this event will be detected and position information is stored in non-volatile memory. Once the device is powered again, this data is recovered.


Note that if the Midi IncOder moves >1.5 degrees, an error condition will persist. The Midi IncOder will continue to indicate this error until the error is reset. Further details of this process can be found in our product guides.

Midi IncOder

Midi Ultra IncOder

IncOders work in a similar way to brushless resolvers and rotary variable transformers.  The IncOder Stator receives a DC power source and produces a low power AC electromagnetic field between the Stator & Rotor. This field is modified as the Rotor rotates.  The field is sensed by the Stator and the rotation angle output as an analogue or digital signal.  Unlike resolvers, IncOders use laminar circuits rather than wound wire spools. The patented technology enables IncOder’s compact form, low mass, low inertia and high accuracy without high precision installation.

Please see our “How Inductive Sensors Work” article here:

Yes. Measurements will be the same before and after power interruption. No motion is needed at start up.

For further reading – What is an absolute encoder?

Yes. If BIT shows an internal error then an error signal is generated. The BITs include continuity/damage, presence of Rotor, in-range Rotor, gross electromagnetic malfunction, window watchdog timer, power on reset, power brownout reset, timeouts for clock input, read/write and internal flash data memory value checks.

Measurement performance is unaffected by humidity, condensation, dirt, dust, oil, mud or sand. All IncOders will survive temporary immersion to depths of 1m in salt or fresh water. Where frequent exposure to liquids, or immersion, is part of the operating environment, units with connections type AFL or VFL should be used.

No. Magnets produce DC fields.  IncOder’s operation is based on the detection of AC electro-magnetic fields at a highly specific frequency.

Use this document as a basis and specify any differences. Preferably, a standard outer diameter ‘A’ dimension (i.e. 37, 58, 75, 100, 125 mm etc.) and a proportionate inner diameter should be used. This enables us to use regular sensor components with analternative mechanical format.

Resolution, repeatability & accuracy (linearity) will be as specified, provided Rotor concentricity is within specified limits. One might expect accuracy to degrade significantly with concentricity, but IncOders use the full faces of Rotor & Stator, so errors are nulled by diametrically opposing factors. This is different to other encoder technologies – notably optical or capacitive devices – where performance depends on tightly controlled concentricity.

Yes. IncOders are regularly used for UAVs.

Yes – simply specify a radial connection Product Option such as RFC1, RFC2 etc. in the part number.

Yes. Many IncOders are used near powerful sources of electromagnetic noise such as motors or transformers. IncOder’s aluminium housing produces a Faraday cage effect around the internal electronics and the technology is designed so that incoming, far-field radiation is self cancelling or filtered out.

The longer the transmission distance (Cable Length), the slower the recommended Baud Rate. This table shows recommended Baud Rates vs. Cable Length.

Cable Length (m)<30<60<120<250
Baud Rate<400 kHz<300 kHz<200 kHz<100 kHz

    Buy Now – Over 500 million angle encoder variations. Which one suits your project?

    IncOder® Series – Robust and precise inductive angle encoders

    Ultra IncOder® Series – Pre-calibrated IncOder for increased accuracy