Every system that controls motion needs to know the real position of the moving part. In a motor you need the shaft angle; in a robot, the position of the joints; in a linear actuator, how far the slider has travelled. Without this information the controller can issue a command but cannot verify whether the requested motion was carried out correctly.The position sensor closes this control loop. It measures the motion and turns it into a signal the electronic system can read. When the device provides a coded representation of position or displacement, it is commonly called an encoder.
Measures the angle of a shaft or a rotating part. Used in motors, robots, gearboxes, steering and actuators.
Measures displacement along a path, for example on a guide, a valve, a piston or a machine axis.
Provides pulses or changes relative to a previous position. To know the absolute position it may need a referencing procedure.
Returns the position directly at power-on, without having to perform a homing move.
Encoders can be based on optical, magnetic, electromagnetic or inductive principles. The choice depends on accuracy, environment, temperature, size, speed, cost and how it integrates. The solution with the highest resolution on a datasheet is not necessarily the one that keeps the best performance once mounted in the machine.
Can reach very high resolution and accuracy, especially in clean environments with precise mechanics. It does, however, require attention to contamination, vibration, concentricity and protection of the disc or scale.
Compact, mature and inexpensive in simple applications. It requires a permanent magnet and can be sensitive to external magnetic fields, thermal variations and magnet positioning tolerances.
A robust, well-established solution, suitable even for very high temperatures. It is, however, bulkier, less easy to customize and normally requires a resolver-to-digital converter.
Uses printed coils and a passive metal target. It is contactless and magnet-free, lends itself to custom shapes and to through-hole or geometries hard to cover with standard components.
An inductive encoder is normally split into two parts. The stator holds the transmit and receive coils and the read-out electronics; the target is a passive metal part fixed to the moving element. The transmit coil creates an alternating field, the target modifies it through eddy currents, and the receivers turn this change into position-dependent signals.Because stator and target do not have to touch, no precision bearings are needed inside the sensor. The target can be integrated directly into the customer's assembly, giving the designer more freedom over diameter, central bore, shape and fixing.
Inductive technology becomes interesting when the encoder must be not only accurate, but also easy to integrate and robust in the real environment. The main advantage is not a single spec: it is the combination of no contact, no magnet and geometric freedom.
Dust, oil, humidity and vibration are easier to handle than for systems that need a clean optical path.
The absence of a magnet makes the measurement suitable for applications where stray fields could disturb Hall or magnetoresistive sensors.
The coils can surround a shaft and the target can be made as a ring, avoiding expensive ring magnets or dedicated mechanics.
Rotary, linear, arc, end-of-shaft, through-shaft or side-shaft: the PCB can be shaped around the space actually available.
Stator and target are separate and contactless. There is no need to put a shaft with its own bearings inside the sensor.
In the patented EMC Gems architecture, the same signals used for position can reveal airgap, eccentricity and misalignment changes useful for condition monitoring.
Many catalogue encoders impose diameter, flange, shaft, bearings and mechanical interface. A custom inductive encoder can instead be designed around the existing geometry. Shape, outer diameter, bore, angular sector, number of periods and target are defined according to the application.iEncoder is the EMC Gems family of custom inductive position sensors. We can develop rotary, linear, arc and torque solutions, with electronics and an output that is already linearized and calibrated. Depending on geometry and mounting conditions, rotary designs can reach accuracies of the order of 0.01° or better; selected ASIC and PCB can be qualified up to 130 °C.
For extreme temperatures beyond the limits of the electronics, a resolver may remain the most suitable solution. For a simple, low-accuracy measurement at the lowest possible cost, a magnetic sensor may be more convenient. In a clean environment, with metrological mechanics and a demand for ultimate resolution, an optical encoder may keep the advantage. Inductive occupies the space where robustness, precision, customization and compact integration are needed together.
The hard part is not just drawing a coil that produces a signal, but guaranteeing that the encoder keeps the required performance with misalignments, tolerances and surrounding metals. Every iEncoder is designed with IPSMagic, the EMC Gems platform for simulation, optimization and validation of inductive encoders, then built and characterized against the customer's specification.
For those who already have the electronics and the production: we design and optimize coils and target and supply the finished, tested sensor boards.
For those who need a complete system: we develop sensor, electronics, firmware, interfaces and characterized prototypes, up to volume production.
Alongside custom projects we are adding a line of catalogue rotary and linear inductive encoders, for applications that do not require a fully dedicated geometry.
The same electromagnetic signals that make it possible to derive position also carry information about the mechanical coupling between stator, target and surrounding parts. The patented EMC Gems technology uses this information to recognize gradual changes, such as increasing eccentricity, misalignment or loosening of the fixing. The encoder can thus become an observation point for predictive maintenance, without adding a second dedicated sensor.
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P.IVA/VAT IT03026280309 |
REA UD – 359523 |
Codice SDI USAL8PV |
Cap. Soc. € 10.000,00 i.v.