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Absolute position feedback
Absolute rotary encoders report true shaft position the moment power is applied, so an axis never has to be driven to a reference mark before the control can trust it. Sensor Measurement supplies and supports single-turn and multi-turn absolute encoders from TR Electronic across Australia and New Zealand, with application advice from our Perth-based team.
What it does
An absolute rotary encoder assigns a unique code to every shaft position and reads that code optically or magnetically. The value is available as soon as the encoder has power, which removes the homing move that an incremental encoder needs after every stop, power failure or emergency condition.
Because each position has its own code, a missed edge or an electrical disturbance cannot quietly shift the reference the way it can with a pulse train. The control either reads a valid position or it reads a fault, which is why absolute feedback is common on safety-related and multi-axis machinery.
Single-turn devices report position within one revolution. Multi-turn devices also count revolutions, so total travel is retained over long axes, geared drives and lifting equipment.
Types we supply
Single-turn absolute encoders report an unambiguous position value for one full revolution of the shaft. Position is available immediately at power-up, so the axis never needs to be driven to a reference mark before the control can trust its reading.
Multi-turn absolute encoders keep counting revolutions as well as the position within a revolution, so total travel is retained across a power cycle. This suits long-travel axes, geared drives, cranes and lifting equipment where a homing routine is impractical.
Heavy-duty absolute encoders use sealed housings, robust bearings and wide temperature ratings for washdown, vibration, dust and outdoor plant. Versions with higher protection classes and stainless housings are selected where contamination or cleaning is routine.
Interfaces
The encoder has to speak the language of the drive, PLC or motion controller already on the machine. We confirm the exact variant against your hardware before an order is placed.
PROFIBUS, PROFINET, EtherCAT, EtherNet/IP, CANopen and Modbus variants let the encoder sit directly on the machine network, with position, speed and diagnostics read as process data rather than pulses.
SSI and BiSS-C remain the standard choice where a controller or drive expects a fast, deterministic position word. They are simple to diagnose and are widely supported by motion controllers.
Some applications need an analogue position signal or a pulse output from an absolute device. These variants let an older control platform gain absolute feedback without a full controller upgrade.
Selection checklist
Bring these details to a conversation with our team and the shortlist usually narrows quickly.
Typical applications
Absolute feedback keeps ram and backgauge position known at every power-up, which matters for repeatable bend depth and for guarding systems that rely on measured position.
Multi-turn absolute encoders track hook height and travel without limit switches or homing runs, and retain that position through shutdowns and power interruptions.
Absolute rotary encoders paired with a rack, belt or screw provide position feedback for slides, tool changers and rotary tables where re-referencing costs cycle time.
Absolute position is available on start-up, so actuators move to the commanded position without first searching for an end stop.
Position, speed and direction come from one device, with the absolute value available to the control after a stop or an emergency condition.
Sealed absolute encoders with wide temperature ranges and robust bearings suit equipment exposed to weather, vibration and washdown.
Comparison
Both are rotary encoders, and both are right for different jobs. The deciding question is whether the machine can afford to re-reference its axis after every stop.
Still comparing types? The rotary encoders Australia page covers the full range, and the incremental encoders page goes deeper on pulse-based feedback.
Ready to talk?
Send through the controller, mounting, travel and environment and our team will come back with a suitable absolute encoder option.
