01
Robot & axis feedback
Track angular or linear movement through a shaft, roller or mechanical transmission.
ifm · Motion control
ifm Rotary Encoders
Rotary feedback for position, speed, direction and counting tasks. Select incremental or absolute measurement first, then choose shaft style, resolution, interface, environmental class and whether IO-Link diagnostics are required.
IncrementalAbsolute single-turnAbsolute multi-turnIO-LinkBasic / Performance / WetLine
Incremental1…10,000 pprProgrammable on current ifm routes
AbsolutePosition retainedSingle-turn and multi-turn architectures
High speedUp to 12,000 rpmTTL incremental route per current ifm guidance
Smart dataIO-LinkPosition, speed and diagnostics by family
Selection first
Incremental or absolute?
This is the main architecture decision. Do not choose by housing diameter before deciding what the controller must know after power loss.
| Encoder route | Position behaviour | Current ifm direction | Best fit |
|---|---|---|---|
| Incremental | Relative pulses from a reference | BasicLine, PerformanceLine and WetLine; configurable HTL/TTL and resolution on current routes | High-speed motion, counting, relative position |
| Incremental + IO-Link | Can expose absolute single-turn position in current ifm architecture | Standard 3-wire / M12 communication plus configurable encoder functions | Flexible machine builds and diagnostics |
| Absolute single-turn | Absolute position within one revolution | SSI / fieldbus / current family dependent | Rotary position where no homing is desired |
| Absolute multi-turn | Absolute position across multiple revolutions | Current IO-Link multi-turn family retains position through power loss and shaft movement | Lifts, long travel, repeated turns |
| Safety encoder | Safety-related position/speed feedback | Separate safety-rated mobile/CANopen route; verify required PL/SIL | Mobile/safety architecture only when the complete safety function requires it |
Machine applications
Rotary encoders in the system architecture
Encoders are useful where the controller needs more than simple presence: angular position, direction, speed, counting or travelled distance.
02
Conveyors & drives
Measure rpm or frequency and compare it with process or drive targets.
03
Packaging & converting
Use pulse or internal counter functions for length, cycles and material handling.
04
Gates & rollers
Maintain repeatable machine settings such as web handling, gate position or roller synchronisation.
Signal architecture
Incremental pulses and absolute words solve different control problems
Incremental encoders typically provide A/B quadrature and an index channel. Absolute encoders encode a unique position value so the controller does not need to infer position from a home reference after power loss.
A / BQuadrature pulse channels indicate movement and direction.
Z indexOne reference pulse per revolution on a conventional incremental encoder.
Absolute valuePosition is directly available without a separate homing movement.
31-bit IO-Link multi-turnCurrent ifm multi-turn IO-Link architecture uses 16 bits per rotation plus 15 bits for number of rotations.
IO-Link benefits
Configure and diagnose the encoder digitally
Current ifm IO-Link encoder families add more than a digital position word.
01
Reduce variants
Set resolution, HTL/TTL mode and rotational direction on supported incremental encoders.
02
Expose operating data
Supported IO-Link encoders provide data such as bearing operating time, device temperature, total operating time and shaft speed.
03
Reduce PLC processing
Setpoints for speed, position or counts can be stored and evaluated inside suitable encoders.
Environment & mechanics
Housing and shaft mechanics matter as much as protocol
Confirm the mechanical connection before selecting the electrical interface.
Shaft typeSolid, hollow or through-hollow shaft and exact diameter.
Housing36.5, 42 or 58 mm routes depending on family.
SpeedMaximum shaft rpm and acceleration.
EnvironmentWetLine for harsh/wet use; confirm IP rating on exact model.
InterfaceHTL/TTL, IO-Link, SSI, CANopen, PROFINET or other current absolute route.
ResolutionPulses per revolution, bits per turn and number of turns required.