01
Diffuse reflection
Emitter and receiver share one housing and detect light reflected by the target. Cost-effective, but target reflectivity influences performance.
ifm · Position sensing
ifm Photoelectric Sensors
Detect objects, verify presence, measure distance and solve error-proofing tasks using the optical principle that matches the target and machine geometry. ifm offers diffuse, background-suppression, retro-reflective, through-beam and PMD time-of-flight routes across compact and rugged housings.
DiffuseBackground suppressionRetro-reflectiveThrough-beamPMD distanceIO-Link by family/model
General principles4 core routesDiffuse · BGS · retro-reflective · through-beam
O6 BGS200 mmRepresentative compact background-suppression route
O6 retro5 mReflector-based detection route
O5D distanceUp to 2 mPMD time-of-flight distance / error-proofing route
Optical selection
Beam geometry selection
The biggest mistake is selecting by sensing range alone. Target colour, reflectivity, access to both sides of the object, background position and installation space determine the correct optical principle.
02
Background suppression
Use when the sensor must detect the target while ignoring a defined background behind it.
03
Retro-reflective
Sensor and receiver are in one housing and use a reflector. The object is detected by interruption of the returned beam.
04
Through-beam
Separate emitter and receiver provide long range, high operating reserve and no diffuse dead zone, but require access to both sides.
Machine applications
Photoelectric sensing spans simple presence detection through precision error-proofing
Object presence and counting
Detect cartons, components and carriers using through-beam, retro-reflective or diffuse principles according to conveyor access and object surface.
Error-proofing and part verification
Use precise laser / PMD distance sensing when the machine must distinguish correct placement, height or component presence.
WetLine and stainless routes
Use purpose-designed housings where cleaning, moisture, oils or coolants require higher environmental resistance.
Portfolio routes
Compact general-purpose sensors, rugged M18 formats and precision distance technologies
ifm's current selection spans compact O6/O8 housings, O5 rectangular sensors, OG M18 formats and PMD / laser distance families such as OGD, O1D, O5D, OPD and OMH.
O6Compact rectangular family with diffuse, background-suppression, retro-reflective and through-beam routes; industrial and metal food/washdown variants.
O5General industrial rectangular route with longer ranges in selected principles.
OGM18 barrel / cube format where a cylindrical machine-standard housing is preferred.
PMD / laserDistance measurement and error-proofing when a switching beam alone does not provide enough process information.
Representative current ranges
Range depends heavily on the optical principle
| Family / principle | Representative sensing range | Main use | Interface / note |
|---|---|---|---|
| O6 background suppression | 200 mm | Compact target detection while ignoring background | Selected models with IO-Link |
| O6 retro-reflective | 5 m | Longer-range opaque/shiny object detection | Reflector required |
| O6 through-beam | 10 m | High excess gain / beam-break detection | Emitter + receiver |
| O5 background suppression | Up to 1.8 m | Longer-range industrial detection | Rectangular housing |
| OG through-beam | Up to 25 m general-purpose route | M18-format long-range detection | Separate emitter / receiver |
| O5D PMD | Up to 2 m | Distance / error-proofing | Measured distance + IO-Link |
Engineering criteria
Define the target and background before selecting a part number
Target materialOpaque, transparent, shiny, black, metallic or diffuse surface.
DistanceMinimum / maximum target distance and available mounting space.
BackgroundDistance and reflectivity of machine surfaces behind the target.
AccessWhether both sides of the target are available for through-beam sensing.
SpeedObject speed, switching frequency and smallest detectable feature.
EnvironmentDust, oil, coolant, washdown, ambient light and vibration.
Transparent targets need special attention. Do not assume a standard diffuse or retro-reflective sensor will reliably detect clear film, glass or bottles. Use IFM's dedicated clear-object routes where required.
Selection support
Inputs required to select the correct photoelectric sensor
Send a simple application sketch or photograph
For optical sensing, geometry is often more important than a long written description. Show the target, background, sensor location and available reflector / receiver position.
FunctionPresence, counting, distance, edge, error-proofing or clear-object detection
TargetMaterial, colour, size and surface finish
DistanceNominal and variable target distance
OutputPNP/NPN, switching, analogue or IO-Link requirement
HousingMiniature, rectangular, M18 or washdown / stainless route
EnvironmentAmbient light, moisture, coolant, dust and cleaning