A defined target, supply, load, approach direction, adjustment state and environment create a comparable reference.
Factory verification guide
How Proximity Sensors Are Calibrated Before Shipment
Understand what a factory setting proves, what final inspection should check, and when your real target still requires field teach-in or a customer-specific test.
Short answer
Many proximity sensors are factory set and function-tested under defined, model-specific conditions. That establishes a repeatable release baseline. It does not prove the same switching point with every target, bracket, temperature, buildup level, cable run, or PLC input.
Image: Radarvector, crop by Pittigrilli, via Wikimedia Commons, CC BY-SA 4.0. Laboratory instruments can verify electrical behavior; target-based sensing tests are still required.
Identity, switching action, reset action, output behavior and traceability support release of the correct product.
The installed sensor must still detect the real target with enough margin across normal machine variation.
Ask for the right evidence, not just “calibration.”
The word calibration is often used for four different activities. Start with the decision you need to make, then request the matching test record. This prevents a routine factory inspection from being mistaken for target-specific application approval.
Confirm the model, electrical output and supplier's routine final-test coverage.
Then commission on the machine.Define the actual target, approach, mounting gap, supply, load and acceptance band.
Request recorded results.Teach or tune the threshold with the real product and background in worst-case states.
Record the final setting.Specify identification, method, results, tolerance, traceability and uncertainty where applicable.
Agree this before quotation.“Factory calibrated” can describe four different things.
The practical distinction
A factory may adjust an internal threshold, verify a finished sensor, issue a test report, or provide a traceable calibration certificate. These are related activities, but they are not interchangeable evidence.
For a switching sensor, the factory's main job is usually to establish and verify predictable behavior under controlled conditions. The test may include the switching point, reset point, hysteresis, output logic, indicator, current consumption or communication status. The exact checks depend on sensor type, model and supplier control plan.
IEC 60947-5-2 provides a product-standard framework for several non-contact proximity-switch technologies. It does not give one universal pre-shipment routine for every factory and every application.[1] Ask the supplier which characteristics are checked on every unit, which are sampled, and which were established during design qualification.
Factory setting
Internal or external adjustment that places the sensor near its intended model baseline.
Sets a starting pointFinal functional test
Checks whether the finished unit switches, resets and produces the expected output under defined conditions.
Supports shipment releaseCalibration certificate
A controlled document reporting identified equipment, method, conditions and results, with traceability and uncertainty when required.
Must be specifiedField teach-in
Sets the threshold using the actual product, background and installed geometry.
Validates the applicationImportant: a standard proximity sensor test is not a machine-safety validation. Safety-related sensing functions require the correct safety device, architecture, standards, risk assessment and validation.
Reference conditions change
The sensing principle determines what the factory must control.
There is no single target or adjustment method that represents every proximity sensor. The controlled input must match the physical principle used by the product.
TechnologyUseful factory referenceWhat still changes in the machine
Inductive
Defined metal target, target size, approach direction, mounting class, supply and load.
Metal type, target thickness and area, side approach, surrounding metal, temperature and vibration.
Capacitive
Defined test material, distance, sensitivity setting, supply and switching behavior.
Dielectric constant, target area, wall thickness, moisture, residue, grounding and nearby material.
Photoelectric
Emitter and receiver condition, reference target or reflector, alignment, threshold and output.
Color, gloss, angle, background, contamination, ambient light, vibration and target speed.
Ultrasonic
Reference target, distance, alignment, response and configured window or switching point.
Target angle, surface shape, air movement, temperature, vapor, foam and acoustic interference.
Magnetic
Defined magnet, pole orientation, approach path, operating point, release point and output.
Magnet grade, gap, orientation, nearby ferrous material, shock, temperature and mechanical travel.
Product scope reference: IEC 60947-5-2:2019.[1]
Inductive example
A sensing-distance number only makes sense with a defined target and method.
For an inductive proximity sensor, the target is moved toward and away from the active face under controlled conditions. The switching and release positions are recorded. Target material, dimensions and approach direction matter because they change the electromagnetic coupling.
- Standard sensing object: a defined target used to establish a comparable characteristic.
- Sensing distance: the position where the output changes as the target approaches.
- Reset distance: the position where the output returns as the target moves away.
- Hysteresis: the separation between the operating and release positions.
- Assured operating range: the range intended to be reliable after specified variation is considered.
H = |xON - xOFF|Keep the target path, speed and reference point consistent when comparing switch and release positions.Terminology and target behavior: Omron proximity-sensor terms and Pepperl+Fuchs operating distance guide.[2][3]
DEFINED METAL TARGET
Controlled axial approach
Move the target through the sensing zone, then reverse the motion without changing the path.
xONOutput changes during approachxOFFOutput resets during withdrawal
Typical final verification
Seven steps from product identity to shipment release.
A supplier may combine or automate these operations. The important point is that each released unit must be connected to the right model requirements and an approved test method.
Identify the device
Confirm model, output, cable or connector, housing, lot and configuration.
Power and load
Apply the defined supply and representative output or communication condition.
Present the target
Use the specified target, distance reference, approach direction and fixture.
Check switching
Verify operate and release behavior, adjustment range and hysteresis where required.
Verify the output
Confirm logic, indicator, voltage or current behavior and communication data.
Record traceability
Link results or pass status to the unit, batch, order or controlled inspection record.
Release and pack
Protect settings, face, cable and connector after quality approval.
Do not assume every characteristic is tested on every unit. Routine output and function checks may be 100% while environmental endurance, EMC, life or destructive tests are normally design-qualification or sampling activities. Ask for the supplier's actual control plan.
Factory evidence
A clean production line is useful context. A controlled result is stronger evidence.
Factory photographs show capability and organization, but they do not reveal the target, tolerance, test frequency or acceptance rule used for your order. For a critical application, connect the visual audit to documented evidence.
- Approved drawing and exact part number
- Controlled test fixture and current work instruction
- Calibrated measurement equipment where measurement traceability is required
- Clear unit, batch or order traceability
- Defined handling of failed or adjusted units
Do not mix test levels
“Tested” is incomplete unless you know when and how often.
A mature quality plan separates design proof, process monitoring, final unit checks and any customer-specific acceptance test.
Design or type qualification
Establishes the product design against defined electrical, mechanical, environmental and performance requirements.
Usually periodic or design-change drivenProduction process control
Monitors materials, assembly, settings and process characteristics that influence finished sensor behavior.
May be in-process or sampledFinal functional verification
Checks the completed orderable unit for identity, basic function, switching and output characteristics defined by the control plan.
Ask which checks are 100%Customer-specific inspection
Uses an agreed target, geometry, electrical setup and acceptance band for a particular order or application.
Must be agreed before shipmentA quality-system certificate is not a product test report. ISO 9001 defines requirements for a quality management system, but it does not prescribe the exact sensor test you need for a specific target.[7]
Factory baseline vs application threshold
Field teach-in is not a correction for bad factory work.
Adjustable sensors are designed to learn the signal separation in the real application. A factory can verify that the adjustment system works; it cannot know every future product color, hopper wall, residue layer, reflector angle or background.
Photoelectric teach modes can measure returned light across target and background states, then place a switching threshold between them. Capacitive adjustment must account for the actual material, target area, wall thickness, moisture and nearby structure.[5][6]
- Teach the worst normal statesUse the darkest, glossiest, smallest or least favorable target and the strongest normal background.
- Keep usable marginDo not place the threshold exactly on either signal. Allow for vibration, dirt, drift and production variation.
- Record the setupSave sensitivity, mode, mounting position and test target in the commissioning record.
Write a testable request
A customer-specific test needs six defined inputs.
“Please calibrate before shipment” leaves the supplier to guess. A short, measurable request gives both sides the same pass/fail rule and makes the result reusable during incoming inspection.
Include drawings or samples when shape, surface, angle or mounting metal can change the response.
Model, output, cable or connector, software or teach mode, quantity and traceability level.
Material, dimensions, thickness, color, finish, temperature and acceptable sample variation.
Approach direction, angle, gap, speed, bracket, surrounding metal, background or reflector.
Voltage, NPN or PNP, NO or NC, PLC input or load, cable length and communication settings.
Temperature, contamination, ambient light, vibration, repetition count and approach speed.
Switch band, hysteresis, repeatability, recorded units, report format and approval method.
Choose the document by risk
Do you need a test record or a calibration certificate?
Most standard switching applications need clear product data, supplier final-test coverage and machine commissioning. Traceable calibration documentation should be requested when a contract, audit, regulated process or measurement function requires it.
A final-test or inspection record may be enough
Use this route when the goal is to confirm that the supplied sensor matches the order and passes agreed functional checks.
- Exact model and quantity
- Lot, date or serial traceability
- Test method and reference condition
- Pass/fail result or measured values
- Authorized release
Specify the certificate before quotation
A useful certificate identifies the device under test and states what was measured, how, under which conditions and with what result. Where metrological traceability is required, the document should also address standards and measurement uncertainty.
- Manufacturer, model and serial number
- Procedure, equipment and environmental conditions
- Results, tolerance and conformity statement
- Traceability and uncertainty where applicable
- Date, facility and authorized signatory
General certificate-content reference: Fluke calibration overview.[8]
Three real buying situations
The right release evidence depends on what can go wrong.
Use these examples to decide whether a normal catalog check, field teach-in or customer-specific pre-shipment test is appropriate.
M18 sensor reading a steel cam
The catalog model is factory verified with a defined target. The machine still needs an assured installation gap that allows for cam runout, bracket movement, temperature and surrounding metal.
Best evidence: final function + installed margin checkLiquid through a plastic hopper wall
The final unit can be checked before shipment, but wall thickness, liquid dielectric behavior, residue and nearby grounded metal strongly influence the installed threshold.
Best evidence: function test + field teach-inGlossy dark packaging on a conveyor
A standard reference target cannot represent every print, seam, angle and background reflection. Provide samples and conveyor geometry when missed or double counts are expensive.
Best evidence: sample test + worst-case commissioningPut these eight items in your RFQ.
This checklist lets a sensor manufacturer judge whether the standard model and routine factory test are sufficient, or whether your order needs samples, a special fixture, recorded values or a certificate.
Target details
Material, size, thickness, color, gloss, shape and expected variation.
Required operating gap
Normal, minimum and maximum distance plus mechanical tolerance.
Mounting geometry
Flush or non-flush, bracket, angle, surrounding metal, background and available space.
Electrical interface
Supply, PNP or NPN, NO or NC, PLC input, load, cable and connector.
Machine timing
Target speed, event duration, switching frequency and controller scan requirements.
Environment
Temperature, washdown, dust, oil, vibration, ambient light and buildup.
Acceptance rule
Switching band, hysteresis, repeatability, margin and sample quantity.
Required document
Datasheet, inspection report, measured results, certificate or sample-test video.
Avoid expensive assumptions
Five common mistakes when buyers review factory calibration claims.
Treating nominal range as a guaranteed gap
Use the assured operating range and application margin, not only the headline distance.
Ignoring the test target
A steel reference plate does not represent aluminum foil, a tiny screw or an angled cam.
Assuming “tested” means 100%
Ask which checks are per unit, sampled, periodic or design-qualification only.
Skipping field teach-in
Adjustable sensors still need the real target and background after installation.
Requesting a certificate too late
Special fixtures, serial traceability and third-party work can affect price and lead time.
Application-first support
Send the target and acceptance rule before the order is released.
xsz sensor can review the target, distance, mounting, output, environment and requested evidence before recommending a proximity sensor or planning a customer-specific pre-shipment check.
Continue the selection process
Use these guides to define your acceptance conditions.
Frequently asked questions
Proximity sensor calibration FAQ
Are proximity sensors calibrated before shipment?
Many proximity sensors are factory set and function-tested before shipment, but the exact process varies by sensor type, model and supplier. Ask whether the checks are performed on every unit or by sampling and whether measured values are recorded.
What is the difference between factory calibration and field teach-in?
Factory calibration or setting establishes behavior under controlled reference conditions. Field teach-in sets or confirms the threshold with the real target, background, mounting and environment. Adjustable capacitive and photoelectric applications often need both.
How is inductive proximity sensor distance tested?
A defined metal target is moved toward and away from the sensing face using a controlled path. The operating and release positions are checked under specified electrical and mounting conditions. Target material, size and approach direction must be stated.
Does a 10 mm sensor always switch at exactly 10 mm?
No. The headline distance is usually a nominal or rated reference value. Real switching position changes with manufacturing tolerance, target material and size, voltage, temperature, mounting and approach. Design the machine around the assured operating range and an application margin.
Do all factories test every sensor?
Not necessarily for every characteristic. Basic function and output checks may be 100%, while environmental, endurance, EMC or destructive tests are usually handled through design qualification, periodic testing or sampling. Request the actual control plan.
Can a calibration certificate be supplied?
It may be available as a standard, optional or custom service. Specify the required identification, method, results, tolerance, traceability, uncertainty and accreditation needs before quotation because they can affect cost and lead time.
Why must a capacitive sensor be adjusted after installation?
The installed response depends on the target dielectric behavior, area, distance, wall thickness, moisture, buildup, nearby material and grounding. A factory reference cannot reproduce every hopper, container or product.
Is EMC tested on every sensor before shipment?
Complete EMC qualification is normally a design or type-level activity rather than a full test on every unit. Routine production controls may check related electrical characteristics, but buyers should review the model's declaration and supporting evidence for the applicable requirements.
What should a customer-specific sensor test request include?
Include the exact sensor, target, geometry, mounting, electrical interface, environment, timing, acceptance band, sample quantity, traceability and required report format. Samples or drawings are useful when surface, shape or angle affects detection.
Technical references
Primary sources used for this guide
- IEC 60947-5-2:2019, Low-voltage switchgear and controlgear - Control circuit devices and switching elements - Proximity switches.
- Omron, Proximity Sensors: Explanation of Terms.
- Pepperl+Fuchs, Operating Distance as the Central Characteristic.
- ifm, Inductive Sensor Technology Overview.
- Banner Engineering, Dynamic Teach Mode guide.
- SICK, Photoelectric Sensors and Teach-in Technical Information.
- ISO, ISO 9001 explained.
- Fluke, Temperature Calibration Overview.
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