Sensor hysteresis vs repeatability compares two different questions about a switching sensor. Hysteresis concerns the separation between its approach and return switching positions. Repeatability concerns variation in repeated observations with the approach direction kept the same.
Keep the event, direction and reported quantity beside every value. A small number under one heading cannot answer the other question.
Start with the manufacturer’s definitions
Balluff’s inductive-sensor basics manual, printed page 10, defines switching-sensor hysteresis through the approaching switch point and receding switch-back point. Its repeat-accuracy definition concerns variation when a specified position is approached repeatedly from one direction.
Use the selected product’s datasheet and stated evaluation method for an actual comparison. The explanation below uses invented records to show why column headings matter.
Three checks in this reading exercise
1. Name the switching event and direction
Identify the complete sensor reference and the physical target described by the record. State what position coordinate the reviewer is reading.
Label the event recorded on approach and the event recorded on return. Preserve the actual signal description from the device and test documentation.
Do not use “trigger point” for every entry without saying which transition it describes. The reviewer needs to distinguish the target path from the electrical output state.
Make the coordinate readable
Show the zero reference and positive direction on the relevant drawing. State whether the listed position is a gap from the sensing face or another defined coordinate.
A value of 4.00 mm means little without that basis. Keep its unit with the number and retain the recording resolution.
For an actual review, ask the provider which target, conditions and method the product’s figures cover. Keep those details attached to the stated specification.
The sensor operating-distance guide addresses distance definitions and the target basis. Here the narrower question is how direction and repeated observations identify the reported metric.
2. Separate a return gap from a repeated-position span
Consider fictional worksheet H17. It describes a normally open switching sensor and an invented gap coordinate measured away from the sensing face.
In the invented outward-and-return record, approach means decreasing that gap. The output turns on at 4.00 mm during approach and turns off at 4.40 mm during withdrawal.
The separation between those two positions is 4.40 − 4.00 = 0.40 mm. That subtraction compares different directional transitions.
Now read the same-direction entries
A separate invented record lists three turn-on gaps from repeated approaches: 3.99 mm, 4.00 mm and 4.02 mm. All three rows refer to the same named approach event.
The largest entry minus the smallest is 4.02 − 3.99 = 0.03 mm. This is the raw span of those three fictional observations.
It is not automatically the manufacturer’s specified repeat-accuracy value. Use the actual product’s definition, evaluation procedure and reporting basis to interpret a real specification.
| Invented record | What the calculation compares |
|---|---|
| 4.00 mm approach; 4.40 mm return | 0.40 mm separation between different transitions. |
| 3.99, 4.00 and 4.02 mm on approach | 0.03 mm raw span across three repeated entries. |
These numbers are reading examples only. They are not sensor ratings, installation gaps, recommended settings or results from a JiurunCut machine.
Keep the original rows available
If a report supplies only one summary number, request the quantity name and calculation basis. Ask whether it concerns a directional separation or repeated observations.
Retain the original event labels when transferring a result into a quotation table. A new heading such as “accuracy” can remove the information that made the value interpretable.
Keep approach and return records identifiable if both are included. If the provider summarizes each direction separately, preserve those separate headings.
Do not combine the invented 0.40 mm separation and 0.03 mm span into one component-performance score. They answer different questions within the fictional worksheet.
3. Keep a sensor metric separate from machine acceptance
Identify the component record being reviewed. Then identify the actual machine function and acceptance requirement in a separate field.
A sensor datasheet can describe its stated characteristics. Request the agreed verification record for the complete delivered arrangement when the order requires one.
Follow the event through the review package
Ask which physical event the machine documentation names and which received signal represents it. Keep the relevant device and receiving-interface references available.
The PNP and NPN sensor guide covers the electrical-output comparison. A directional switching-position figure does not identify that interface.
If a quotation concerns a spare, distinguish an original approved replacement from a proposed alternative. Keep the comparison open until the responsible supplier has reviewed the complete requirement.
Do not convert an unverified sensor figure into a cutting-length tolerance or finished-part acceptance claim. Request the actual evidence for the named machine and part requirement.
Make an unresolved entry visible
Imagine an offer that lists “repeatability: 0.40 mm” but attaches only the first H17 record. Ask the provider to explain the heading and supply the intended metric’s basis.
The invented mismatch does not prove that a real sensor is defective. It shows that the attached record cannot answer the heading as written.
Keep the clarified response with the offer revision. Record who supplied the explanation and which device and conditions it covers.
Have the responsible personnel define any actual verification work using the approved documentation. This guide provides no live machine test, sensor adjustment or wiring procedure.
Send a short request with complete headings
Please identify the exact sensor and target basis. Explain which approach and return events define the stated hysteresis, and which same-direction evaluation defines the repeatability entry. Retain the units, conditions and reporting basis.
Attach the relevant component record and identify any machine-level requirement separately. Ask for missing fields to remain visible in the response.
For an aluminum cutting-machine project, send JiurunCut your section drawing and intended production workflow. Include the integration and verification scope you need the proposal to explain.
Questions about sensor hysteresis vs repeatability
Is the three-entry span an official repeatability rating?
It is a calculation from an invented sample. An actual rating needs its documented definition and evaluation basis.
Can a small return gap prove repeatability?
Request the repeated same-direction record or applicable specification. The return-gap entry answers another question.
What should stay beside the number?
For sensor hysteresis vs repeatability, retain the event, direction, coordinate, unit and actual reporting basis.