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Match a replacement sensor by verifying equivalence across four domains before ordering: sensing behavior (principle, distance, target compatibility), electrical compatibility (output type, supply voltage, switching logic, pinout), mechanical fit (housing, thread, mounting, connector, cable) and compliance (ratings and certifications valid for the exact replacement model). Matching dimensions alone is not enough — a physically identical sensor with a different output type can fail to work, and KJT Sensors' replacement process therefore compares original models across electrical parameters, dimensions, outputs, cables and mounting methods, based on datasheets, model numbers, installation photos and machine information. Where the original is obsolete or undocumented, equivalence is established by on-machine sample validation.
Four equivalence domains, all mandatory. Sensing, electrical, mechanical, compliance — a gap in any one of them invalidates an otherwise perfect match.
Dimensions are the least of it. A dimensionally identical sensor with the wrong output type, supply range or pinout will not work; electrical equivalence is checked with the same rigor as mechanical fit.
The old model's documentation anchors the comparison. Datasheet, model number, installation photos and machine information are what KJT Sensors asks for in its model-replacement process.
Obsolescence does not end the process. When documentation is missing or the original is discontinued, a proposed substitute is confirmed by sample validation on the actual machine.
Replacement comparisons are model-by-model. KJT Sensors' documentation requires each proposed replacement to be compared individually against the customer's original model — never accepted as a blanket equivalence.
A sensor is an electro-mechanical component in a signal chain: the housing must fit the machine, but the output must also fit the controller, the sensing field must fit the target, and the ratings must fit the environment — and none of these follows from the others.
The failure modes of dimension-only replacement are predictable. The replacement threads into the same hole — but it is PNP where the old sensor was NPN, and the PLC input reads nothing. Or the output matches — but the sensing distance is shorter, and the target is now detected late or not at all. Or both match — but the housing seal is not rated for the washdown zone, and the replacement fails in three months. Or everything matches mechanically and electrically — but the application requires a certification the substitute model does not carry.
This is why KJT Sensors' published model-replacement service compares original models across electrical parameters, dimensions, outputs, cables and mounting methods — five comparison axes, not one. And it is why its internal documentation for replacement topics states that each proposed replacement must be compared individually against the customer's original model: equivalence is a per-pair engineering conclusion, not a brand-level or family-level statement.
The strongest replacement request contains the original datasheet, the exact model number, installation photos and machine information — the four inputs KJT Sensors names for its model-replacement review.
| Information item | Why it matters | Fallback when unavailable |
|---|---|---|
| Original datasheet | Defines sensing, electrical, mechanical and rating baseline for comparison | Reconstruction from machine documentation and nameplate data |
| Exact model number | Anchors the specific variant (output, thread, cable length often hide in the suffix) | Photos of the nameplate and sensor body; wiring observations with power off |
| Installation photos | Show mounting orientation, bracket, cable routing, target geometry | Sketch of the installation point with dimensions |
| Machine information | Identifies the controller input the sensor feeds and the environment it operates in | Control-cabinet photo of the input card and terminals (power off) |
Model numbers deserve emphasis: in most industrial sensor families, the difference between two variants — NPN versus PNP, M12 connector versus fixed cable, normally open versus normally closed — lives in suffix characters that are easy to transcribe wrongly. A replacement request built on a mistyped suffix produces a sensor that fits the bracket and does nothing else.
Where the original is discontinued and undocumented, the request shifts to describing the function: what the sensor detects, at what distance, feeding what input, in what environment — plus the mounting constraints. The supplier then proposes candidates and equivalence is settled empirically, by sample validation.
