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Sensor and instrumentation glossary

Definitions used across our datasheets and selection notes: enclosure ratings, signal standards and hygiene terms, each written as one standalone sentence.

Applications engineeringLast updated 2026-09-15

IP67

IP67 — Enclosure rating in IEC 60529 meaning dust cannot enter under the test conditions and a short immersion, 30 minutes at about 1 m of water, causes no harmful ingress.

IP69K

IP69K — Protection code for enclosures that survive jet washing with hot water, defined for short-range, high-pressure spray near 80 °C at prescribed nozzle angles and flow.

4-20 mA current loop

4-20 mA current loop — Analog transmission where 4 mA marks the bottom of the measurement span and 20 mA the top, so a live zero separates a broken wire from a genuine low reading.

HART protocol

HART protocol — Digital messaging that rides on the 4-20 mA loop as low-level frequency-shift keying, carrying device parameters and diagnostics without disturbing the analog value.

Modbus RTU

Modbus RTU — Serial master-slave protocol over RS-485 in which devices expose numbered registers, polled one at a time, each frame checked by a cyclic redundancy code.

Full-scale error

Full-scale error — Largest deviation between the instrument and its reference anywhere across the span, stated as a percentage of span rather than of each reading.

Repeatability

Repeatability — Closeness of repeated measurements of the same unchanged stimulus, usually quoted as a span percentage at a fixed input and condition.

Hysteresis

Hysteresis — Output difference at one and the same input depending on whether it was approached from below or from above, caused by friction-like effects in the sensing path.

NTU

NTU — Nephelometric Turbidity Unit, the scale a 90-degree scatter instrument reads when calibrated against a standard reference suspension prepared to a defined recipe.

CIP / SIP cleaning

CIP / SIP cleaning — Cleaning in place by circulating detergent, rinse and sometimes acid through the process circuit without disassembly, followed in SIP by steam bringing wetted surfaces to sterilising temperature.

Triangulation principle

Triangulation principle — Distance sensing in which a spot on the target is imaged through an offset receiver axis onto a detector; target motion slides the image, and the slide maps to distance.

EMC immunity

EMC immunity — Ability of equipment to keep working within its limits during electromagnetic disturbances such as bursts, surges and radio-frequency fields, as distinct from the emissions it creates.

Process connection

Process connection — The fitting joining an instrument to the pipe or vessel, a clamp, thread or welded diaphragm among them, defined by size, seal material and cleanability.

Calibration traceability

Calibration traceability — An unbroken documented chain linking an instrument reading to national or international references, with the uncertainty of every comparison step stated.

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Product figures quoted on other pages are illustrative sample values; the definitions here describe standards and conventions, not our measured performance.