Glossary · Process instrumentation and analytical measurement
Sensor break
Also known as: Sensor failure, Open sensor
German: Sensorbruch
In instrumentation, a sensor break is a fault in which the sensing element or its connection is interrupted, for example a broken thermocouple or RTD wire, so that the transmitter or input can no longer deliver a valid measured value.
- Process instrumentation
In one sentence
A sensor break is an interrupted sensing element or connection, so no valid measured value is available and the device must signal a fault.
Example
A thermocouple in a furnace burns through; the transmitter detects the sensor break and drives its output to the failure current.
How it applies
- Engineering: Transmitters and input cards detect sensor breaks by monitoring currents or resistances. The reaction, such as upscale or downscale failure signal or holding the last value, is configurable and must suit the process.
- Safety: A sensor break must lead to a defined reaction. Holding the last value can hide the fault; the configured behavior should follow the fault analysis and bring the function toward a Defined safe state where required.
- Operation: Operators need a clear alarm that distinguishes a sensor break from a real process value at the limit.
- Documentation: Document the configured sensor break reaction, the alarm text and the troubleshooting steps, including how to check the sensor and its wiring.
Sensor break vs. wire break
A sensor break concerns the sensing element, possibly including its leads. Wire break detection monitors the cable between device and input. Both are open-circuit faults; they are often detected by the same mechanisms.