- Ultrasonic
- Sensing technique using high frequency sound waves as
the sensing medium. It can be used in either through beam or
proximity configurations.
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- Undershoot
- The amount by which a process variable falls below the
setpoint before stabilizing.
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- Underwriter's Laboratories, Inc. (UL)
- A non-profit organization that establishes, maintains and operates laboratories for the examination and testing of devices, systems and materials primarily for safety.
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- Ungrounded Thermocouple
- A thermocouple construction in which the measuring
junction is enclosed in a protective layer and electrically
isolated from the sheath.
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- Unidirectional Differential Pressure Sensor
- A differential pressure sensor requiring the greater input pressure to be applied to a specified pressure port.
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- Uninterruptible Power Supply (UPS)
- Battery-backed device used to keep critical equipment, including computers, running in the event of a mains power failure.
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- Unipolar
- A signal range that is always positive or always negative, for example 0 to +10 V.
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- Universal Asynchronous Receiver/Transmitter (UART)
- In serial communications, the UART takes bytes of data and transmits the individual bits sequentially. Adds Start, Stop and sometimes Parity bits before and after the transmitted word.
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- Universal Serial Bus (USB)
- A serial bus gradually replacing RS232 on PCs because of its higher speed.
Standard interface for most computers.
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- Unshielded
- Inductive sensor in which the coil is sensitive to
surrounding metal. For a given coil size, an unshielded
design has a longer sensing distance than a shielded one.
Note, when mounting an unshielded sensor in metal, there
must be a minimum space of one housing diameter (D)
surrounding the sensor head.
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- Unshielded Sensor
- A sensor with limited side and front sensing capabilities.
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- Upscale Break Protection
- A form of break detection for burned-out thermocouples.
Signals the operator that the thermocouple has burned out.
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- Usable Sensing Distance
- Sensing distance after temperature range tolerance and manufacturer's tolerance are taken into account.
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