Resources : Technical Support & Advice : Glossary of Terms

ABSOLUTE PRESSURE
The pressure measured relative to zero pressure (ie, vacuum).

ACCELERATION
Acceleration error expressed as percent of SENSITIVITY full scale output per unit acceleration.

AMBIENT TEMPERATURE
The temperature of the medium surrounding the transducer.

AXIAL LOAD
A load applied along the primary axis of the transducer

BI-DIRECTIONAL
A transducer which can be used to monitor both positive and negative changes in the measurand.

BRIDGE
A Wheatstone bridge configuration, which utilises at least one active strain gauge.

CALIBRATION
The comparison of transducer outputs against the outputs of a reference standard.

COMBINED ERROR (repeatability, non-linearity, hysteresis)
Maximum deviation from the best straight line drawn through the zero balance point (best fit through zero). Derived from consecutive applications of both decreasing and increasing load (expressed as a % of the full scale output).

COMMON MODE PRESSURE
See LINE PRESSURE

COMPENSATED TEMPERATURE RANGE
The range of temperature over which a transducer can operate up to full scale and still meet all specifications.

COMPRESSION LOAD CELL
A load cell designed for the measurement of compression forces only.

CREEP
The change in load cell output occurring with time after removal of a load which had been applied for a specific period.

CREEP RECOVERY
The change in no-load output occurring with time after removal of a load which had been applied for a specific period.

CROSS AXIS SENSITIVITY
See TRANSVERSE SENSITIVITY.

DEFLECTION
The physical movement of the transducers sensing element between zero and full scale.

DRIFT
A random change in output under constant load or pressure conditions.

DYNAMIC LOADS 
Are time dependant and act for a small interval of time or change quickly in magnitude or direction e.g. earthquake forces, machinery vibrations, moving vehicles.

ECCENTRIC LOAD
Any load applied parallel to but not concentric with the primary axis.

ENVIRONMENTAL PROTECTION
The conditions under which the transducer may be expected to perform to its specification often given an IP rating.

EXCITATION, ELECTRICAL
The recommended voltage or current applied to the input terminals of the transducer.

EXCITATION. ELECTRICAL MAXIMUM
The voltage or current up to which the transducer can be operated in practical application, and within which the technical data and error specifications are maintained.

FATIGUE RATED
A term used in conjunction with load cells intended for fatigue applications, usually denotes a derating factor to enhance the operational life.

FREQUENCY, NATURAL
The frequency or free (not forced) oscillations of the sensing element of a fully assembled transducer.

FULL SCALE
See RATED CAPACITY

FULL SCALE OUTPUT
The algebraic difference between the minimum output (normally zero) and the rated capacity.

GAUGE PRESSURE
Pressure relative to atmospheric. Represents positive difference between measured pressure and existing atmospheric pressure.

HYSTERESIS
The maximum difference between transducer output readings for the same applied load; one reading obtained by increasing the measurand from zero and the other by decreasing the measurand from rated capacity.

NOTE:-
(a) For load cells primarily intended for weighing applications and pressure transducers normally measured at half full scale output and expressed in percent of full scale.
(b) For load cells primarily intended for force measurements normally measured at zero load after excursion to full scale.

INPUT IMPEDANCE
The resistance measured across the excitation terminals of a transducer at standard temperature, with no load applied, and with the output terminals open-circuited.

INSULATION RESISTANCE
The electrical resistance expressed in ohms measured between any electrical connector pin or lead wire and the transducer body or case. Normally greater than 500Mohms measured at 500VDC.

IP RATINGS
The IP rating system provides a means of classifying the degrees of protection from dust, water and impact afforded by electrical equipment and enclosures. The system is recognised in most European countries.

JUNCTION BOX
An electrical circuit generally used with load cells enabling the connection of two or more transducers in parallel. Can be supplied with balancing components, to adjust the sensitivities of one or more transducers individually.

LINE PRESSURE
The maximum pressure in the vessel or pipe for differential pressure measurement.

LOAD BEAM LOAD CELL
A load cell employing as its primary transduction element a cantilevered beam, in which the strain due to bending is sensed.

LOAD BUTTON
The spherical like shape of the top surface of a load cell where the load is applied. Often supplied as a screwed in accessory.

MEASURAND
A physical measured, quantity/property or condition which is measured.

FREQUENCY
The frequency of free oscillations under no load or no pressure conditions.

NON LINEARITY
The maximum deviation of the calibration curve above and below the best straight line through the data pointed with the best straight line derived by the method of least squares.

OPERATING TEMPERATURE RANGE
The range of temperature over which a transducer can operate up to full scale and still meet all specifications.

OUTPUT IMPEDANCE
The resistance as measured on the output terminals of a transducer at standard temperature, with no measurand applied, and with the excitation terminals open-circuit.

OVERLOAD STOP
A mechanical device designed to prevent over-stressing of the transducers sensing element.

OVERRANGE, SAFE
The maximum pressure or load which may be applied to the transducer without causing a permanent change in the performance specifications.

PEAK HOLD
An electronic device for capturing the peak value of the transitory input of a transducer system.

PRIMARY AXIS
The axis along which a force or load is designed to act.

RATED CAPACITY
The maximum measurand that a transducer is designed to measure within its specification.

RATIONALISED OUTPUT
The maximum difference in output of any number of transducers of the same type and the same range when each is subjected to full scale capacity (expressed as a % of the output at full rated load).

REPEATABILITY
The ability of a transducer to reproduce output readings when the same measurand value is applied to it consecutively, under the same conditions, and in the same direction. Repeatability is expressed as the maximum difference between output readings as a percent or full scale.

SECONDARY CONTAINMENT
The maximum pressure a transducers casing can withstand without leakage in the event of a sensing diaphragm mechanical failure.

SENSITIVITY
The ratio of change in transducer output to change in the value of the measurand.

SHEAR BEAM LOAD CELL
A load cell employing as its primary transduction element a beam in which the shear strain is sensed.

SIDE LOAD
Any load acting 90 degrees to the primary axis at the point of axial load application.

SINGLE POINT LOAD CELL
A load cell whose output is independent of bending moment within qualified limits.

SPAN
The algebraic difference between the limits of the range from zero to full scale.

STANDARD TEST CONDITIONS (OR REFERENCE CONDITIONS)
The environmental conditions under which measurements should be made when measurements under any other condition may result in disagreement between various observers at different times and places. These conditions are as follows:-

Temperature: 23°C ±2°C
Barometric pressure: 950 to 1085 mbar

STRAIN GAUGE
An electrical resistor whose resistance varies with applied mechanical strain.

THERMAL SENSITIVITY REPEATABILITY
The maximum difference between electrical outputs at full range input obtained after cycling the transducer a specified number of times over the rated temperature range. It is expressed as a percentage of full range output per degree C.

THERMAL SENSITIVITY SHIFT
The change in rated output due to a change in ambient temperature. Usually expressed as a percentage change or reading per degree C change in ambient temperature, over the compensated temperature range.

TARE
Amount deducted from gross weight in ascertaining net weight.

TARE OFFSET
An electrical offset applied to a transducer's output to cancel the effect of a tare load.

THERMAL ZERO REPEATABILITY
The maximum difference between electrical outputs at zero applied input obtained after cycling the transducer a specified number of times over the rated temperature range. It is expressed as a percentage of full range output per deg C.

THERMAL ZERO SHIFT
The change in zero balance due to a change in ambient temperature. Usually expressed as a percentage change in full scale output per degree C change in ambient temperature over the compensated temperature range.

TORQUE TRANSDUCER
A transducer whose output is proportional to applied torsional moment about the primary axis.

TRANSDUCER
A device which when acted upon by a physical stimulus produces an electrical output in proportion to that stimulus.

TRANSDUCTION ELEMENT
The electrical portion of a transducer in which the output originates.

TRANSMITTER
A transducer with integral active electronics which can include voltage or current amplifiers and/or integral voltage/current regulation.

TRANSVERSE SENSITIVITY
The sensitivity of a transducer to transverse acceleration or other transverse measurand.

WET/DRY
Describes the operational condition: which must be complied with for the primary and reference sides of a pressure transducer, ie. the reference side must always be maintained in clean, dry, non-corrosive conditions.

WET/WET
As per WET/DRY except that the restrictions the reference side of the transducer are waived.

ZERO BALANCE
The output signal of a transducer at rated excitation and with no measurand applied. usually expressed in percent of full scale.

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