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A/D(Analog to Digital) Conversion of continuously varying (analog) voltage levels to discrete binary-numbered (digital) values (e.g., a load cell output can be fed through an A/D convertor to produce a continuous stream of digitised information and sent to a digital indicator).
ACCURACYPrecision in the measurement of quantities and in the statement of physical characteristics. Accuracy is typically expressed in terms of error as a percentage of the specified value (e.g., 10 volts ± 1%), as a percentage of a range (e.g., 2% of full scale), as parts (e.g., 100 parts per million) or with absolute tolerances (e.g., 6.7kg ± 0.1kg).
ANALOG SIGNALA signal that continuously represents a variable or condition.
APERTUREThe total range (in percentage) of full scale capacity over which a digital weight indicator's "Automatic Zero Maintenance" (AZM) and "Push-button Auto Zero" (PAZ) functions will operate; Handbook 44 maximum is ±2% of full scale.
APPROVEDAcceptable to the authority having jurisdiction over the area for in which a system or equipment will be used.
AZM (Automatic Zero Maintenance) An electronic means of providing "true zero" at all times on a digital scale. AZM compensates for such conditions as indicator or load cell drift or debris on a scale platform by electronically tracking out minor variations around zero; also called "zero tracking".
CALIBRATETo ascertain that the output of a device properly corresponds to the information it is measuring, receiving or transmitting. This might involve the location of scale graduations, adjustment to bring the output within specified tolerance or ascertaining the error by comparing the output to a reference standard.
CALIBRATIONThe process of adjusting an instrument or compiling a deviation chart so that its reading can be correlated to the actual values being measured.
COMBINED ERROR(Non-linearity and Hysteresis) The maximum deviation from the straight line drawn between the original no-load and rated load outputs expressed as a percentage of the rated output and measured on both increasing and decreasing loads.
DIGITAL AVERAGINGThe ability of a digital indicator to smooth bouncy or erratic readings by taking several readings and averaging them together before sending the signal to the display. Increasing the digital averaging slows the indicator's update rate.
ERRORThe difference between the measured signal value or actual reading and the true (ideal) or desired value.
GRADUATIONA mark on an instrument or vessel indicating degrees or quantity.
HYSTERESISThe maximum difference between scale output readings for the same applied load. One reading is obtained by increasing the load from zero and the other reading is obtained by decreasing the load from rated load. Measurements should be taken as rapidly as possible to minimise creep.
LINEARITYThe closeness to which a curve approximates a straight line or the deviation of an instrument's response from a straight line.
LIVE LOADThe load applied to a scale base which is actually being measured by the weighing system.
LOADThe weight or force applied to the load cell.
LOAD CELLA device which produces an output signal proportional to the applied weight or force. Types of load cells include beam, Shear-beam, compression, tension and single point.
MASSThe quantity of matter in a body.
MILLIVOLT (mV) One thousandth of a volt.
N(Microvolt ( µV) One millionth of a Volt.
nmax (Maximum Number of Scale Divisions) The maximum number of scale divisions for which a product has been approved. The nmax must be greater than or equal to the number of divisions for which the scale will be configured.
NON-LINEARITYSee under Linearity
OVERLOAD RATING SafeThe maximum load, in percent of Rated Capacity, which can be applied without producing a permanent shift in performance characteristics beyond those specified.
OVERLOAD RATING UltimateThe maximum load, in percent of Rated Capacity, which can be applied without producing a structural failure.
PAZ(Push button Auto Zero) Extension of the AZM function of a digital weight indicator through the use of a front panel push-button.
REPEATABILITYThe maximum difference between scale output readings for repeated loadings under identical loading and environmental conditions; the ability of an instrument, system, or method to give identical performance or results in successive instances. It is usually measured as non-repeatability and expressed as in percent of span.
RESOLUTIONThe smallest change in input which produces a detectable change in the output. This is the smallest increment of change that can be detected by a measurement system.
SENSITIVITYThe minimum change in a physical variable to which an instrument can respond; the ratio of the change in output magnitude to the change of the input which causes it after the steady-state has been reached.
SPANThe difference between the highest value and the lowest value.
STABILITYThe ability of an instrument or sensor to maintain a consistent output when a constant input is applied. Steady-state: A characteristic of a condition, such as value, rate, periodicity, or amplitude, exhibiting only negligible change over an arbitrary long period of time.
STRAINThe ratio of the change in length to the initial unstressed reference length of an element under stress.
STRAIN GAUGEA device for detecting the strain that a certain force produces on a body. The gauge consists of one or more fine wires cemented to the surface under test. As the surface becomes strained, the wires stretch or compress, changing their resistance. Several strain gauges are used to make-up a load cell.
TAREThe weight of an empty container or vehicle, or the allowance or deduction from gross weight made on account there of.
TRACEABILITYThe step-by-step transfer process by which the scale calibration can be related back to primary standards.
TRANSDUCERAn element or device which receives information in the form of one quantity and converts it to information in the same or an other quantity or form. For example a load cell converts a strain induced by an applied load into an electrical signal.
WEIGHTThe force or amount of gravitational pull by which an object or body is attracted toward the centre of the earth.
ZERO RETURNThe difference in Zero Balance measured immediately before Rated Load application of specified duration and measured after removal of the load, and when the output has stabilised.
ZERO SHIFTPermanent A permanent change in no-load output.
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