G4 Multi Channel Weighing Instrument. PM/DT/HE Technical Manual

Technical ManualData sheet calibrationData sheet calibration is recommended as first-time calibration for a new installation.In data sheet calibration, values from the transducer data sheets are entered asparameter values, the scale need not be loaded and an accuracy of 0.1 % can beobtained. The accuracy of the G4 Instrument itself is 0.005 % (1-2 years calibrationperiod). It is essential that no external forces influence the scale installation. If fixedsupport points are included in the scale, the load must be evenly distributed ontransducers and fixed supports.Conversion factorIn transducer data sheets, loads are normally not expressed in the measurementunit, selected for the scale. This parameter defines a constant by which a weightvalue, expressed in the measurement unit, should be multiplied to be expressedin the data sheet unit.When using a transducer, calibrated in Newton, in a scale displaying weight valuesin kg, the ‘Conv. factor’ shall be the local gravitation constant in m/s 2 .The default value, 9.80665, is an international mean value for the gravitationconstant (world-wide range 9.78 – 9.83).If the data sheet unit is the same as the measurement unit, the conversion factorparameter should be set to 1.0000.Number of transducersIn weighing applications the load on the scale may be supported by severaltransducers or fixed supports. This parameter defines the total number of transducersand fixed supports in the scale, up to maximum 4.If the scale has more than 4 support points, this parameter should be set to ‘1’and the parameter value for ‘Rated load’ and ‘Rated output’ must be calculated.Rated loadRated load for a transducer is indicated in the data sheet and should be entered as aparameter value, expressed in the unit of the data sheet.NOTE! If the data sheet value is 5 kN, this parameter should be set to 5000 (N).If several transducers are used in a scale, they must all have the same rated load.If the scale has more than 4 support points, ‘Number of transd’ should be set to ‘1’and the value of this parameter should be calculated as:rated load for one transducer, multiplied by the total number of support points.Rated Output 1 (2, 3, 4)Rated output is given in the data sheet for every transducer. Parameters will beavailable for the number of support points specified in ‘Number of transd’.For fixed support points the rated output value is 0.00000 (mV/V).If the scale has more than 4 support points, ‘Number of transd’ should be set to ‘1’and the parameter value for ‘Rated output 1’ should be calculated as:the mean value of rated output for all active transducers.4-4