The input scaling can be bypassed by selecting Value unit = "Ohm"when Input mode = "Resistance" is used and by selecting Value unit= "Ampere" when Input mode = "0...20 mA" is used.Example for linear scalingMilli-ampere input is used as tap changer position information. The sensorinformation is from 4 mA to 20 mA that is equivalent to the tap changer positionfrom -36 to 36, respectively.Input maximumInput minimumInput mode”0..20mA”4 mA20 mAValue minimum-36AI_VAL#Value maximum36Value unit”Dimensionless”X130-Input#GUID-85338A5E-3D2F-4031-A598-EA8A525190D3 V1 ENFigure 24: Milli-ampere input scaled to tap changer position information3.11.2.4 Measurement chain supervisionEach input contains functionality to monitor the input measurement chain. Thecircuitry monitors the RTD channels continuously and reports a circuitry break ofany enabled input channel. If the measured input value is outside the limits, minimum/maximum value is shown in the corresponding output. The quality of thecorresponding output is set accordingly to indicate misbehavior in the RTD/mA input.Table 51:Function identification, limits for the RTD/mA inputsInput Limit valueRTD temperature, high > 200 °CRTD temperature, low < -40 °CmA current, high > 23 mAResistance, high > 2000 Ω3.11.2.5 SelfsupervisionEach input sample is validated before it is fed into the filter algorithm. The samplesare validated by measuring an internally set reference current immediately after theinputs are sampled. Each RTD sensor type has expected current based on theSection 3 1YHT530004D05 DBasic functions88 615 seriesTechnical Manual
