are sampled. Each RTD sensor type has expected current based on the sensor type. Ifthe measured offset current deviates from the reference current more than 20%, thesample is discarded and the output is set to invalid. The invalid measure statusdeactivates as soon as the measured input signal is within the measurement offset.3.12.2.6 CalibrationRTD and mA inputs are calibrated at the factory. The calibration circuitry monitorsthe RTD channels continuously and reports a circuitry break of any channel.3.12.2.7 Limit value supervisionThe limit value supervision function indicates whether the measured value ofAI_INST# exceeds or falls below the set limits. All the measuring channels have anindividual limit value supervision function. The measured value contains thecorresponding range information AI_RANGE# and has a value in the range of 0 to 4:• 0: “normal”• 1: “high”• 2: “low”• 3: “high-high”• 4: “low-low”The range information changes and the new values are reported.AI_RANGE#=1AI_RANGE#=3AI_RANGE#=0HysteresisVal high high limitVal high limitVal low limitVal low low limitAI_RANGE#=2AI_RANGE#=4YtAI_RANGE#=0Value ReportedValue maximumValue minimumOut of RangeGUID-6A6033E6-22C8-415D-AABD-D0556D38C986 V1 ENFigure 34: Limit value supervision for RTD (X130)The range information of “High-high limit” and “Low-low limit” is combined from allmeasurement channels to the Boolean ALARM output. The range information of“High limit” and “Low limit” is combined from all measurement channels to theBoolean WARNING output.Section 3 1MRS758755 ABasic functions90 REC615 and RER615Technical Manual
