Siemens PLC Analog Input Scaling The following variables are pertinent to the scaling formula: Ov = scaled output value Iv = analog input value Osh = high limit of the scale for the scaled output value Osl = low limit of the scale for the scaled output value Ish = high limit of the scale for the analog input value Isl = low limit of the scale for the analog input value
The scaling scheme can be diagrammed as follows: The following formula for calculating the scaled value can be derived from the diagram: Ov = [(Osh – Osl) * (Iv -Isl) / (Ish – Isl)] + Osl Which can be rewritten as: Ov = [(Osh -Osl)/(lsh-lsl)/(lsh -lsl)] + Osl