PLC/ DCS Analog Input Conversin

We Will Understand this Formula by a Simple Calculation


A Temperature Transmitter Range is  0 to 50 c is connected to an PLC analig input card . the PLC analog input Card row count Starting from 7250 for 4 mA ANF 33208 For 20 mA.  A PLC reading is 17975 row count and Calculate Transmitter Actual Reading.

We Know That

Given

Data @4Ma  = 7250

Data @20 Ma  = 33208

Range of Transmitter = 0 to 50 c

Resolution :- 0.1

Data Offset = 7250

Data Span = 33208 – 7250            

                = 25958

EU Offset = 0 x 10 = 0

EU Span = (60-0) x10

                = 600

Data = 17975

EU = ((EUSpan x (DATA – DataOffset))/DataSpan) + EUOffset

EU= ((600 X (17975- 7250)) / 25958 + 0

EU= ((600 X (10725)) /25958

EU = (6435000)/25958

EU= 247

Process Value = EU/ Factor

Process Value = 247/10= 24.7 c