Formula for Percentage to Process Variable Conversion

Calculate the equivalent Process Variable for any given percentage of signal ( 0 to 100%). We need Transmitter Span, Lower Range Value and Upper Range Value.

Percentage to Process Variable Conversion

Formula:

Process Variable = Span(X/100) +LRV

Span = (URV) – (LRV)

Where

X is Percentage of signal
URV is Upper Range of value
LRV is Lower range of value

Example: 

A pressure gauge is ranged -1 to 1 bar; calculate the Measured Variable for 40 % of signal

Span = (URV) – (LRV) = 2 Bar

Process Variable = Span(X/100) +LRV

Process Variable = (2)(40/100)+(-1)

Process Variable = -0.2 Bar

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