Festo — SFAB-...-PNLK — 2022-08
Technical data
49
Spread error (e.g. ± 3 % FS)
Zero point error
Tab. 30: Spread error and zero point error
Spread error and zero point error
The spread error is proportional to the measured value. At 600 l/min, the spread error is 3% of the
measured value = 18 l/min.
The zero point error is independent of the measured value. It is 0.3% FS = 3 l/min.
Display error under nominal conditions (6 bar, 23 °C):
The display error under nominal conditions is the result of adding the spread and zero point errors.
The actual flow rate is in the range of 600 ± (18+3) l/min = 600 ± 21 l/min.
Display error under deviating nominal conditions (e.g. 8 bar, 40 °C):
Temperature and pressure errors are spread errors. The temperature error at 40 °C is
±0.1% FS/K x 17 K = ±1.7% of the measured value = ±10.2 l/min.
The pressure error at 8 bar is ±0.5% FS/bar x 2 bar = ±1% of the measured value = ±6 l/min.
The error of the display at deviating nominal conditions results from the addition of all error values
(span, zero point, temperature, pressure). The actual flow rate is therefore in the range of 600 ±
(18+3+10.2+6) l/min = 600 ± 37.2 l/min.
