SFAM
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Festo – SFAM – 1103a English
The maximum error results from the largest full-scale measurement value (in the example
FS = 1000 l/min). According to the specification the error is indicated with ±3%FS.
The maximum error is calculated as follows:
±3%FS = ±3% x 1000 l/min =±3/100 x 1000 l/min = ±30.00 l/min
If a measurement value of 600 l/min is displayed, the maximum range error is calculated as follows:
±30 l/min × (600 l/min)/(1000 l/min)= ±18 l/min
With a display of 600 l/min at the sensor, because of the range error the actual flow through the sensor
values can have values in the range 582 … 618 l/min.
Along with the range error, the zero point error must still be taken into account.
b) Zero point error
A zero point error in the measurement signal affects every point of the characteristic curve equally, that
means it is independent of the measurement value considered (
Fig. 13: ).
x
y
z
x = measurement variable (flow)
y = measurement value (display)
z = display value error sought
Fig. 13: Zero point error
According to the specification the error is indicated with ±0.3%FS. In our case FS = 1000 l/min.
The error is calculated as follows:
±0.3%FS = ±0.3/100 x 1000 l/min = ±3 l/min
With a display of 600 l/min at the sensor, because of the zero point error the actual flow through the
sensor values can have values in the range 597 … 603 l/min.
