SFAM
Festo – SFAM – 2017-09c English
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Fig. 13
Zero point error
The error is specified at ±0.3 %FS according to specification. 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
Because of the zero point error, with a display of 600 l/min at the sensor, the actual flow rate through
the sensor values can have values in the range 597 … 603 l/min.
c) Total errors under nominal conditions
To the total errors under nominal conditions, the error margin of ±18.00 l/min and zero point of
±3.00 l/min must be added, so that at 600 l/min the following total error results:
600 l/min ±21.00 l/min
With a display of 600 l/min at the sensor, because of the zero point error the actual flow rate through
the sensor values can have values in the range of 579 … 621 l/min.
d) Temperature fault
If the sensor is not operated at nominal conditions (6 bar, 0.6 MPa, 23 °C), e.g. at a pressure of
6 bar/0.6 MPa and a temperature of 40°C, which is outside nominal conditions with regard to
temperature.
In this case, a temperature error must be added to the overall error worked out under nominal
conditions.
According to specification:
–
Temperature coefficients: typ. ±0.1 %FS/K.
As a deviation to the nominal condition, a temperature difference of 17 °C at 40 °C results. The
temperature error range is calculated from the temperature difference and the temperature coefficient
as follows:
