Accubar SDI-12 Barometric Pressure Sensor Operations & Maintenance Manual Rev-B 30 Nov 2017
pg. 43
E xa mple T e mpe ra ture e rror of a C ompe titor's 0 .5 mB "A ccura te " Ba rome te r
-4
-3
-2
-1
0
1
2
3
4
-40
-30
-20
-10
0
10
20
30
40
50
60
Temperature in degrees C
Hysteresis - This is a measure of deviation in the output when passing through an input point from two
different directions. If a pressure transducer has zero pressure applied, then 10 PSI, then 22 PSI, then 10
PSI, the difference between the two 10 PSI readings would be a measure of the pressure hysteresis of
the transducer. Pressure transducers can also have temperature hysteresis errors. Sometimes
hysteresis is lumped in with other non-repeatability errors.
ACCURACY
- Accuracy is a measure of how closely the sensor's output matches the "true" value of the
parameter being sensed.
PRECISION
- Precision is a measure of the repeatability of the sensor. It will most always be better than
the accuracy of the sensor.
RESOLUTION
- The resolution of a sensor is the smallest change in the input that is reflected in the
output. For digital sensors it also refers to the smallest increment of the output. This may be greater
than or less than the sensor's resolution with respect to its input. Greater resolution does not imply
greater accuracy. Resolution and Accuracy are two independent variables. The advantage of resolution
in excess of accuracy is that changes in the input parameter can be detected and tracked.
