Filter
Top Products
Technical Guide
DAN-LIQ-Turbine Meter-TG-0807
August 2007
Page 1
+0.15%
–0.15%
+0.02%
–0.02%
TURBINE METER PARAMETERS
These ve terms are the most widely discussed parameters of turbine meter applications.
Linearity is the measure of variation in signal output across the nominal ow range of the meter. The turbine
meter will have a nominal K-factor (number of pulses output for a given volume measured) and this value varies
across the ow range of the meter. Linearity is a measure of the variance of actual output from the average
K-factor. With modern electronics, linearization of the meter registration is possible within a ow computer, and
thus further improvements in measurement accuracy is possible.
Repeatability is the ability of a meter to indicate the same reading each time the same ow conditions exist.
Turbine meters exhibit excellent repeatability and, for many control applications, this is the most important
parameter to be considered.
Accuracy is a measure of how close to true or actual ow the instrument indication may be. It is generally
expressed as a percent of true volume for a specic ow range. This is a “worst case” rating. Accuracy at a
particular ow rate may be an order of magnitude better than “rated ow range accuracy.”
Resolution is a measure of the smallest increment of total ow that can be individually recognized, normally
dened by a single pulse. Turbine meters have an inherently high resolution.
Range is the ratio of maximum ow to minimum ow over which the specied linearity will be maintained. Normal
range (or “turn-down”) is given as 10:1, although this may be exceeded in many cases, depending on meter size
and required linearity.
Figure 1 - Flow Ranges