Ashcroft GC52 - Rangeable wet/wet Differential Pressure Transmitter - Manual (Page 19)

19
11.4 Flow Measurement/Square Root Extraction Mode
Square Root Display Mode
Combining the sensing elements (orifice and pitot tube) with this prod-
uct, the mode is used for the display of the momentary flow rate, inte-
grated volume and for analog output corresponding to the momentary
flow rate.
(1) Momentary flow rate
Maximum display span from zero to the maximum momentary flow
rate. The
Momentary flow rate display span depends on the set-
ting of the zero point and span point of the analog output as shown
in (2) analog output. It can display 0 to 105%F.S. of the momentary
flow rate display span. The scaling method can be performed only
by setting the maximum momentary flow rate and then generate
differential pressure using the following square root formula.
Momentary flow rate Dx is expressed by the square root formula
(a), and can be calculated only by measuring the generated differ-
ential pressure Px (percent value over the differential pressure
range).
k =
D
m
00
P
m
100
D
x
= k x
P
x
(%)
100(%)
͌
͌
In addition, the coefficient k is determined by substituting the
maximum momentary flow rate Dm, which is measured from the
formula (a), and the then generated differential pressure Pm into
the formula (b).
• The differential pressure generated during the maximum momen-
tary flow rate can be set in the range of 25 to 100%F.S. of the differ-
ential pressure range.
• The setting range for values of the maximum momentary flow rate
is 0 to 1999. Note: The decimal point can be set arbitrarily.
Setting of max. momentary flow rate and then
generated differential pressure
==> Setting item
ተ, ቱ, ቲ
(a)
(a)