6.2.4
Flow range and meter size
Flow rate (min. flow to max. flow) which the flowmeter will be able to measure depends on the primary data
(3.1.x functions) and application data (3.5.x functions). thus, the flow range specified under the
Fct. 1.1.2 MAX.
FLOW
and
Fct. 1.1.3 MIN. FLOW
must be within the measuring range.
Flow range for any given application is determined by sizing of the meter for that application.
Refer Sect. 6.1
Fct. 4.5
for details on how the application is sized.
The frequency output range value, if programmed in PULSE/time units, directly corresponds to max flow. If flow
rate exceeds max flow an error condition
HIGH FLOW
is generated which may affect current output depending
on programming of
Fct. 1.3.2 RANGE I
. When the flow rate falls below the min. flow an error condition
LOW
FLOW
is generated. Vortex sensor signal is weak at this condition and if flow rate reduces further, vortex signal
related errors such as
CHECK INST., LOW SIGNAL
will occur.
6.2.5
Primary information
Primary data gives VFM 5090(I) the basic information about the vortex primary sensor. Use
Fct. 3.1.1
NOMINAL.DIA
for specification of the nominal DN/ANSI size and
Fct. 3.1.2 K-FACTOR
for the calibration
factor of the primary.
Depending on whether the primary has temperature & pressure sensors, settings need be done in
Fct. 3.6.1 T-
SENSOR
and in
Fct. 3.6.2 P-SENSOR.
These sensors enable VFM 5090(I) to provide online
T
and/or
P
compensation.
6.2.6 Application
information
This is the data of process medium, its operating conditions and physical properties. It consists of :
- process medium
Fct. 3.5.1 FLUID
&
Fct. 3.5.2 MEDIUM
- operating temperature and pressure conditions. Refer
Fct. 3.5.6 TEMP. OPR
and
Fct. 3.5.7 PRES. OPR.
-
density of medium at operating conditions. Required only if software within instrument does not support the
medium (
Fct. 3.5.2
is selected as -
NONE
-)
Refer
Fct. 3.5.8 DENS.OPR.
-
normal or reference P & T values required for normalized flow measurements only (depending on
Fct.
1.1.1
).
Usual values are temp.norm = 0 or 20 Deg. C and pres.norm = 1 atm. Refer
Fct. 3.5.9
TEMP.NORM
and
Fct. 3.5.10 PRES.NORM.
-
density at normal conditions. Required only for normalize volumetric flow and if software within instrument
does not support the medium (
Fct. 3.5.2
is selected as -
NONE
-)
Refer
Fct. 3.5.11 DENS.NORM.
-
Refer also to
Fct. 3.5.3 SAT.P/T
which is applicable to saturated steam only.
Not all of the above data need be given for any given application. Only relevant functions appear during actual
programming.
6.2.7
Internal Electronic Totalizer
-
The internal electronic totalizer counts volume, normalized- volume or mass. Totalizer value is saved in the
non-volatile memory upon power failure. Totalizer can be displayed in the unit desired as per the
programming of
Fct. 1.2.2 TOTAL.UNITS.
Totalizers counting is interrupted for the duration of power
failure. Counting may optionally be stopped and thereafter restarted by the use of
Fct. 3.2.6 TOT. ON/OFF.
-
Resetting [to 0] or Setting of the totalizer is possible by using
Fct. 3.2.5 TOT. VALUE.
If the meter is HEAT METER energy totalizer is provided to store thermal energy.
Refer functions
3.8.3 E.TOT.Val
and
Fct. 3.8.4 E.TOT.ON/OFF.
If the meter is
NET HEAT METER
,
one more energy totalizer is provided to store net thermal energy. Refer
functions
3.8.8 NT. EN. TOT. VAL
and
3.8.9 NE . TOT. ON/OFF
.
But in this case, only two totalizer out
of three (flow, power & net power) can be enabled at a time and not three.
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