KROHNE VFM 5090 EN - Manual (Page 46)

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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