54 VA Master FAM540 METAL CONE VARIABLE AREA FLOWMETER | OI/FAM540-EN REV. E
… 9 Operation
Description of menus and parameters
‘Prog.Output’ Menu
In this menu, the programmable binary output (terminals
41 / 42) is parameterized .
The following settings are available:
Function Description
Pulse output Pulses with the parametrized pulse value (pulses /
unit) are output
Max / Min alarm _ _ The contact is closed in the event of an alarm
Min / Max alarm / _ The contact is opened in the event of an alarm
General alarm _ _ The contact is closed in the event of an alarm
General alarm / _ The contact is opened in the event of an alarm
Note
If the output is parameterized as a general alarm, the error
states and min-max alarms are output cumulatively.
‘Operating mode’ Menu
The device has been calculated and rated for a specific
application.
The device can be adapted to a different, new application using
the operating mode and the associated parameters, such as the
operating density or the standard density of the measuring
medium.
The device uses the new parameters to calculate its new
maximum measuring range end value (Q
max
Medium). The
current position of the float is automatically converted into the
correct flow value. It may be necessary to adapt the Q
max
value.
‘Standard density’ and ‘Operating density’ Menu
Depending on the operating mode, the system requests the
standard density or the operating density of the measuring
medium.
The density of liquids always has to be stated in the operating
condition.
Standard densities for a few selected gases:
Gas Standard density [kg/m3]
Acetylene 1.172
Ammonia 0.771
Argon 1.780
Ethane 1.350
Ethylene 1.260
Butane 2.700
Natural gas 0.828
Carbon dioxide 1.970
Carbon monoxide 1.250
Air 1.290
Methane 0.717
Neon 0.890
Propane 2.020
Propylene 1.915
Oxygen 1.430
Nitrogen 1.250
Hydrogen 0.0899
To convert the standard (normal) density to the operating
density, use the following formula for ideal gases (based on Gay-
Lussac and Boyle-Mariotte):
Standard density (ρ
η
) to operating density (ρ) conversion
ρ = ρ
η
x
1.013 + p
×
273
1.013 273 + T
Legend
ρ Operating density [kg/m3]
ρ
Standard density [kg/m3]
p Operating pressure [bar]
T Operating temperature [°C]
‘Low flow cut off’ Menu
Entry range: 1 to 10 %
The low flow value is needed for the low flow cutoff.
If the measured flow falls below the set value, the measured
value is set to zero, i.e. the current output indicates 4 mA and the
flow count is interrupted.
For variable area flowmeters, this value should be set to 5%
because of the physical conditions.
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