Model 2000 Flow Computer Instruction Manual
2.0 GENERAL DESCRIPTION
Model 2000 issue 21 Page No
32
Water Mass and Volume percent flow rate equations
19)
100
qM
qM
qM%
L
W
W
×=
20)
100
qN
qN
qN%
L
W
W
×=
21)
100
qG
qG
qG%
L
W
W
×=
Where
qML : Mass flow rate Liquid in kg/hr Measured
qGL : Volume flow rate at line conditions in m3/hr Equation 1)
qNL : Volume flow rate at base conditions in m3/hr Equation 2)
qMW : Mass flow rate Water in kg/hr Equation 16)
qNW : Volume flow rate Water at base conditions in m3/hr Equation 17)
qGW : Volume flow rate Water at line conditions in m3/hr Equation 18)
%qMW : Mass flow rate Water in % of Total Equation 19)
%qNW : Normal Volume flow rate Water in % of Total Equation 20)
%qGW : Gross Volume flow rate Water in % of Total Equation 21)
2.4.5. PRESSURE AND TEMPERATURE INPUTS
2.4.5.1. PRESSURE UNITS
The Units of pressure used in the Model 2000 can be set to be either bar, Kpa, Kg/cm2 or psi in either absolute or gauge
form. In the case of analogue transmitters it is assumed that the 4-20mA current value is calibrated in the required units.
However, in the case of HART transmitters the units value is read from the transmitter and compared against the value
selected, if the value read does not agree with the value selected an accountable Unit alarm is raised. If pressure in absolute
units is selected then all pressure values must be entered and are displayed in absolute units. If pressure in gauge units is
selected then all pressure values must be entered and are displayed in gauge units with the following exceptions:-
Pb Pressure base
Patmos Mean atmospheric pressure
Pused Actual pressure used in all calculations
All of which must be entered and are displayed in absolute units.
2.4.5.2. TEMPERATURE UNITS
The Units of Temperature used in the Model 2000 can be set to be either °C or °F. In the case of analogue transmitters it is
assumed that the 4-20mA current value is calibrated in the required units. However, in the case of HART transmitters the
units value is read from the transmitter and compared against the value selected, if the value read does not agree with the
value selected an accountable Unit alarm is raised.
2.4.5.3. HART TRANSMITTER PRESSURE AND TEMPERATURE INPUTS
The Model 2000 is designed to be used with using the HART communications protocol. Typical transmitters are the
Rosemount Model 3051C Pressure Transmitter and a Rosemount Model 3044/3144 Temperature Transmitter. All
communication with the transmitters is done digitally and the analogue signals from the transmitters is set to the minimum
value and therefore cannot be used for monitoring purposes.
WARNING:- If the transmitters are connected in parallel as a multidrop system and each transmitter must have a different
address.
It is essential that the transmitters have their addresses programmed before they are connected to the Model 2000 Flow
Computer. With Rosemount transmitters the Rosemount Smart Family Interface Model 268 is used for this purpose. It is
recommended that the pressure transmitter be programmed with a short address of 01 and the temperature transmitter with
a short address of 02. Refer to the Rosemount operating manuals for the programming procedures. The Model 2000 can
communicate to HART transmitters acting as a single master, or as a slave. If the Model 2000 is configured to perform as a
slave then the HART transmitters must be configured to operate in burst mode.
WARNING:- If the transmitters are connected in burst mode, only one transmitter is permitted per loop.
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