Model 2000 Flow Computer Instruction Manual
2.0 GENERAL DESCRIPTION
Model 2000 issue 21 Page No
29
measurements are derived from the mass measurement these will also be corrected. The value entered into the %Qmax n
data location is in % of maximum flow (Q max.) and the value entered in the corresponding %Er.rd n location is the % error
of reading.
%Er.rd n = the % error in reading at %Qmax n flow rate. n is an integer between 0 and 5
The lowest value of flow in this case nearest to zero flow must be entered at the position n = 0. The rest of the data points
must be entered in ascending value of Q up to the top point. If it is required to enter less than the maximum 5 points then any
unused data positions must be set to invalid data by entering a – sign with no numbers.
2.4.3.3. WET GAS FLOW MEASUREMENT
2.4.3.3.1. WET GAS FLOW MEASUREMENT 1
When operating as a Wet Gas Flow Computer the Model 2000 will operate using Venturi tube calculations as defined in
paragraph 2.5.3 above. In addition Wet gas corrections will be applied to the Venturi mass flow measurement from a
selected list of options as follows:-.
Dickinson/Jamieson correlation
Steven correlation
Chisholm correlation
De Leeuw correlation
Homogeneous (Measured Density Method)
2.4.3.3.2. WET GAS FLOW MEASUREMENT 2
As an alternative when operating as a Wet Gas Flow Computer the Model 2000 can operate using Venturi tube calculations
as defined in paragraph 2.5.3 above and in addition use the De Leeuw correlation for Wet gas corrections to the Venturi
mass flow measurement. This method is primarily intended for use with a Rosemount type 3095 Mass Flow transmitter,
which provides the Model 2000 flow computer with measurement data for Differential Pressure, Static Pressure and
Temperature these values are input into the Model 2000 Flow Computer by means of a Hart connection loop to the Model
3095 transmitter, all three values are read in at one time.
WARNING:- The transmitters should only be connected individually on a connection loop system and each transmitter must
have a different address.
It is essential that the transmitters have their addresses programmed and the burst mode operation turned off before they are
connected to the Model 2000 Flow Computer.
For Rosemount Transmitters the Rosemount Smart Family Interface Model 268 is used to programme the transmitter. Refer
to the Rosemount operating manuals for the programming procedures.
To interface with the hazardous area where intrinsically safe transmitters are used a digital safety barrier must be used a
typical barrier is a Measurement Technology Ltd barrier Model MTL3046B or MTL 5042.
2.4.4. CORIOLIS METER
The meter used is a flow transmitter PP-FT-1352 (Micro motion model RFT 9739 it should be equipped with a modbus serial
output and a frequency/pulse output representing the mass flow. The FC2000 coriolis flow computer shall receive the flow
information using the serial output from the flow transmitter as a source of measured flow. This serial link shall be connected
directly to the flow computer which will acquire all available flow, process and diagnostic data. The frequency/pulse output of
the Flow Transmitter representing the mass flow rate shall be connected directly to the flow computer as the primary source
of measured flow and for use as an integrity check against the serial data. A deviation alarm shall be raised when the flow
rates differ by more than an operator entered limit.
2.4.4.1. CORIOLIS METER PULSE OUTPUT
If the M2000 is configured to accept coriolis meter pulse inputs then these will be of the form of a periodic input signal with
the following parameters.
Current input: 10mA.
Frequency range: Up to 5kHz.
The calculation of total flow continues down to zero frequency as input pulse counting techniques are used.
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