Model 2000 Flow Computer Instruction Manual
2.0 GENERAL DESCRIPTION
Model 2000 issue 21 Page No
43
This function uses the Status input to replace Mode switch 2 when operating as a Security Switch On/Off. When this
option is selected the internal Mode Switch 2 has no function.
• Oil Status
This function uses the Status input as a switch contact input, in conjunction with a turbine meter fitted with a Lubrication
Oil level indication output.
• Hold Counters
This function uses the Status input as a switch contact input to provide the Hold Counters function. The Model 2000 can
be set to provide copies of the Main and Main Alarm Totals that can be stopped or Held by operating this function.
These Totals in a Held position must be enabled in order to be viewed under the Main Menu item Totals.
• Set Time
When a change of state from a logic 0 to a logic 1 is detected on this input then the contents of the Preset Time
registers Preset hour, Preset minute and Preset seconds is copied to the current time for the M2000 clock.
• Can Alarm
When a change of state from a logic 0 to a logic 1 is detected on this input then this indicates that the Grab Sampler can
level alarm has been set. This will be either for Liquid Grab Sampler 1 or 2 which ever input has been configured for this
function.
Under normal circumstances the polarity of the status inputs is as follows:-
Input open (logic 1) indicates forward +ve or normal flow. (Also for a single flow direction)
Input closed (logic 0) indicates reverse or –ve flow.
It is possible to reverse the polarity of the input by selecting the tick box Invert adjacent to each input.
2.4.11. STATION PRESSURE AND TEMPERATURE INPUTS
The Station Pressure and Temperature inputs 1 and 2 are general purpose inputs for Pressure and Temperature they are
available on all M2000 types and are intended for indication purposes only. They do not form any part of the flow
calculations. Station Pressure and Temperature values can be displayed, printed etc. in the same way that all variable items
can be.
2.4.11.1. STATION PRESSURE UNITS
The Units of station 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 station pressure in
absolute units is selected then all station pressure values must be entered and are displayed in absolute units. If station
pressure in gauge units is selected then all station pressure values must be entered and are displayed in gauge units except
Patmos Mean atmospheric pressure, which must be entered and is displayed in absolute units.
2.4.11.2. STATION TEMPERATURE UNITS
The Units of Station 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.
2.4.11.3. HART TRANSMITTER STATION 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:- 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 and the burst mode operation turned off 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.
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