Model 2000 Flow Computer Instruction Manual
2.0 GENERAL DESCRIPTION
Model 2000 issue 21 Page No
51
2.6.3. TEMPERATURE ALARM
A separate non accountable temperature alarm tempN alrm can occur if all of the following conditions occur:-
1) The temperature is below t-alarm and
2) The uncorrected flow rate is above the value of Lo q. and
3) The temperature has been below t-alarm for a programmable time.
NOTE In all cases above the character N will refer to the stream number 1, 2 or 3.
2.6.4. FAULTS
The Model 2000 Flow Computer provides continuous self checking during operation. In normal operation the self checking
routine tests all the memory components for data corruption. A watchdog circuit is also provided to detect failure of critical
components such as the processor. Faults will be indicated for each user board position that contains a board that is either
faulty i.e. non functioning or is a critical board but is missing or is the wrong type of board. All faults will cause the Model
2000 to halt flow calculation and to wait for the defective board to be rectified. When a fault occurs the fault LED is
illuminated and the fault identification is shown on the alarm pages of the LCD display. The following are the types of fault
that will be indicated:-
1) Faulty or missing Input board in user position X. Fault ipX
2) Faulty or missing Output board in user position X. Fault opX
3) Faulty or missing Communication board in user position X. Fault comX
4) Faulty or missing Network board in user position X. Fault netX
5) Wrong board type in user position X. Fault brdX
6) No or incomplete data for operation Fault data
7) Real Time Clock Fault or failure Fault rtc
NOTE In all cases above the character X will refer to the user slot position 1, 2, 3, 4 or 5 (See Figure 2 for slot position
details).
2.6.5. WARNINGS
Warnings will be indicated for each user board position that contains a board that is a non-critical board and is missing or is
the wrong type of board. All warnings will not stop the Model 2000 from calculating flow values. Additionally warnings will be
indicated when any of the pulse outputs are in an over range state. The following are the types of warning that will be
indicated:-
1) Missing Input board in user position X. Warn ipX
2) Missing Output board in user position X. Warn opX
3) Missing Comms. board in user position X. Warn comX
4) Wrong board type in user position X. Warn brdX
5) Pulse Output M on O/P Bd. in position X is Over range opM brdX
6) Model 2000 is set to be in Maintenance mode Err Maint.
7) Model 2000 is set to be in Proving mode proving
8) Model 2000 analogue input calibration is set to Default CalDefault
9) Serial Port Handshaking line CTS pending timeout. Warn ctsX.Y
10) A Divide by zero has occurred Div zero
NOTE In all cases above the character X will refer to the user slot position 1, 2, 3, 4 or 5 (See Figure 2 for details).
The character Y will refer to the communication port 1 is the upper port and 2 is the lower port
The character M will refer to the Digital output 1 to 12.
2.6.6. HIGH AND LOW FLOW ALARMS
A high flow alarm is given if the uncorrected flow rate (or d.p. in the case of orifice plate operation) exceeds the value entered
in memory for Hi q for more than 1 minute. A low flow alarm is given if the uncorrected flow rate (or d.p. in the case of orifice
plate operation) falls below the value entered for Lo q. Both Hi q and Lo q are entered as a % of maximum line flow (Qmax).
When an alarm occurs the Hi/Lo flow LED (Yellow) is illuminated on the front panel, a low or high flow identification is shown
on the alarm pages of the LCD display. A Hi q alarm is defined as an accountable alarm and Lo q as a non-accountable
alarm.
2.6.7. CLEARING OF ALARMS
Alarms can always be cleared if the flow computer is operating in open or partially secure modes. The configuration option
“Clear alarms when fully secure” determines if the alarms can be cleared in fully secure mode.
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