OPERATING THE ULTRASONIC COMPUTER
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Manual USZ 08 · EN05 · 2015-06
24
Special information: "Parameters for the volume at measurement conditions in
conjunction with ultrasonic flowmeters"
DZU: ERZ 2000 with USE 09-C ultrasonic flowmeter control unit
If you choose this mode, the
FH ultrasonic flowmeter diagnosis
function is of importance. Here
the following information will be shown:
The average velocity of sound measured, indication of the unit, gas velocities of paths 1 to 6,
velocities of sound of paths 1 to 6, AGC (automatic gain control) levels for upstream and
downstream directions, measurement qualities 1 to 6 (= indication of valid measurements in
percent), alarm statuses, and the representation of messages of the USE 09-C.
Functions from the operating modes with pulse input continue to be active and are used
appropriately. These functions include the following:
Starting up and shutting down a plant:
Start-up is trouble-free if qm passes the range from the creeping quantity limit to the lower alarm
limit during start-up and slow-down. An alarm is generated if qm is still below the alarm limit and
above the creeping quantity limit after the start-up or slow-down time has been exceeded. An alarm
is defined as going when the lower alarm limit is passed (when the plant is started up) or when the
creeping quantity limit is passed (when the plant is shut down).
Start-up/slow-down time:
There is a separate "Start-up/Slow-down" chapter to be found under the <9> Meter key. Here you
can see the momentary state, the current start-up and slow-down times and the parameters for the
start-up and slow-down times.
Start-up and slow-down times are parameters for the time monitoring of the lower flow rate limit
qmmin. The qmmin alarm is not triggered until one of these times has elapsed. These parameters
are important for the start-up and slow-down phases.
Creeping quantity limit:
The Vm and Vb totalizer readings are not increased as long as the flow rate at measurement
conditions is below the creeping quantity limit.
Creeping quantity mode:
There are the two following options:
Do not use ("discard") the creeping quantities occurred.
Use the creeping quantities occurred and add ("accumulate") them to normal quantities.
USZ effect of fault:
It is shown whether USZ protocol errors (DZU protocol) are signalled as an alarm or warning or
whether they are not signalled. This depends on the operating mode selected.
