Application Example - VEGA VEGAMET 381 Betriebsanleitung

Damping
To suppress fluctuations in the measured value
display, e.g. caused by an agitated product sur-
face, an integration time can be set. This time can
be between 0 and 250 seconds. Remember that
the reaction time of the entire measurement will
then be longer and the sensor will react to
measured value changes with a delay. In general, a
period of a few seconds is sufficient to smooth the
measured value display.
à
Now select position [9] on the function switch,
enter the requested value and save your
settings
Current output 0/4 ... 20 mA
The characteristics of the current output can be
switched over from 4 ... 20 mA to 0 ... 20 mA.
à
Now select position [8] on the function switch,
adjust the requested characteristics curve and
save your settings
Simulation
To check if the settings ofVEGAMET 381 are
correct, the simulation mode can be used. Any
individual measured value can be simulated and e.
g. the correct behaviour of the relays and the
connected instruments can be checked.
Switching over between the functions "OPERATE"
and "Simulation" is done by pushing the [+/-] keys
for at least 3 seconds. In the simulation mode, the
set value flashes on the display. The simulation can
be switched off by pushing both keys again for
approx. 3 seconds. If no key is pushed, the display
switches automatically over to "OPERATE" after
approx. 60 minutes and the simulation is termi-
nated.
à
To start simulation, push the [ +/-] keys
simultaneously until the displayed value starts
flashing (approx. 3 seconds). By pushing either
of the [ +/-] keys, you can set the requested
simulation value and carry out your check.
Reset
With a reset, all values set by the user will be
lost and are reset to factory settings.
à
Interrupt the power supply of VEGAMET 381.
Push the [+/-] keys simultaneously and hold
them while you switch on the power supply.
VEGAMET 381
Setup with the integrated indicating and adjustment unit
The display shows "RES" and the default
settings will be restored. These are the
following:
Relay switch on points: 10 %
l
Relay switch off points: 100 %
l
Decimal point: 888.8
l
Display min.: 0
l
Display max.: 100.0
l
Integration time: 0 s
l
Offset correction: 0
l
Current output: 4 ... 20 mA
l
Min. adjustment: 0 % or 4 mA
l
Max. adjustment: 100 % or 20 mA
l

6.3 Application example

An upright cylindrical (linear) tank has a volume
l
of 2700 l
The max. filling volume is 2650 l, the min. filling
l
volume 50 l
The level sensor in the vessel is a pressure
l
transmitter (passive), outputting a standardised
4 ... 20 mA signal
For further processing, an additional 4 ... 20 mA
l
output signal is required
The full and empty adjustment was carried out
l
directly in the sensor. The following values are
outputted:
Max. volume (display max.) 20 mA = 2650 l
-
Min. volume (display min.) 4 mA = 50 l
-
Relay 1 should switch on an emptying pump at
l
a level of 90 % and switch off the pump at a
level of 10 %
General procedure
Select the following functions with the rotary
1
switch.
Push one of the two [+/-] adjustment keys, the
2
digital indication flashes (if the rotary switch is
set to "OPERATE", the [+/-] keys are inoper-
able)
Adjust the requested value with the [+/-] keys. If
3
you hold the key pushed, the digital indication
changes the value more quickly.
Save your settings by pushing the [+/-] keys
4
simultaneously
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