Application Example - Vega MET 381 EX Mise En Service

6 Setup with the integrated display and adjustment unit
→
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.
→
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 Ex 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 "OPERA-
TE" 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 terminated.
→
To start simulation, push the [ +/-] keys si-
multaneously 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.
→
Interrupt the power supply of VEGAMET
381 Ex. Push the [+/-] keys simultaneously
and hold them while you switch on the
power supply. The display shows "RES" and
the default settings will be restored. These
are the following:
•
Relay switch on points: 10 %
•
Relay switch off points: 100 %
•
Decimal point: 888.8
•
Display min.: 0
•
Display max.: 100.0
•
Integration time: 0 s
•
Offset correction: 0
•
Current output: 4 ... 20 mA
•
Min. adjustment: 0 % or 4 mA
•
Max. adjustment: 100 % or 20 mA
28
6.3

Application example

•
An upright cylindrical (linear) tank has a
volume of 2700 l
•
The max. filling volume is 2650 l, the min.
filling volume 50 l
•
The level sensor in the vessel is a pressure
transmitter (passive), outputting a standar-
dised 4 ... 20 mA signal
•
For further processing, an additional
4 ... 20 mA output signal is required
•
The full and empty adjustment was carried
out 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 a level of 90 % and switch off the pump at
a level of 10 %
General procedure
1. Select the following functions with the rotary
switch.
2. Push one of the two [+/-] adjustment keys,
the digital indication flashes (if the rotary
switch is set to "OPERATE", the [+/-] keys
are inoperable)
3. Adjust the requested value with the [+/-]
keys. If you hold the key pushed, the digital
indication changes the value more quickly.
4. Save your settings by pushing the [+/-] keys
simultaneously
Current output
1. Set the function switch to position [8]. Select
with the [+/-] keys the measured value
output 4 ... 20 mA or 0 ... 20 mA. For this
example, choose 4 - 20.
The displayed numbers have the following
meanings:
•
0 - 20 = 0 ... 20 mA
•
4 - 20 = 4 ... 20 mA
2. Save the value by pushing [+/-] simultane-
ously
VEGAMET 381 Ex requires for scaling of the
indication, the adjustment of the filling quantities
for 0 % and 100 %. The vessel must neither be
filled nor emptied.
Scaled indication at 0 %
1. Set the function switch to position [7] (dis-
play min.)
VEGAMET 381 Ex • 4 ... 20 mA signal conditioning instrument