6.4 Checking the measuring range (span)
By default, the device has been calibrated
with a linear characteristic based on the up-
per measuring range value of the dp cell.
By later entering the tank and gas data, the
device adopts the tank characteristic; based
on the gas data for the activated type of gas,
the device calculates values for the display
and output signal (4 to 20 mA) that are pro-
portional to the tank content.
In the same way, the differential pressure meter
calculates the max. possible differential pres-
sure
Δ
p100 in
mbar
for the type of gas and the
predefined reference height (total height or
gauge pipe).
At
Δ
p100, the output signal must be 20 mA.
To check the span, connect the differential
pressure meter as illustrated in Fig. 5.
Note!
When checking the span, it is recommend-
able to activate the gas with the highest den-
sity.
The values for gases with a lower density are
calibrated during this process as well.
24
EB 9527-3 EN
Adjustment
0
20
40
60
80
100
%
m
3
x1000
– +
Off
.
~
–
+
–
+
Fig. 8 · Test arrangement
Supply pressure
reducing station with
oil filter and test
pressure gauge
Precision regulator with Class 0.1 pressure gauge
Only use oil-free air or
other gases, e.g. N
2
.
Network
Supply unit
mA display
Test pressure
A
B
Warning!
For devices in
oxygen service
, make absolutely sure that the test medium is
free of oil and grease
.
Summary of Contents for Media 6
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