HYDAC HMG 3010 - Manual (Page 23)

HMG 3010 Page 23
Edition 11/2011 - V04 R01 Part No.: 669855
When doing this, identify which pressure
transmitter has been connected to channel A
and which to channel B, since the pressure
transmitters must be re-connected in the
same way later when taking measurements.
Connect the pressure transmitter
hydraulically so that the two instruments are
subjected to the same pressure. The ideal
for recording curves is connecting to a test
rig on which you can increase the pressure
slowly from 0 bar to the full measurement
range of the pressure transmitter and back
again.
However, the minimum requirement is to
record the curves/measured values in the
pressure range in which the differential
measurement is to take place later.
In the example above (to measure the filter
contamination level) both pressure
transmitters might be fitted to the inlet side of
the filter, e.g. using T-fittings and then, with
the machine running, the curve could be re-
corded.
When these pre-conditions are in place,
select Record characteristic curve. This
brings up a display showing 0 to 100% of the
whole measurement range. If you increase
the pressure you will see from the blue bar
that measured values are being recorded in
this pressure range.
If the measured values remain under the red
line, this means that not enough values have
been recorded in this range. To achieve
maximum accuracy for differential
measurement, the recorded measured val-
ues should at least be in the area between
the red and the green line. After this, select
Stop recording and you can quit the menu.
The curve is now automatically taken into
account for the differential measurement
using these two pressure transmitters.