BA_078_en_10.01 Level transmitter PASCAL Ci4 LEVEL
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6.5.6.1
Setting the damping
Using an adjustable damping you can eliminate fast pressure changes or peaks from hav-
ing direct influence to the output signal. The set value in seconds corresponds to the time
constant of an exponential rise. After a sudden pressure change, it takes the damping time
to reach 63.2% of the actual pressure at the output. After the damping time has elapsed
three times, 95% of the pressure is reached.
Figure 24: Damping effect
The damping affects the current output as well as the displayed pressure value.
6.5.6.2
Setting of the measuring rate
When shipped, the transmitter is set to a measuring rate of 20 Hz, i.e. 20 times per second
the pressure is measured and the current is calculated and imprinted in the current loop.
When a particularly fast measuring rate is required, for instance to detect pressure peaks,
you can increase the measuring rate to 100 Hz. This can lead to the following restrictions:
Communication via HART can be disturbed by fast pressure changes.
The measuring signal can be noisier.
For this reason, you should only increase the measuring rate to 100 Hz if necessary for the
application.
Note: Devices with differential pressure cell (type CI4x4x) run with a fixed measuring rate
of 50 Hz. For these devices there is no option to set the measuring rate.
6.5.6.3
Upper and lower current limit
In the standard setting, the current output is limited at 3.8 and 20.5 mA, meaning a further
drop or rise in the measured variable does not change the current. You can freely select
these current limits for the lower limit between 3.8 and 4 mA and for the upper limit be-
tween 20 and 21 mA.
