5 Pressure Measurement
The Cerabar S is immediately ready for measurement. The measuring range and
pressure units correspond to those on the nameplate. The acting pressure is always
transmitted via Foundation Fieldbus in these units. Other settings are possible via a
configuration tool.
It is not possible to adjust zero and span in the conventional sense. The resolution of the
measured value, however, is such that the specified accuracy of 0.1% of span is offered
for "turndowns" down to 20:1. The "turndown" can be displayed via a configuration tool
and the bargraph. This chapter contains the following information:
•
Calibration with keys
•
Calibration via tool
•
Damping
•
Locking/unlocking of the manufacturer´s-specific parameters
•
Analog input block parameters
•
Measuring point information
5.1 Calibration with keys
By using a reference pressure, the zero and span for the bargraph can be adjusted. The
maximum turndown is 20:1.
Calibration without
reference pressure
The lower and upper range values required are set with keys.
# Key Entry
1 Set the lower range value by
repeatedly pressing the +Z and –Z
keys
(As the span remains constant, the
upper range value is shifted to the
same extent as the lower range
value.)
2 Set the upper range value by
repeatedly pressing the +S and –S
keys
(The lower range value is unaffected.)
Calibration with
reference pressure
A reference pressure which corresponds exactly to the desired zero and span is
available.
# Key Entry
1 Exact pressure for zero is acting
2 Press +Z and –Z once simultaneously
(As the span remains constant, the
upper range value is shifted to the
same extent as the lower range
value.)
3 Exact pressure for span is acting
4 Press +S and –S once simultaneously
(The lower range value is unaffected.)
–
–
+
+
Z
S
–
–
+
+
Z
S
–
–
+
+
Z
S
–
–
+
+
Z
S
–
–
+
+
Z
S
–
–
+
+
Z
S
–
–
+
+
Z
S
–
–
+
+
Z
S
BA211Y34
5 Pressure Measurement Cerabar S FF
32 Endress+Hauser
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