Calibrating Concentration Measurement; Figure 38 Default Ma Output Values - Vaisala PR-23 Series User Manual

PR-23 Series User Guide
• 5 DEFAULT OUTPUT sets a mA default output value that the instrument returns to in
certain malfunction situations. The value can be set to a low or high mA value, for
example, 3.0 mA or 22 mA. The factory setting for default output is 3.4 mA. For a list of
malfunctions that are affected, see
NAMUR is an international association of users of automation in process industries.
The association recommendation NE 43 promotes a standardization of the signal
level for failure information. The goal of NE 43 is to set a basis for proactively using
transmitter failure signals in process control strategies. Using these failure signals,
instrument faults are separated from process measurements.
NAMUR NE 43 uses the 3.8 ... 20.5 mA signal range for measurement information, with
≥21 mA or ≤3.6 mA to indicate diagnostic failures (see the following figure). With that
information, it is easier to detect a failure condition on a refractometer, for example, it
clearly tells you whether you have an empty pipe or a failed instrument.
failure
0 3.6
3.8
Figure 38 Default mA output values
• 6 SEC DEFAULT MODE and 7 SEC DEFAULT allow you to set a secondary mA output
value for empty pipe (message NO SAMPLE) to differentiate it from the other
messages that cause the measurement to revert to default mA. By default the
secondary mA output is disabled.
• 8 MANUAL SET allows you to set different output values to check the output signal.
Press the BACK key to return normal output function.
If you want to turn off the mA output, select NOT DEFINED in the Source menu.
7.4 Calibrating concentration
measurement
The concentration calibration is organized in six layers.
72
Diagnostic message priorities (page
Measurement Data
4
OK
IM-EN-PR23-E
97).
failure
mA
20 21
20.5