Vaisala K-PATENTS PR-23 AX Series, Instruction Manual

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6 Configuration and calibration 45
defined tolerance time (see Section 6.2.3 for tolerance time). By default the QF thres-
hold value is -500.
6.2.5 Hold source interactions
There are three different reasons why the measurement signal may be in hold. All
three result in the same behaviour, but they also interact with each other.
Wash-related hold (Section 6.2.2) and external hold (Section 6.2.1) are connected in
parallel. If at least one of them is active, the measurement result will be in hold. Tol-
erance time (Section 6.2.3) is independent of these two, but the tolerance time will be
reset whenever there is another reason for the measurement hold.
For example, if the tolerance time is set to 10 seconds, and wash hold becomes active
after 7 seconds, the remaining tolerance time will be reset to 10 seconds After the
wash is over, there is still 10 seconds of tolerace time remaining.
6.2.6 Hold and signal damping
The signal filtering (damping) is stopped during hold. The last filtered value is shown
on the screen and set to the mA output (if the concentration output is configured).
Figure 6.5 illustrates this behaviour (gray areas represent the periods when the hold
is active).
0 50 100 150 200
Time [s]
40
42
44
46
48
50
52
54
56
58
60
CONC [%]
Original signal
Filtered (damped) output
Figure 6.5 Damping stops during hold