K-Patents PR-21-S - Manual (Page 51)

6 Configuration and calibration 45
0 10 20 30 40 50 60 70 80 90 100 110 120
Time [s]
52
54
56
58
60
62
64
66
CONC [%]
0.05 /s
0.2 /s
0.5 /s
Figure 6.3 Slew rate damping
When the measurement result is in hold, the displayed concentration value and
mA output do not change. The diagnostic values (e.g. n
D
) shown on-screen always
reflect the actual state of the measurement.
The measurement hold takes place after the CALC value and field corrections have
been calculated but before the signal filtering (damping) takes place (see Sec-
tion 6.6). If the hold is on, the output filter remains in its earlier state, and the
output signal is stationary. If the hold is started when there is no output signal
(e.g. no sample on the prism), there will be no measurement signal during the
hold.
6.2.1 External hold
When a switch input is configured for external hold functionality (see Section 6.4),
and the switch contact is closed, the measurement result is in hold. The measure-
ment result is kept in hold until the switch contact is opened. A status message
EXTERNAL HOLD will be shown.
6.2.2 Hold during wash
When the setting "Hold during wash" (see Section 6.7.2) is configured ACTIVE , the
output signal is in hold when the instrument is washing. The signal will be in hold
during all three phases (preconditioning, wash, recovery) of the wash process.
This setting can be used to avoid dips in the measurement signal during the prism
wash.
6.2.3 Tolerance time
The tolerance time setting can be used in processes where there are intermittent
breaks in the measurement due to non-representative sample on the prism. This
typically occurs when there are large voids in the process liquid.
If the optical image can be interpreted, the tolerance time setting does not have
any effect. When the optical image can no longer be interpreted (status messages,