K-Patents DD-23 - Manual (Page 21)

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Only one refractometer in operation:
When only one instrument is in operation the divert action takes place if this instru-
ment reads 58 % or below. The rule selection has no in󰅮luence on the divert decision
in this case.
A or B
under 58% unsafe
over 58% safe
Table 5.4 Operation logic when only one instrument operating
No refractometer in operation:
If both instruments are out of operation (due to malfunction or maintenance), then
according to BLRBAC divert action must take place.
Emergency divert
In all cases the system may be set to DIVERT by pressing the EMERGENCY DIVERT button
(or an external emergency divert button, see Section 2.3.8).
5.3 Refractometer concentration measurement
For refractometer calibration consult also Chapter 6 in the separate Process refrac-
tometer PR-23 Instruction manual.
The CONC% displays of the two indicating transmitters have to show the same value
within 0.5 %. If there is a difference, this can be eliminated by adjusting the bias for
one of the refractomers; comparison with sample determination can decide which
one should be corrected.
In the PR-23 refractometer system, bias is the parameter
F00 , the third parameter in
the 󰅮ield adjustment parameter list. To change it, 󰅮irst press the MENU soft key, then
5 CALIBRATION , then 1 CHEMICAL & FIELD PARAMETERS and then 2 FIELD CALIBRATION PARA-
METERS . Choose 3 F00 (BIAS) to change the bias (see Section 6.2.5 in the PR-23 manual).
If the Indicating transmitter A displays 68.2% and B displays 68.8% , the difference can
be eliminated by lowering B by 0.6%. This is done by setting the 󰅮ield calibration
parameter
F00 to -0.6 in Indicating transmitter B.
Due to its digital measurement principle, the readings of the K-Patents Process refrac-
tometer do not drift by time. Frequent recalibrations based on of󰅮line moisture analy-
sis must be avoided, as they will introduce random 󰅮luctuations to the refractometer
readings.