K-Patents PR-21-S - Manual (Page 63)

6 Configuration and calibration 57
6.6.4 Entering field calibration parameters
The field calibration parameters supplied by K-Patents are entered by selecting
5 CALIBRATION from the Main menu, followed by first 1 CHEMICAL & FIELD PARAMETERS and
then by 2 FIELD CALIBRATION PARAMETERS .
Important: If there is already a previous field calibration, it should be cleared
(by setting all values to 0) before entering a new field calibration.
6.6.5 Direct BIAS adjustment
The concentration measurement value can also be directly adjusted by changing
the field adjustment parameter f00.
The value of the bias parameter f00 will be added to the concentration value:
NEW CONC = OLD CONC + f00 .
6.7 Configuring prism wash
In some applications the process flow does not keep the prism clean because of
sticky process medium or low flow velocity. In these applications the prism can
be automatically cleaned by installing a wash system (see Chapter 4).
The prism wash settings for sensors A and B are independent of each other. The
wash system is active if a relay has been configured to be a wash relay (see Sec-
tion 6.3) and the wash time is not zero. An automatic wash function can be config-
ured so that both sensors have different parameters.
6.7.1 Wash cycle
The wash logic is shown in Figure 6.15 as a flow diagram. The automatic prism
wash cycle (Figure 6.14) consists of three phases: precondition, wash and recov-
ery. The optional preconditioning function is used to e.g. blow out the condensate
before washing. After the preconditioning there is a one-second pause to avoid
having both precondition and wash relays active at the same time.
The wash cycle is initiated when the wash interval has elapsed. The wash can
also be started by closing an external switch (Remote wash, see Section 6.4) or
manually from the user interface at the Sensor status display (see Section 5.1.3).
The order of priority for these wash triggers is:
1. manual wash
2. remote wash request
3. wash interval timer
WASH
RECOVERY
INTERVAL
PRECOND.
Figure 6.14 The automatic prism wash cycle