K-Patents PR-21-S - Manual (Page 64)

58 PR-21-S instruction manual
Note: For safety reasons two sensors never wash simultaneously. If the manual
wash button for sensor A is pressed while sensor B is washing, the wash cycle for
sensor A is started after B has finished. Similarly, if the interval time for sensor B
elapses when A is washing, the wash for sensor B is delayed until A has finished.
In case of remote wash request the request is discarded if it arrives when the other
sensor is washing. The request is honored only if the contacts are held closed until
the other sensor has finished.
The wash relay is closed for the wash time specified in the wash settings. If the
wash auto-cut functionality is active, the wash may be ended earlier (see Fig-
ure 6.16). The specified wash time is never exceeded.
After the wash phase is completed, a recovery time is spent. During the wash cycle
(precondition, wash, recovery) the measurement result is in hold unless otherwise
specified.
Preventing automatic wash:
The preconditioning and wash relays are never activated by the automatic wash
control:
− Under the diagnostic message
NO SAMPLE (see Section 8.2.6) as this indicates a
clean prism in an empty process line. The diagnostic message is WASH STOP/NO
SAMPLE .
− If a wash stop input switch is closed (see Section 6.4), indicating e.g. that there
is no process flow. The diagnostic message is EXTERNAL WASH STOP .
− If the process temperature limit is activated and the temperature falls below
the limit, indicating that the process is not running. The diagnostic message is
LOW TEMP WASH STOP