To set the prism wash parameters for a given sensor, first select the sensor, then select. This menu contains the following alternatives (factory settings are given in parentheses):
|1||PRECONDITION TIME||0 … 30 s (0 s)|
|2||WASH TIME||0 … 30 s (3 s)|
|3||RECOVERY TIME||0 … 30 s (20 s)|
|4||WASH INTERVAL||0 … 1440 min (20 min)|
|5||WASH CHECK MODE||(Disabled)|
|6||HOLD DURING WASH||(Active)|
|7||TEMP LIMIT ACTIVATION|
|8||TEMP LIMIT VALUE °C|
|9||EMPTY PIPE CHECK||(Active)|
|1||WASH nD LIMIT|
|2||WASH TOLERANCE TIME||(0 min)|
The prism wash cycle: The timing of the wash cycle is controlled by the WASH INTERVAL, PRECONDITION TIME, WASH TIME and RECOVERY TIME settings. If the WASH INTERVAL is set to 0, the wash can be initiated only by using the manual wash or remote wash request. For more information, see Figure 3 and Wash cycle.
If the PRECONDITION TIME is 0 (or there is no relay configured for preconditioning), the preconditioning phase is skipped. If the WASH TIME is 0 (or there is no relay for wash), the wash functionality is completely disabled.
Wash check: The prism wash check monitors automatically that the wash really has an effect on the prism. In the WASH CHECK STANDARD mode, prism wash is accepted if the refractive index nD either falls below wash nD limit (default 1.34) at NORMAL OPERATION or NO SAMPLE occurs. This is the indication of a successful wash with water or steam.
If the wash is not accepted, the diagnostic message PRISM WASH WARNING is shown. If no wash is accepted during wash tolerance time, the message becomes PRISM WASH FAILURE. Both messages and the wash tolerance counter are reset by a successful wash. For more information, see Diagnostic message priorities.
The WASH CHECK AUTOMATIC WASH CUT mode differs from the standard mode by stopping the wash 2 s after the nD falls below the limit.
To stop the measurement for the duration of the prism wash, choose HOLD DURING WASH and in that menu activate the hold function. The CONC reading and mA output are held in the value they had immediately before starting the wash cycle.
To activate (or deactivate) a temperature limit, choose TEMP LIMIT ACTIVATION and then the appropriate command in the menu.
To set a low temperature limit, choose TEMP LIMIT VALUE °C and enter the temperature (in °C) where the limit should be.
The empty pipe check prevents washing if message is NO SAMPLE, meaning there is no process liquid in the pipe. To deactivate (or active) the empty pipe check, choose EMPTY PIPE CHECK and then the appropriate menu command.
To change the wash nD limit, select MORE... and then WASH nD LIMIT to set the nD value to be used with the wash check functionality.
To set wash tolerance time, select MORE... and then WASH TOLERANCE TIME to set the time during which a wash must be accepted. If no wash is accepted during wash tolerance time, the message becomes PRISM WASH FAILURE. The wash tolerance counter is reset by a successful wash.