K-Patents PR-21-S - Manual (Page 67)

6 Configuration and calibration 61
6.7.2 Setting prism wash parameters
To set the prism wash parameters for a given sensor, first select the sensor, then
select
5 CALIBRATION from the Main menu, and then 4 PRISM WASH . This menu contains
the 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 0–120 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 (on next ’page’)
The prism wash cycle: See Figure 6.16 and Section 6.7.1. 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 zero, the wash can be initiated only by using
the manual wash or remote wash request.
If the PRECONDITION TIME is zero (or there is no relay configured for preconditioning),
the preconditioning phase is skipped. If the WASH TIME is zero (or there is no relay
for wash), the wash functionality is completely disabled.
The recommended wash times and wash medium pressures are given in Sec-
tion 4.5, “Recommended wash pressures and times”.
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 n
D
either falls below wash n
D
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 FAILURE (see Sec-
tion 8.4) will appear. This message is reset by a successful wash.
The
WASH CHECK AUTOMATIC WASH CUT mode differs from the standard mode by stopping
the wash 2 seconds after the n
D
falls below the limit.
To stop the measurement for the duration of the prism wash, choose 6 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 7 TEMP LIMIT ACTIVATION and
then the appropriate command in the menu.
To set a low temperature limit, choose 8 TEMP LIMIT VALUE °C and enter the temper-
ature (in °C!) where the limit should be.
The empty pipe check prevents washing if message is NO SAMPLE , i.e. there’s no
process liquid in the pipe. To deactivate (or active) the empty pipe check, choose
9 EMPTY PIPE CHECK and then the appropriate menu command.
To change the wash n
D
limit, select first 0 MORE ... and then 1 WASH nD LIMIT to set the
n
D
value to be used with the wash check functionality.