Pr
o
Minent
®
Page 120
8.10.2.3
DULCOTEST
®
Redox (ORP) Sensor RHER-Pt-SE and DULCOTEST
®
Sensor PHEP or PHER for pH, Running-In
Running-In
Redox (ORP) Sensor
The
DULCOTEST
®
RHER-Pt-SE sensor for redox (ORP) must not be run-in. The DULCOTEST
®
RHER-Pt-SE sensor for redox (ORP) can be readily used.
pH
Sensor
The
DULCOTEST
®
PHEP or PHER sensor for pH must not be run-in. The DULCOTEST
®
PHEP or
PHER sensor for pH can be readily used.
8.10.2.4
DULCOTEST
®
Redox (ORP) Sensor RHER-Pt-SE and DULCOTEST
®
Sensor PHEP or PHER for pH, Calibration
Redox (ORP) Sensor
Having connected the sensor to the transmitter by means of the sensor cable (taking care that
connectors and cable remain absolutely dry), dip the sensor into a redox standardizing solution,
e.g. of 465 mV. The reading should reach or exceed this value within not more than 30 seconds.
If the reading rises rather sluggishly or falls short more than 20 mV, clean the sensor and repeat
check. If again unsuccessful, replace the sensor with a new one.
pH
Sensor
Since pH sensors are subject to certain manufacturing tolerances, they must be tuned to the
pertinent pH transmitter. The adjustment intervals depend on relevant operating conditions. They
can vary from a few days to up to 8 weeks.
Having connected the sensor to the transmitter by means of the sensor cable (taking care that
connectors and cable remain absolutely dry), dip the sensor into a pH 7 standardizing solution
and adjust transmitter exactly to read this value.
Remove the sensor, rinse it with water, preferably distilled water, and dry it by swabbing it with
soft, non-fl uffi ng tissue paper.
IMPORTANT
Do not rub since this might cause static electricity and false readings.
Immerse the sensor in a buffer solution differing by a least 2 pH from pH 7 and calibrate after the
value on the display has stabilised. If within 30 seconds a steady-state value is not produced or
calibration has proved impossible, clean sensor and repeat calibration. If again unsuccessful,
replace sensor with a new one.
Calibration
D2C
Calibration of the pH Sensor
The calibration of the pH sensor uses a two-point calibration method (zero point, slope). As
buffer pH 7 (zero point calibration) and pH 4 (slope calibration) are factory-set. If other buffers are
to be used, the defaults in the complete operating menu (menu A, B) may be altered. During cal i-
bra tion control is stopped and metering is reduced to the set base load. The output 0/4...20 mA
(meas ur ing value) will be frozen. After successful calibration, all fault determinations relating to
the meas ur ing value are started again. The current probe data (zero point/slope) will be displayed.
pH/Redox (ORP)
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