Operation
34
© Lutz-Jesco GmbH 2020
BA-42840-02-V03
Water sampling station
EASYPRO COMPACT
Operating instructions
7.
Hold the pH single-rod measuring cell in the buffer solution and move
back and forth for a short time.
8.
Enter the pH value of the buffer solution. This pH value serves as a
reference value for the device. The ideal voltage value and the current
voltage value is displayed in mV.
If these values deviate too greatly from one another, the best value is
displayed red. Too great a level of deviation is an indication that the
pH single-rod measuring cell needs to be replaced.
9.
Wait until the value has stabilised.
10.
Confirm the entry with the green checkmark.
11.
You will be requested to set the slope. Enter the slope.
12.
Confirm the entry with the green checkmark.
ü
1-point adjustment of the pH value completed.
9.5.1.3 Offset compensation
External influences can cause the pH value measured with the photome-
ter to deviate from the electrometric measurement of the pH value by a
constant value. The offset compensation enables you to compensate for
this constant difference (zero-point deviation).
Perform the following work steps:
1.
Working in the main menu under “Calibration”, navigate to the
“Sensors” tab.
2.
Working under “sensor”, select the sensor that measures the pH
value and which you wish to calibrate.
3.
Press the “Offset” button.
4.
You can enter a pH offset from pH -0.30 to max pH +0.30.
5.
Confirm the entry with the green checkmark.
ü
Offset compensation completed.
9.5.2 Redox value
The Redox value is measured using the Redox single-rod measuring cell.
The Redox single-rod measuring cell measures the voltage present in the
water due to oxidizing and reducing ions. You must calibrate the Redox
single-rod measuring cell during commissioning.
9.5.2.1 1-point adjustment of the Redox value
Pre-conditions for actions:
ü
A buffer solution is on hand for calibration.
Perform the following work steps:
1.
Working in the main menu under “Calibration”, navigate to the
“Sensors” tab.
2.
Working under “sensor”, select the sensor that measures the Redox
value and which you wish to calibrate.
3.
Press the “1 points” button.
4
1-point calibration begins.
4.
Shut off the sample water.
5.
Unscrew the redox single-rod measuring cell from the water
sampling station.
6.
Rinse the Redox single-rod measuring cell with water and dab it dry.
Rubbing can cause electrical discharge on the glass membrane,
which results in a delayed display.
7.
Hold the Redox single-rod measuring cell in the buffer solution and
move back and forth for a short time.
8.
Enter the voltage value in mV which is recorded on the buffer solution.
The voltage value entered and the current measured voltage value
are displayed in mV. If these values deviate too greatly from one
another, the best value is displayed red. Too great a level of deviation
is an indication that the Redox single-rod measuring cell needs to be
replaced.
9.
Wait until the value has stabilised.
10.
Confirm the entry with the green checkmark.
ü
1-point adjustment of the Redox value completed.
i
With older sensors, the reaction time can increase or the
measured value can differ considerably from the buffer
solution value. This indicates that the Redox single-rod
measuring cell must be checked and replaced if necessary.
9.5.3 3 electrode potentiostat
You should calibrate a 3-electrode potentiostat or the potentiostatic
measuring cells (chlorine sensors) as single-point calibration as a matter
of course. You will require a photometrically measured value in accord-
ance with the DPD method as a reference value.
i
With operation in a hot water system, electrochemical
processes on the measuring electrode can result in a displace-
ment of the zero point. In this case, 2-point calibration is
necessary in which you calibrate the zero point using
chlorine-free hot water. The second point is determined using
the DPD method with chlorinated water as usual.
9.5.3.1 1-point adjustment of a 3-electrode potentiostat
To calibrate chlorine sensors, you will require a photometer with which to
measure the reference value using the DPD method.
Pre-conditions for actions:
ü
A measurement device for determining the DPD value is already
present.
ü
The sensor is operated with sample water.
Perform the following work steps:
1.
Working in the main menu under “Calibration”, navigate to the
“Sensors” tab.
2.
Working under “Sensor”, select the sensor that you wish to calibrate.
3.
Press the “1 points” button.
4
1-point calibration begins.
4.
Take sample water in immediate proximity to the measuring cell and
confirm with “OK”.
5.
Determine the concentration in the sample water using the DPD method.
6.
Enter the measured concentration. This serves the device as a
reference value with which to permit correct measurement.
