Jesco EASYPOOL SMART 02, Руководство по эксплуатации

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0 | EASYPOOL SMART 0 Operating Manual
Controller
Buffer 2: Transconductance calibration
Accurately clean the electrode with deionised or distilled water
before calibration of the resistivity.
NOTICE!
Avoid rubbing off glass electrodes as this will pro-
duce a static charge on the electrode. This would
result in faulty readings.
For slope calibration a buffer solution must be used which differs
at least pH units from the zero point. For zero-point calibration
a buffer solution of pH 9.7 is available from the manufacturer.
If you are using a different buffer solution for transconductance
calibration, the value for this buffer solution must be set on the
controller. When immersing the single-rod measuring cell in the
buffer solution (Ph = 9.7), a theoretical voltage of -134 mV
should be displayed. The physical value actually measured is,
however, always different from the theroretical one. Confirm pre-
setting by pressing the “OK“ key.
Then the slope value of the combination electrode is displayed.
In accordance with the DIN Standards 1965 the resistivity if an
electrode should range between 5 and 59 mV per pH-value.
The zero-point stability and reasonableness of the transconduct-
ance are monitored.
IMPORTANT!
If the transconductance reading differs considerably
from these values, check the single-rod measuring
cell or the connecting cable and the plug connectors.
Should zero-point and resistivity values of the com-
bination electrode exceed the admissible tolerances,
the system notifies the operator with a warning mes-
sage. In this case provide for immediate replacement
of the electrode.
IMPORTANT!
Store buffer solutions in a cool and dark place! Con-
sider its durability. Make sure that the buffer solution
is not contaminated. That is why you should not put
single-rod measuring cells directly from one buffer
solution into another solution.
1-point calibration
Main menu >> Calibrate >> pH value >> 1 point
Single-point calibration may also be used for pH calibration with
a single-rod measuring cell (see section 6, menu 1.).
Submerge the pH combination electrode in a buffer solution
which is equivalent or close to the zero point of the electrode.
The ideal zero point (O mV) of the combination electrode is pH
7.00, the actual zero point, however, deviates slightly from this
value. The manufacturer provides a buffer solution with pH value
of 6.80 for zero-point calibration. When immersing the pH single-
rod measuring cell in this solution, a voltage of 1 mV can be
displayed theoretically. The physical value actually measured is,
however, always different from the theroretical one.
When the physical value on the display becomes stable, you may
save the calibrated value by pressing „OK“.
Now enter the resistivity of the electrode.
IMPORTANT!
Should the actual measured voltage strongly differ
from the design zero-point of the electrode, it means
there is a zero-point drift of the electrode. Zero-point
drift should not exceed the specifications of the DIN
Standards 19265 (±40 mV).
Offset compensation
In accordance with DIN 19643, the control of the pH value is to
be made with an electrical metric pH value measurement.
By external influences it can be possible that the pH value of
the electrical metric measurement, measured by hand with the
photometer, deviates by a constant value. The "Offset compensa-
tion" menu allows you to compensate for this difference (setting
range +/- 0.30 pH).
NOTICE!
The offset value is set to „0“ after every new calibra-
tion.
4.5.3 REDOX potential measurement input
The REDOX potential is measured using the REDOX single-rod
measuring cell. It measures the voltage which exists in the water
due to oxidizing and reducing ions.
NOTICE!
For saline bathing water use a RESOX single-rod
measuring cell with a gold electrode instead of a
platinum electrode.
Calibration
Main menu >> Calibrate >> REDOX
Calibrate the combination electrode during startup. To calibrate
the REDOX single-rod measuring cell only one reference value
must be set. The physical value (mV) measured at the sensor is
shown on the display during calibration.
To calibrate you need a buffer solution in order to measure a
defined voltage in conjunction with the REDOX single-rod meas-
uring cell (default value: 468 mV). This value can be changed
when using other buffer solutions and/or combination electrodes
with other electrolytes. To change, use the buttons on the control
panel. The voltage actually measured is shown on the display
during calibration. This value has a small deviation from the given
value of the buffer solution. The deviation should not be bigger
than approx. 10%.
The accuracy of resistivity measurements is monitored through-
out the process.
After a reaction time (approx. 1 minute) the physical value does
not change anymore.
The reference value can be now entered and saved by pressing
the “OK” button.
IMPORTANT!
With old combination electrodes the response time
can become larger and vary. Furthermore the meas-
ured value can be largely different from that of the
buffer solution. This signifies that the combination
electrode must be checked and possibly replaced.