9
5.0 Instrument Calibration
The instrument was calibrated and tested prior to leaving the factory.
Therefore, it is possible to use the instrument directly out of the box.
Under normal conditions, re-calibration is recommended at least once
every month. To get the greatest accuracy, you may need to calibrate
once per week.
Two cuvettes are supplied with the instrument so that they can be
exchanged with each other. One cuvette should always be kept clean
for replacement when calibrating.
The instrument is designed to store the last reading prior to calibrating.
Relay contacts are held at the last valid condition and will not change
state while the instrument is in the calibration mode. The 4-20 mA is
also held at this stored reading and will not change until is calibration
is complete. Thirty seconds after completion of the calibration the
AccUView LED will start will start taking online measurements which will
be averaged with the stored reading (depending on setting). In order
to prevent disruptions in data the operator should release the clamp to
allow the sample water to flush out the calibration water as soon as the
calibration is completed.
While in the calibration mode, the instrument has a time-out feature
that automatically returns the system operation to the
AUTO
mode
after a fifteen (15) minute period of inactivity.
5.1 100 %T Calibration
1. Select the calibration function of the instrument by pressing
the
MODE/EXIT
button once. The arrow beside
CAL
will be
illuminated on the display. The lower display shows alternating
100
(indicating that the 100%T standard is requested) and
.
The last reading has now been stored and the equivalent reading is
being output on the 4-20mA signal. This output will be held after the
instrument returns to AUTO, allowing time for the flow to be restarted.
2. Close off the flow of water using the shutoff clamp.
3. Remove the flow through cuvette, and retain for future cleaning
and use.
4. Fill the second clean cuvette with 100% T calibration fluid and
reinstall the filled cuvette tightly on the flow through unit.
5.
Wipe flow through unit dry
, install and lock in place.
6. Press the
button to start the calibration.
7. The upper display will count down the progress of the calibration step.
8. The instrument will return to
AUTO
mode at the end the calibration.
9. The shutoff clamp should now be released to restore sample flow.
10.
Do not move flow head after calibrating.
Before starting the calibration procedure, be sure to turn off
the instrument’s ultrasonic cleaning option. See section 7.10
for instructions.
NOTICE
5.2 ABS Calibration
1. Select the calibration function of the instrument by pressing
the
MODE/EXIT
button once. The arrow beside
CAL
will be
illuminated on the display. The lower display shows alternating
0
(indicating that the 0.000ABS standard is requested) and
. Once
in the calibration menu the last reading has now been stored and
the equivalent reading is being output on the 4-20mA signal. This
output will be held after the instrument returns to AUTO, allowing
time for the flow to be restarted.
2. Close off the flow of water using the shutoff clamp.
3. Remove the flow through cuvette, and retain for future cleaning and use.
4. Fill the second clean cuvette with 100% T/0.000 ABS calibration fluid
and reinstall the filled cuvette on the flow through unit.
5.
Wipe flow through unit dry
, install and lock in place.
6. Press the
button to start the calibration.
7. The upper display will count down the progress of the calibration step.
8. The instrument will return to
AUTO
mode at the end the calibration.
9. The shutoff clamp should now be released to restore sample flow.
10.
Do not move flow head after calibrating.
Since the instrument stored the reading previous to calibration, the
previous reading may appear after calibration for at least 30 seconds. The
reading will then update to the current reading. How fast this upgrades
occurs depends on the
CONFIG
settings for
RESP
(response time) and
UV-T
(lamp duty cycle).
There is no need to recalibrate when changing ranges from %T to ABS or
the reverse.
It is recommended that the flow through unit be removed for as
short an interval as possible to prevent premature saturation of
the desiccant.
NOTICE
CAUTION
!
The UV lamp is of very low power but is recommend to avoid
looking directly into the optical well while the flow through unit
is removed.
Before starting the calibration procedure, be sure to turn off
the instrument’s ultrasonic cleaning option. See section 7.10
for instructions.
NOTICE
