8
4.0 Operation
This process monitor allows for the measurement of the transmittance
of process water on-line. Process water is usually reported in units
of %T. Readings above 102 %T are indicated by a flashing display.
Readings above 100 %T indicate that the current sample is better than
the calibration water. Readings above 110 %T are not possible. All
readings are path length corrected to 10 mm.
Alternately measurements can be taken in Absorbance. Negative
Absorbance readings indicate the need for a calibration or that the
water tested is better that what the instrument was calibrated to. These
readings show ABS on the lower line of the display. All readings are
path length corrected to 10 mm
During normal operation, the instrument will have the arrow beside
AUTO
. The scale (% T or ABS) is displayed on the lower row of the
display and the measured reading on the upper row of the display
(see illustration below). The user needs to keep in mind
that the instrument only updates at periods determined in
the configuration or
CONFIG
menu. Refer to section
7.14
Lamp Duty Cycle
.
4.1 Warm-up
Upon power-up the AccUView LED will require a warm-up period of about
30 minutes. For improved accuracy, allow the AccUView LED to compete
warm-up time prior to calibrating. During the warm-up period, the display
may flash indicating that it has detected a temperature change. It is normal
for this to occur during the warm-up period.
4.2 Routine Measurement
The following steps describe how to measure the % T or ABS of a sample
using this instrument:
1. Apply power to the instrument and allow the unit an initial warm up
of 30 minutes.
2. When a continuous process stream is flowing through the
instrument, the instrument will display the measured % T or ABS
level of the sample by displaying it on the LCD screen. In addition,
the equivalent signal is provided on the analog (4-20 mA) output, or
the digital output, depending on the options selected.
A flashing display may occur after warm-up. This is an
indication that either the ambient or the water temperature
or has changed rapidly. During this time the readings may be
slightly out of the specified accuracy. The AccUView LED will
automatically compensate as soon as the rate of temperature
change slows.
NOTICE
4.3 Security Access Feature
The instrument is equipped with a security access code feature that can
be activated in the configuration mode. If the security feature is enabled,
the screen shown in the illustration below will appear when the
MODE/EXIT
button is pressed.
The security code (333) must be entered to gain access to
CAL
or
CONFIG
menus. Notice that the first number in the code is flashing.
The flashing indicates that this is the number to be entered. Use the
or
arrows to select the first of the three numbers in the code and
then press the
button to accept the first number of the code. Now
enter the second number in the code. Proceed as with the first number
followed by
. Then repeat the process for the third number in the
access code, and finish with the
button.
If the valid access code has been selected, the instrument will be
directed to the calibration mode. If the CONFIG mode is needed push
the MODE/EXIT button one more time.
If the wrong access code is selected, the instrument will
return to the AUTO mode. Refer to section
7.6 Enabling the
Security Access
for more information.
4.4 Initial Operation
It is recommended to check that cuvette is tightly installed on the flow
through unit prior to the introduction of water. These are pressure checked
at the factory but due to shipping the cuvette could have loosened.
For the best accuracy an initial calibration is recommended. These are all
factory calibrated but the best accuracy is achieved by calibrating with
DI water with the flow through locked in place prior to calibration. Do not
move the flow through after calibration, but simply start the fluid flow. Refer
to the next section for complete calibration instructions.
