-9-
4.0 Operation
This process turbidimeter allows for the measurement of the turbidity of process water on-
line. The turbidity of the process water is usually reported in
N
ephelometric
T
urbidity
U
nits (NTU), but may be reported in
F
ormazin
N
ephelometric
U
nits (FNU). Readings
above 100 NTU are outside the range of this instrument. Readings above 100 NTU will
cause the display to flash indicating an over range condition
During normal operation, the instrument will have the arrow beside
AUTO
highlighted
with the current scale displayed on the lower row of the display and the measured reading
on the upper row of the display (see illustration below).
4.1 Routine Measurement
The following steps describe how to measure the turbidity of a sample using this
instrument:
1.
Apply power to the instrument and allow the unit to warm up (typically 45 minutes
–
1
hour on initial commissioning).
2.
When a continuous process stream is flowing through the instrument, the instrument
will display the measured turbidity 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.
4.2 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 changed. 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 wrong access code is selected, the instrument will return to the
AUTO
mode.
Refer to section 7.7
Enabling the Security Access
for more information.
