HF scientific 19944 Triple Validation Turbidimeter - 0-100 NTU - Manual (Page 15)

TVT2 (5/02)
Rev. 1.7 (.pdf) 10
The security code has three numbers that are selectable one at a time. Notice that the first
number in the code is flashing; the flashing indicates that this is the number to be
changed. Use the
tor u arrows to select the value of the first number in the code and
then press the
↵ ↵↵ ↵
button to accept the first number of the code. After you have pressed
enter, the second number in the code will start to flash. Proceed as with the first number.
Then repeat the process for the third number in the access code.
If you have selected a valid access code, the instrument will be directed to either the
calibration or the user setup mode depending on the access code that was provided to the
instrument. If the wrong access code is selected, the instrument will return to the AUTO
mode.
Note: Only three access codes are used in the instrument: one for instrument calibration
(333), on for calibration by comparison/offset (555) and one for instrument
configuration (444); these codes are not programmable.
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. However, re-calibration of the
instrument is recommended to help you become familiar with the operation of the
instrument and the calibration procedures. Under normal conditions, re-calibration is
recommended at least once every three months
1 .
During calibration, the instrument performs several system self-diagnostics. As such,
several warning messages may be displayed. If the instrument detects an irregularity
with the instrument (detectors or lamp) a warning message will be displayed on the lower
row of the display on exit from the calibration mode. If this occurs please attempt to
rectify the warning message yourself, or contact the HF scientific, inc technical services
department. In any event, the instrument will continue to monitor the turbidity of the
process water with a decreased accuracy until the error is rectified.
In addition, if the instrument remains in the calibration mode for longer than 5 minutes
with no activity, it will time out and return to the automatic measuring mode.
1 The EPA recommends that on-line turbidimeters be calibrated with the primary standard (Formazin) at least once
every three months if they are to be used for EPA reporting.