HF scientific 19998 Triple Validation Turbidimeter - 0-100 NTU User Manual
Page 19
TVT 1 (5/02)
13
Rev. 2.6 (.pdf)
calibrating simply press the
↵
↵↵
↵
button at this time. However, if you are satisfied and wish to
complete calibration on the 0.02 NTU level use the
tu
arrows to select the word YES on
the lower row of the display and then press the
↵
↵↵
↵
button to initiate calibration. Both the
CAL and STORE blocks will flash during the operation and the word YES will change to a
count down starting at 90. When the calibration procedure for the 0.02 NTU level is
complete the CAL and STORE blocks will stop flashing.
Note: Prior to exiting the calibration routine ensure that the process water is flowing
through the sample chamber. This will help prevent unwanted spikes in the outputs
from the instrument.
16. The word END will appear on the lower row of the LCD display.
Pressing either the MODE
button
or the
↵
↵↵
↵
button will complete calibration. If you
press the MODE button two times you will return to the AUTO mode.
Note: 1. At any point in time during calibration you can cycle through the required
calibration points (0.02 NTU, 10 NTU, and 100 NTU) by pressing either the
t
t
t
t
or
u
u
u
u buttons. This allows you to individually calibrate with a particular
calibration standard.
2. If you wish to exit the calibration mode you may do so at any time, prior to
initiating a calibration, by simply pressing the
t
t
t
t or u
u
u
u buttons until the word
“END” appears on the lower row of the display. Once you reach this point,
simply press the enter button.
6.0 Calibration by Comparison to Laboratory Measurements (Instrument
Offset)
In certain instances, you may wish to use an offset factor to calibrate your instrument
rather than performing a physical calibration of the instrument (as described in section
6.2). This procedure is not recommended in lieu of regular instrument calibration but it
can be used in situations where the number of instrument’s used makes regular
calibration prohibitive. This calibration technique will make the instrument accurate only
at turbidity levels in the immediate vicinity of the grab sample and not in the full range of
the instrument.
The procedures are as follows:
1.
Collect a grab sample of the process water that is being monitored by the instrument and