User Guide

5
IR LED
EMITTED LIGHT (890 nm)
CUVET
LIGHT
DETECTOR
90° SCATTERED
LIGHT
PRINCIPLE OF OPERATION
* 1 FTU = 1 NTU
HI 93703-11 has been designed to perform
measurements according to the ISO 7027 In-
ternational Standard.
The instrument functions by passing a beam of
infrared light through a vial containing the sample
being measured.
A sensor, positioned at 90° with respect to the
direction of light, detects the amount of light
scattered by the undissolved particles present
in the sample. The microprocessor converts
such readings into FTU* values.
As noted above, FTU unit is equal to the NTU
unit. However, there are other known measure-
ment units for turbidity: Jackson Turbidity Unit
(JTU) based on the old method of Jackson's
candle, and Silica Unit (mg /L of SiO
2
). For your
reference the conversion table between these
measurement units is shown below:
JTU FTU/NTU SiO
2
(mg/L)
JTU 1 19 2.5
FTU/NTU 0.053 1 0.13
SiO
2
(mg/L) 0.4 7.5 1
6
35
1
6
7
8
4
LOG LOBAT
TIME
DATE
LOGGING
MICROPROCESSOR
TURBIDITY METER
LOGGING
MICROPROCESSOR
TURBIDITY
METER
HI 93703-11
VIEW
STO
CLR
GLP
CAL
DATE
READ
ALT
OFF
ON
%
188
2
FUNCTIONAL DESCRIPTION
1) Measurement Cell
2) LCD (Liquid Crystal Display)
3) ON/OFF key / CLR key, to clear log memory
4) GLP key, to display last calibration date/
time / CAL key, to enter the Calibration
Mode
5) STO key, to store sample after reading /
VIEW key, to view log memory
6) READ key, to perform measurements /
DATE key to display (toggle) current date/
time
7) ALT key, to activate the ALT functions
(second function keys in orange)
8) RS 232 5-pin connector