Hach HT 200 S, Basic User Manual

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English 7
Language selection
The thermostat software supports several languages. Press key 1 when
you switch on the thermostat.
Press
key 4 to scroll to the required language.
Then confirm the selection by pressing key 3 under the language
symbol .
The language is changed immediately and the start menu appears on
the display.
Main menu
Overview of menu items
Digestion times
After selecting the 100 or HT standard program, the Time sub menu
appears automatically; this sub menu is used to select the digestion
duration/time.
Standard program 100
The digestion temperature is 100 °C. The Time sub menu then appears;
this sub menu is used to select the required digestion time.
The following digestion times can be selected for a digestion
temperature of 100 °C: 30, 60 and 120 minutes.
Standard program HT
The digestion temperature is 150 °C or 170 °C. The Time sub menu
then appears; this sub menu is used to select the required digestion
time.
The following digestion times can be selected at a digestion temperature
of 150 °C or 170 °C: 10, 15 and 30 minutes.
The temperature of 170 °C shown on the display corresponds to the
temperature of the heating block.
Note: The total digestion time consists of the selected digestion time and
the heating-up and cooling-down times. This time can vary depending on
the digestion temperature, the ambient temperature and the number of
round cuvettes and/or reaction tubes.
At this heating block temperature, different temperatures are reached
inside the digestion vessels, depending on the boiling point of the
substance to be digested:
• Aqueous solutions containing diluted acids and lyes reach 150 °C
(e.g. LatoN, LCW 902 crack set,
phosphate cuvette tests etc.).
• Semi-concentrated and concentrated acids (all COD cuvette tests)
reach
170 °C .
Standard program COD
The digestion temperature is 148 °C and the digestion time is
120 minutes (heating-up time included). In this program, it is not
possible to select the digestion time.
COD digestion can be started immediately at 148 °C and 120 minutes.
Figure 5 Main menu — key assignment
Note: Wait at least 20 seconds before restarting the instrument in order
to avoid damaging its electronics.
Overview of additional menu items
Press key 4 to display additional menu items PRG (Programming),
VAR (Varying) and CPRG (Delete).
1 Key 1 3 Key 3
2 Key 2 4 Key 4
4 3 2 1