Hach DR/820 - Alternate Chemical Forms; Using the Timer; Using the Timer in Manual Mode

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SECTION 3, continued
key toggles between alternate forms, if any. See Appendix A for
currently available chemistries and their alternate forms.
3.2.5 Alternate Chemical Forms
Many Hach programs provide alternate chemical forms for the
measured parameter. Press the
CONC key to scroll through these
alternate forms after the measurement is displayed. Each press of
the
CONC key takes the user to the next alternate chemical form.
For example: In Program #1, mg/L Al may also be displayed as
mg/L Al
2
O
3
. If alternate forms are not available, the instrument
returns to its original form and reading.
3.2.6 Using the Timer
Many Hach test methods use one or more timers which are pre-
programmed into the DR/800 Series Colorimeters. When the
procedure instructs you to, press the
TIMER key to display a timer
interval. Press
ENTER to start the timer count-down. Several
beeps will sound at the end of a timer interval. If the method
requires additional timers, the instrument will automatically
display the next timer when the first timer elapses. Press
ENTER
to start the next timer.
To zero the instrument on the blank while the timer is running,
press the
EXIT key. The timer icon will continue to flash,
indicating the timer is running. Press
ZERO, or perform other
available functions within the method (such as blank correction)
while the timer is running. To return to the timer display, press the
TIMER key.
3.2.6.1 Using the Timer in Manual Mode
The manual timer function allows the operator to use the timer
independently from the method timer. Make sure the instrument
is not in numeric entry mode and activate the timer with a press of
the
TIMER key. If using a pre-programmed timer, press the TIMER
key again.
The “
#” action icon is illuminated, to indicate that the numeric
keypad is active. Enter the desired time using the numeric
keypad. For example, to enter 2 minutes, press
200, then ENTER.
To enter 12 minutes, press
1200, then ENTER. The display will
momentarily show the entered time, then the timer countdown