Hach-Lange 2100 AN IS Laboratory Turbidimeter User Manual - Manual (Page 34)

2. The flow valve closes when the fill time interval ends. The last portion
of sample flowing through the flow cell is held so that sample volume
measurements can be made for the selected measurement time.
Refer to
Select the measurement time on page 32.
A measurement is completed and the display is updated about once
every second.
3. The readings on the display of the instrument are sent at the
selected print time interval to the internal printer (and/or through the
RS232 output to an external printer or computer). Refer to
Configure
the printer output on page 35.
4. At the end of the selected measurement time, the final reading is
held on the display and sent to the internal printer (and/or through
the RS232 output to an external printer or computer). The FLOW
light flashes.
Dynamic mode:
1. The flow valve opens for the selected fill time. Refer to Select the fill
time on page 32. The flow cell fills and removes the previous
sample from the system.
2. The flow valve stays open when the fill time period ends.
3. Measurements are made on the dynamic (flowing) sample stream as
it moves through the flow cell for the selected measurement time.
Refer to
Select the measurement time on page 32.
A measurement is completed and the display is updated about once
every second.
4. The readings on the display of the instrument are sent at the
selected print time interval to the internal printer (and/or through the
RS232 output to an external printer or computer). Refer to
Configure
the printer output on page 35.
5. After the selected measurement time, the flow valve closes and the
final reading is held on the display. The final reading is sent to the
internal printer (and/or through the RS232 output to an external
printer or computer). The FLOW light flashes.
Select the fill time
The fill time is the time interval that the flow valve stays open so that
sample flows through the flow cell before measurements are taken.
Set the fill time from 0 seconds to 99 minutes and 99 seconds.
A fill time setting of 0 seconds causes the instrument to start
measurement immediately.
Use the flow cell specifications in
Table 3 to calculate the correct fill time.
Make sure that the fill time includes time to fill the system and to fully
remove the previous sample from the system.
Table 3 Automated flow cell specifications
Specification Details
System flow rate 250 mL/minute
System volume
(from the discharge of the inlet reservoir
to the outlet of the flow cell, not
including the 350 mL inlet reservoir) 30 mL (fill time = 8 seconds)
Purge volume 120 mL (fill time = 30 seconds)
minimum
Recommended to fully remove the
previous sample from the system.
1
1 A shorter fill time may be used when the same sample is being measured
again and again.
Select the measurement time
The measurement time is the time interval that the instrument measures
the sample.
A measurement is completed and the display is updated about once
every second.
Set the measurement time from 0 to 99 minutes and 99 seconds
(minimum=15 seconds).
A measurement time of 0 provides continuous measurement until FLOW
is pushed.
Note: A measurement time of 0 is not recommended for static mode because
particles in the sample may settle over time. The measured turbidity may be lower
than the actual turbidity.
Measurement notes
Before measurement, select the printer to use and the print time interval.
Refer to
Configure the printer output on page 35.
32 English