Using a manual flow cell, Using an automated flow cell, Select static or dynamic mode – Hach-Lange 2100 AN Laboratory Turbidimeter User Manual User Manual
Page 37: Select the fill time
• For short-term storage (a few hours), flush the system with distilled or
deionized water and leave the flow cell full of the flush water to
minimize air locks and build up of residue on the parts.
• For long-term storage, disassemble, fully clean and air dry all parts.
Using a manual flow cell
To set the flow rate, increase the height of the collection drain assembly
on the support rod to decrease the flow rate. Make sure that the bottom
of the collection drain assembly is no lower than 7.5 cm (3 in.) above the
support stand base.
To flush the flow cell, lower the collection drain assembly to the support
stand base to flush the flow cell.
Using an automated flow cell
Change the position of the valve-control switch on the flow valve module
to control the flow manually. The valve-control switch has three
positions:
• Continuous Open—The flow valve is open.
• Closed—The flow valve is closed.
• Momentary Open—The flow valve is open while the switch is pushed
down and held to the Momentary Open position. When the switch is
released, the switch goes back to the Closed position and the flow
valve closes.
Set the valve-control switch to the Closed position for automated
operation of the flow valve module. In automated operation, the
instrument controls the flow.
Select static or dynamic mode
In automated operation, the instrument can make flowing (dynamic) or
not flowing (static) sample measurements.
Static mode:
1. The flow valve opens for the selected fill time. Refer to
on page 35. The flow cell fills and removes the previous
sample from the system.
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
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
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
on page 35. 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
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
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.
English 35