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4.0 Weight Dispense Mode: Edit Menu, Continued
SUMMARY: In the Weight Dispense mode, the LabTec™ is connected to an electronic, toploading
scale while dispensing by weight. The SETUP: Scale submenu provides electronic scale options,
i.e. scales that can be interfaced with the LabTec™: Mettler, Ohaus, and Sartorius. The selected
scale is connected to port S1 on the rear panel of the LabTec™.
When executing the Weight Dispensing mode (press “Exec”) the LabTec
®
will display “SCALE
INITIALIZATION / Please Wait”. While this message is being displayed, the LabTec
®
checks the
scale communication. If scale communication is not possible the L a b T ec ™ w i l l d i s p l a y “ S C A L E
ERROR / Hit any key”. Check the RS 232 cable connection as well as the communications
parameters in the scale; also make sure you have selected the correct scale manufacturer in
the LabTec™ SETUP: Scale submenu.
DISP. WEIGHT: Defines the dispensed weight in terms of grams. For example, to dispense 50.00
grams, use the “Incr”, key to scroll to 50.00, then press “Select” Default = 100.00 gm.
CLEAR CV: This clears the Cumulative Volume (CV) value without having to cycle the system power,
which also clears this value. Press Yes, No, or Exit.
SNIFFLE: The SNIFFLE function consists of a brief pump reversal to suck in the droplet that
typically hangs at the end of the dispensing tip. The amount of pump reversal is userselectable
from 0 to 2.0 revolutions. The SNIFFLE function allows you to avoid carry-over between dispensing
cycles and provides for a cleaner dispensing environment. Default=0.0.
SLOW FACTOR: Defines the weight that is dispensed slowly at the end of the dispensing cycle.
For example, if the desired weight is 100.0 grams, then the SLOW FACTOR is selected to be
25.0 gm. When the LabTec™ initiates dispensing, the first 75 gm. will be dispensed at a high pump
rate (e.g. 80% of max.), while the last 25 gm. will be dispensed in a multiple step ramp down of flow
to avoid overshooting the diluent target weight. The SLOW FACTOR as well as the LabTec™ pump
rate is user-selectable. Default = 25.0.
PUMP DIRECTION: Defines the rotation of the pump head; this parameter can be changed from
clock-wise (CW, default) to counter clock-wise (CCW). Default = CW.
PUMP RATE: Defines the relative pump speed (0% to 100% of max.) with which the solution is
being dispensed. Typically, this parameter is set at 80% (default), however, a slower pump speed
is advisable if excessive back-splashing should occur.
TIME DELAY: Defines the time interval, in seconds, between dispensing cycles. Default = 1.0.
COUNT: Defines how often the dispensing cycle will be repeated. For example, when COUNT = 10,
then the selected DISP. WEIGHT will be dispensed 10 times. Default = 1.
Note: Use “Up” and “Down” keys to make a selection, then press, “Select” to implement the
selection.
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