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2.1 Weight Ratio Dispensing: Parameter Guide,
1082 Silicone: #15 & #24
The following information should be used as a general guide in selecting optimal dispensing
parameters: This data was collected with a 600 RPM LabTec™ Dispenser mounted with a 1082 pump
head; the “Tube Size” parameter refers to thick walled silicone pump tubing size #24.
The “Slow Factor” is implemented at the end of each dispensing cycle to allow the electronic scale to
stabilize. Thus a Slow Factor of 20.00 mL indicates that the last 20 mL will be dispensed at reduced
pump speed.
The end of the dispensing cycle will be indicated by a “beep” followed by the display “Dispensing
Completed”. The “Sniffle”, i. e. momentary pump reversal at the end of the dispensing cycle, is set at
its default value of 0.3.
Edit Parameter Settings: All dispensing was done with #24 Silicone pump tubing
EDIT 1: Wgt Factor = 9.00, Sniffle = 0.3, Slow Factor = 20.00 gr, Pump Rate = 80%,
Time Delay = 00:00, Count = 1
EDIT 2: Wgt Factor = 99.00, Sniffle = 0.3, Slow Factor = 20.00 gr, Pump Rate = 80%,
Time Delay = 00:00, Count = 1
Sample Theoretical Ave. Delivered Dispensing Time
Weight
Diluent Weight Diluent Weight
RSD (%)
per Aliquot
EXEC 1: Wgt. Factor = 9.00
10.00 gr 90.00 gr 89.99 gr 0.12% 12 sec
20.00 gr 180.00 gr 180.03 gr 0.04% 16 sec
EXEC 2: Wgt. Factor = 99.00
1.00 gr 99.00 gr 99.01 gr 0.11% 11 sec
2.00 gr 198.00 gr 198.00 gr 0.07% 18 sec
Note: The LabTec™ will stop pumping just prior to reaching the target weight; once the scale has
stabilized, the LabTec™ will complete the dispensing cycle.
Note: Weights were used as surrogate samples. Weight sizes: 1.00 gr, 2.00 gr, 10.00 gr and
20.00 gr were placed on PGS Mettler scale. Distilled water was used as a diluent; five (5) separate
measurements were made for each of the four (4) sample weights, their average Delivered
Diluent Weight and the Relative Standard Deviation (RSD) are summarized above.
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