Graco VPM 12, Instructions Manual

Page: 38 / 88

Operation
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41. Weigh the two buckets and use the net weight of
each dispensed material to calculate the actual ratio
of the dispensed material.
42. If the calculated ratio of the weighed materials does
not match the ratios displayed on the ADM, go to
step 1 to re-calibrate the flow meters.
43. If the calculated ratio of the weighed materials
matches the ratio displayed on the ADM, then navi-
gate to the System 3 screen and change the ratio
alarm percentage to the desired percentage.
44. If at any point in the future the ratio, flow rate, or
ambient temperature changes from what was used
while performing this procedure, go to step 1.
NOTE: If the ratio or flow rate is changed to a ratio or
flow rate that has not been calibrated by performing this
procedure, the system will generate a “Learning New
Setpoint” advisory. The system usually produces a good
dispense ratio during the learning process however the
advisory is generated to inform the user of the condition.
The system can store calibration data in its memory for
up to five different flow rates and ratios.
NOTE: If the ambient temperature changes significantly
from the ambient temperature seen while performing
this calibration procedure, the system will need to
“learn” the new temperature and the flow rate may need
to be decreased. If the original flow rate was 325 g/s at
68°F (20°C) and the temperature is now 46°F (8°C), the
user may want to select a flow rate of 150 g/s or
150 cc/s. The machine will not automatically be aware of
the temperature change but it will try to find the correct
dispensing properties to compensate for the new tem-
perature. If the ambient temperature changes signifi-
cantly, go to step 1. It is important for the system to learn
the new temperature because typical paste materials
increase viscosity significantly as the temperature
decreases below 68°F (20°C).