10
2 Description
It measures the last preceding dispensing cycle relative to a reference measurement
previously recorded and found to be o. k. All adjustments have to be done in the setup
menu of the controller, to make sure that authorized personnel can store this reference
value only. Tolerance can be adjusted in 3 preadjusted ranges (low = 15%, middle =
35% or high = 55%) or from 1 to 99% to define the optimum between frequent false
alarms and reliable fault detection, see operating manual of the used controller. This
value affects the tolerance of the monitored parameters of integral and length of
envelope curve.
Referred to the length of the envelope curve the tolerance value actually indicates
accuracy in %. An air bubble, a clogged needle or a needle touchdown each has a very
strong effect on the envelope curve length of the pressure characteristic. Therefore this
is generally the governing parameter for dispense monitoring.
Ten different dispense quantities can be monitored by the controller. The order of storing
is fixed, but the reference can be selected per user’s own choice. The advantage is, that
different quantities on various work pieces can be preselected according to the user’s
requirement via the serial interface.
3
W
Luftblase
Air bubble
Aufsetzer
Needle touch-down
Normaler Druckverlauf mit Schneckenpumpe
Normal Pressure characteristic with Rotor Pump
250 ms 500 ms 750 ms 1000 ms 1250 ms