Dukane iQ Series User Manual page 79

Section 5 - System Operational Testing
Overview
An iQ Series generator must be operating and connected
to the press/thruster in order to test the system.
For efficient operation of a Dukane ultrasonic assembly
system, the ultrasound signal from the generator must
match the frequency and phase angle (vibrational charac-
teristics) of the stack that is being driven. Each stack has
unique vibrational characteristics dependent on the combi-
nation of stack components. In addition, the characteristics
of a particular stack may vary slightly during operation
because of temperature and loading factors.
To match the generator output signal with the character-
istics of a particular stack, the generator output frequency
is adjusted by Dukane's patented phase-locked-loop Digi-
Trac pulse-width modulation circuitry.
The Digi-Trac feature automatically adjusts the ultrasound
signal to match the vibrational characteristics of the stack
being driven. When the ultrasound turns on during each
operating sequence, the Digi-Trac circuit monitors the
motion of the stack on a frequency cycle-by-cycle basis
and adjusts the ultrasound signal for the optimum setting.
Because the Digi-Trac continuously monitors each operat-
ing sequence, it compensates for vibrational changes that
occur during repeated operations due to heating of the
stack components. It also compensates for changes that
occur over longer time periods due to aging of the piezo
electric crystals in the transducer, or possible wear of the
ultrasonic horn.
The Digi-Trac feature excels in environments hostile to
reliable operation, such as high duty cycles or high stress,
and continuous-duty applications. In such situations, the
Digi-Trac circuit compensates for the unique vibrational
characteristics of each stack due to differences caused by
aging, loading, temperature changes, and differences in
horn configurations.
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Dukane Manual Part No. 403-575-00