The system uses electrostatic force to excite mechanical oscillation around the wire fundamental harmonic resonance
The oscillation amplitude is sensed by measuring the capacitance variation in the wire-tube system
Changing the high voltage modulation frequency mechanical resonance curve
Fully operated by a PC LabVIEW program
WTMTim ing unit
&ADC /DAC R/W
Tim ing unit
C o ntro l
C PU
&
RS232 inte rfa c e
PC se ria l p o rt
Se nso rM DT 1 C o m p a ra to r
HV m o d ula to r HVPo we r sup p ly
Sc a le r 1
Sc a le r 2
Se nso rM DT 2 C o m p a ra to r
Sc a le r 1
Sc a le r 2
Se nso rM DT 15 C o m p a ra to r
HV m o d ula to rHV
Po we r sup p ly
Sc a le r 1
Sc a le r 2
Se nso rM DT 16 C o m p a ra to r
Sc a le r
Sc a le r 2
System
bus
1
HVM o d ula to r
HVM o d ula to r
HV OFF
HV ON
Measure = fout (HV OFF) – fout (HV ON)
WTM
internal view
Sensor and HV modulation connections
RS 232 and T sensor connections
WTM
Control
panel
Parameter
setting
section
Output
section