10
2 TRANS(DUCER) TESTER
If you suspect the transducer has a problem, firstly disconnect it from the
echo sounder. Connect the transducer to the SIM990 with transducer tester
cable. Then run a sweep across the expected resonance frequency. Look at
the resonant frequency, the impedance and check it against the
manufacturers
’ specification. Generally, if the resonance frequency is within
5% of the designed frequency or the impedance is between 20 and 350 ohms,
the transducer is ok.
The transducer should be submerged into water when testing. Both
resonance frequency and impedance may change in air.
The tester is designed to sweep through a series of frequencies and measure
the characteristics of the transducer. Like a bell that rings at a particular
(resonant) frequency, most transducers have a frequency where they
perform best. For optimal use of the transducer, this frequency should be the
same, or close to the frequency that the echo sounder is sending. The tester
will measure the impedance as a factor of magnitude and phase through the
defined frequency range and find the point where these are lowest, defining
this as the resonant point.
Transducer should be
submerged into water!
