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Page 232 MultiRanger 100/200 – INSTRUCTION MANUAL 7ML19981FB05
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App
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ndix C:
Tr
oubleshoot
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Noise Problems
Incorrect readings can be the result of noise problems, either acoustic or electrical, in the
application.
The noise present at the input to the ultrasonic receiver can be determined by viewing
parameter P807. The display reads ##:##, where the first number is the average noise and
the second is the peak noise. In general, the most useful value is the average noise.
With no transducer attached the noise is under 5 dB. This is often called the noise floor. If
the value with a transducer attached is greater than 5 dB, then signal processing
problems can occur. High noise decreases the maximum distance that can be measured.
The exact relationship between noise and maximum distance is dependent on the
transducer type and the material being measured. Any average noise level greater than
20 dB is probably cause for concern unless the distance is much shorter than the
maximum for the transducer.
Determine the Noise Source
Disconnect the transducer from the MultiRanger. If the measured noise is below 5 dB,
then continue here. If the measured noise is above 5 dB go to
Non-Transducer Noise
Sources
below.
1. Connect only the shield wire of the transducer to the MultiRanger. If the measured
noise is below 5 dB, continue with the next step. If the noise is above 5 dB, go to
Common Wiring Problems.
2. Connect the white and black transducer wires to the MultiRanger. Record the
average noise.
3. Remove the positive wire of the transducer. Record the average noise.
4. Re-connect the positive wire and remove the negative wire. Record the average
noise.
Using the table below, determine the appropriate next step. The terms higher, lower and
unchanged refer to the noise recorded in the previous steps.
These are guidelines only. If the suggested solution does not solve the problem, try the
other options also.
Acoustical Noise
To confirm that the problem is acoustical, place several layers of cardboard over the face
of the transducer. If the noise is reduced, the noise is definitely acoustical.
- removed + removed Go to:
no
ise
higher
higher Reducing Electrical Noise
unchanged Common Wiring Problems
lower Reducing Acoustical Noise
unchanged
higher Reducing Electrical Noise
unchanged Contact Siemens Milltronics
lower Reducing Acoustical Noise
lower
higher Common Wiring Problems
unchanged Common Wiring Problems
lower Reducing Acoustical Noise