Siemens 200 Noise Problems, Determine the Noise Source, Removed + removed Go to, Acoustical Noise

Appendix C: Troubleshooting

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.

	- removed	+ removed	Go to:
		higher	Reducing Electrical Noise
	higher	unchanged	Common Wiring Problems
		lower	Reducing Acoustical Noise
noise		higher	Reducing Electrical Noise
	unchanged	unchanged	Contact Siemens Milltronics
		lower	Reducing Acoustical Noise
		higher	Common Wiring Problems
	lower	unchanged	Common Wiring Problems
		lower	Reducing Acoustical Noise

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.

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