Link-systems System 1100 Tonnage Monitor Manuel d'utilisateur télécharger pdf (Page 43)

THEORY OF OPERATION

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3-6

Figure 8. Harmonic Noise.

transducers when no load forces are being developed in the machine,

and may cause a small variation in displayed tonnage from stroke to

stroke for each channel as harmonic strain is added to load strain.

It should be noted, however, that the effects of harmonic vibration

are generally reduced when the machine actually exerts force in the

production process. Figure 7 illustrates harmonic "mechanical

noise" in a strip chart recording of a tonnage monitor output

signal.

3.4.2 Structural "Ringing"

Any elastic body has a natural response which dies out with time if

energy is suddenly applied to or removed from the body. Just as

a diving board vibrates back and forth in dying oscillations until

it is again stationary when suddenly relieved of a person's weight,

a machine structure "rings" when load is suddenly released by

material breakthrough in blanking and piercing operations. Figure

8 illustrates a typical ringing at the end of a blanking operation

in a tonnage monitor signal.

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Link-systems System 1100 Tonnage Monitor Manuel d'utilisateur Page 43