Adjusting Sensitivity - Elcometer Protovale 331 Operating Instructions Manual

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DJUSTING SENSITIVITY

8 ADJUSTING SENSITIVITY

The sensitivity setting is indicated by the variable wedge-
shaped symbol on the display. To increase the sensitivity,
press . To decrease the sensitivity, press .
Typically, set the sensitivity to produce a slow 'clicking' sound
in the absence of metal. With the sensitivity set at this level you will be able to
differentiate quickly between bars of the same size located at different depths.
If the sensitivity is optimised, the pitch of the sound will consistently give a good
guide to the extent of cover; shallower-than-average bars will produce a clearly
noticeable, more intense sound, which will draw your attention to such bars.
However, if the sensitivity has been adjusted to an arbitrary level, the necessary
degree of consistency may not be achieved.
To improve audible resolution when locating closely spaced reinforcement bars
it may be beneficial to reduce the sensitivity below the optimum level described
in the previous paragraphs.
It is also possible to reduce sensitivity deliberately so that bars of adequate
cover are not indicated, but bars of shallower cover are. Please note that this
method will not confirm the presence of bars with adequate or deeper cover.
During a search the sound from the speaker and the brightness of the LED may
reach their maximum level before the signal has reached its maximum. If this
occurs, reduce the sensitivity until the sound and LED are again responding
readily to changes.
Note: Reducing the sensitivity does not reduce the overall sensitivity of the
instrument, but will reduce the sound and LED indications to zero when the
search head is removed from the region of high signal strength. This may cause
deeply covered bars to be missed.
If the sensitivity is reduced to the minimum setting, the locate
sound is muted (indicated by a crossed-out loudspeaker
symbol on the screen).
The sensitivity setting only affects the locate sound and the
brightness of the LED on the search head; it does not affect the cover
measurement.
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