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Overload and Under Range Conditions
Overload Condition
An overload condition occurs when the peak signal starts to exceed the signal
handling capability of the pre-amplifier circuitry. If the noise source exceeds the
linear operating range of the range selected by 0.5dB then an overload
condition occurs and an overload indicator is displayed on your meter.
At 1kHz the overload condition occurs at 0.5dB above the top of each range for
all frequency weightings. The overload indicator will flash for a minimum of one
second or while the overload condition remains.
In such circumstances it is highly recommended you change to a higher range
with a lower sensitivity (i.e. less gain) as your meter will be out of specification.
An overload indication can occur in both Stop or Record Mode on ‘L’ and ‘E’
models and only in Record Mode for models ‘I’ and ‘B’.
All models have an overload latch indicator which can be viewed by scrolling
through the available parameters. Depending on whether an overload has
occurred or not, the overload latch screen will display either off the following: -
On models ‘I’ and ‘B’ if an overload has been latched it can be removed in Stop
Mode or Record Mode by resetting the parameters.
On models ‘L’ and ‘E’ instruments a latched overload can be removed in Stop
Mode by resetting parameters and if in Record Mode it is automatically
removed when the recording has been stopped.
Please be aware that the selected frequency weighting may attenuate the
displayed signal level below the overload triggering point but an overload can still
occur. This is because the overload operates from the unweighted input signal.
Note: In most case, if you see an overload indication on your sound meter, you
should discard the measurements taken, select a higher range and re-take the
measurements.
OVERLOAD
O.L. NO
O.L. YES
