Acoustic control during Timer Measurement Timer measurement
If the measurement value changes for the first time from the overflow (>1.999 GΩ) to a value
< 2.000 GΩ, a brief signal sound is audible as confirmation for having connected a UUT. If the
insulation resistance falls below the pre-set limit value, an additional signal (continuous signal)
is audible, whereby the signal level is clearly different from the first signal sound. Thus, it is
possible to test the insulation of several current circuits. The ISO-PRO is connected to a
protective conductor via a cable. The second cable will be equipped with a test probe. Test
voltage and Timer duration will be set. The limit value will be selected. Then, the
measurement is started pressing the Start key. The user hears a brief acoustic sound when
connecting the test probe to a current circuit. During the measurement of the subsequent
current circuit, a further brief signal sound is audible, etc. If the insulation resistance of a
current circuit is too low, the user hears a continuous sound during the time, the test probe
is measuring the faulty current circuit.
• If no brief signal sound is audible during the measurement of a current circuit, either the
timer duration has already elapsed, or the measurement value amounts to > 1.999 GΩ, or
the measurement instrument has not yet displayed the overflow between two
measurements.
• The last measurement value remains displayed until a new measurement procedure is
started or a different measurement range is selected.
Limit Value (LIMIT)
Repeated pressing of the "LIMIT" key (16) allows the setting of 3 limit values for the
insulation measurement, or to switch off the limit value monitoring.
The set limit value is displayed. If the measurement value falls below a pre-set value, a
warning signal is audible and the respective symbol is displayed.
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