ECOTEST DKG-21 M Operating Manual page 70

If during operation of the dosimeter DER exceeded
the upper limit of the measurement range, the measured
DE value may be incorrect (too low). In this case, a
blinking decimal point in the mode of DE measurement
indication may indicate to a possible incorrectness of
DE value.
4.3.3.5 Programming of audio and light DE alarm
threshold levels
Audio and light alarm threshold level of DE is
programmed in the mode of DE measurement
indication. Press the THRESHOLD button and hold it
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