Sigma ONYX EASY Mode D'emploi page 58

Why does the display react slowly or is coloured black?
The operating temperature may be too high or low. Your heart rate monitor
is designed for temperatures between 0 °C and 55 °C
(32 - 140 degrees F).
What should I do if the screen display is weak?
A weak display may be due to weak batteries. You should change them as
quickly as possible – battery type CR 2032 (Item No. 00342)
PAGE 26
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7.3 Beep
summary
The ONYX EASY
provides information
with various beep
signals.
The different volume settings are:
1 x long: 3 x short in interval:
When entering Zone Countdown has finished,
alarm rings
3 x short:
If you are below Zone 1 x short:
Button beep
5 x short:
When you are above Zone