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Chapter 3Settings
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Chattering
Filter set to ON
8. Filter setting
The filter setting can be made when the 3639-20, the 3911-
20, and the PC are interconnected. Either "Mechanical-
contact input" or "Electronic-contact input" can be selected
for the filter. Default setting is Mechanical-contact input.
In the case of the mechanical contacts of a relay or switch,
noise referred to as "chattering" may be heard when signals
are switched over. When the filter is set to "Mechanical-
contact input," noise components such as those of the
mechanical-contact chattering can be eliminated (see the
figure). If "Electronic-contact input" is selected, the
chattering cannot be eliminated. In the case illustrated
below, the measurement value will be 1 if "Mechanical-
contact input" is selected, or 5 if "Electronic-contact input"
is selected.
9. Alarm setting
The Alarm Setting can be made when the 3639-20, the
3911-20, and the PC are interconnected. Default setting is
the alarm output set to OFF.
The product issues an alarm signal if a measurement value
exceeds the preset upper-limit value. Decision of an alarm
and its output are made at each individual recording
interval. An alarm once issued will continue to be output
until the measurement value has fallen below the preset
upper-limit value (see the figure below). "AL" remains
displayed on the screen while the alarm signal is being
output.
