Instructions

When the PORT setting is ON, the alarm port outputs an electrical signal to in
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dicate that an alarm event has occurred. Under normal conditions the output
will be 0V. When an alarm event occurs, and PORT is ON, the output will be
driven at approximately 12V DC. The output remains active until alarms are re
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set (see Section 7.4.4, Alarm View). The alarm port is disabled while operating
on internal battery power.
The alarm port may be connected to external indicator devices. The jack ac
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cepts a 2.5 mm two-conductor subminiature plug (Switchcraft #850). The
sleeve of the plug is ground and the tip is positive. The port can source up to 20
mA of current.
As part of the start-up self-test performed when the instrument is switched on,
the alarm port is briefly activated for approximately 50 ms (regardless of the
PORT setting). This ensures that the alarm port is functioning.
The ud buttons are used to select the menu option. The lr buttons are
used to change the parameter setting. Press the Enter buttontosavethenew
setting. Press the Exit button to cancel any changes and exit to the menu.
7.4.2 Sensor Alarm
The SENSOR ALARM function enables various sensor-related alarms. For en
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abled sensor alarm events to be indicated, an indicator must be enabled with
ALARM SETTING as described above.
1620A “DewK” Thermo-hygrometer
User’s Guide
52
Figure 35 Alarm Setting