Figure 5: Sample Output Alarm-Reporting Device; Mx104 Hardware Components; Table 5: Alarm Relay Contact Functions - Juniper MX104 Hardware Manual

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Closed [NC] through the CLI. Contact 2 of each alarm functions as a reference [REF] or
negative potential terminal for Contact 1 of the corresponding alarm and provides a
current path for external alarm devices.
the alarm contacts.

Table 5: Alarm Relay Contact Functions

Contact
Name Contact Name
Contact 1 Normally Open [NO]
Normally Closed [NC]
Contact 2 Reference [REF]
Figure 5 on page 13 shows an example of a wiring diagram for a simple output
alarm-reporting device. In this case, the device is a light bulb that illuminates when the
device encounters a condition that activates the red alarm LED and relay contacts. The
alarm relay contacts can also be used to activate other devices such as bells or buzzers.

Figure 5: Sample Output Alarm-Reporting Device

Figure 6 on page 14 shows an example of a wiring diagram for a simple input
alarm-reporting device. In this case, the push button switch is an alarm sensor that triggers
an input alarm when a door-open condition occurs.
Chapter 2: MX104 Hardware Components
Table 5 on page 13 describes the functions of
Function
Current is not flowing through Contact 1 and Contact 2
[REF] when operating normally. When the current flows,
the closed alarm is generated.
Current is flowing through Contact 1 and Contact 2 [REF]
when operating normally. When the current stops
flowing, the open alarm is generated.
Provides the current path for the external alarm-reporting
device and functions as a reference or negative potential
terminal for Contact 1.
13