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3–8 MULTILINK ML1200 MANAGED FIELD SWITCH – INSTRUCTION MANUAL
INSTALLATION CHAPTER 3: INSTALLATION
3.4 Electrical Installation
3.4.1 Powering the Multilink ML1200 Managed Field Switch
The DC internal power supply supports installation environments where the DC voltage is
from 18 to 150 volts depending on the model selected. The power consumption will range
from about 20 up to 35 watts, depending on the port quantity and types in the
configuration.. When connecting the Ethernet cabling, there is no need to power down the
unit. Individual cable segments can be connected or disconnected without concern for
power-related problems or damage to the unit.
Power input options are available to suit the ML1200 Switches to special high-availability
communications and/or heavy industrial-grade applications, including:
• -48VDC, 24VDC and 125VDC with single DC input,
• -48VDC, 24VDC and 125VDC with dual-source DC input
External AC power supplies are optional, see Section 1.2, Ordering Information.
See the Appendices of this manual for more details. Use an RFQ for other variations.
3.4.2 Alarm Contacts for monitoring internal power, and Software Traps
The Alarm Contacts feature, standard on Multilink ML1200’s, provides two Form C Normally
Closed (NC) contacts to which the user can attach two sets of status monitoring wires at
the green terminal block. When this option is present, the terminal block for Alarm
Contacts is part of the Power Input panel in the ML1200 case. The DC power input
connection is in the same panel.
The first NC Alarm Contact (top position, switch vertically mounted) is a “Software Alarm”,
operated by user settings in the management software. The user can disable the Software
Alarm feature with a software configuration command if desired. When the Software
Alarm is enabled, the Form C Normally Closed (NC) contact is held close during normal
software operation. A user-defined software malfunction, such as an SNMP Trap or a
Software Security violation or an Ring-Only Mode Fault, causes the contact to open and
thus triggers an alarm in the user’s monitoring system
The second NC Alarm Contact is held closed when there is power on the main board inside
of the Switch. This provides a “Hardware Alarm” because the NC contacts will open when
internal power is lost, either from an external power down condition or by the failure of the
power supply inside of the Multilink Switch.
Useful information about Alarm contacts:
1. There are four terminal blocks (1,2,3,4) provided next to the DC power supply.
2. The top two pins (1,2) are software operated.
3. The bottom two pins (3,4) are hardware operated.
4. These are both NC (normally closed) relays.
5. The switch’s software operation needs to be enabled and set to get the Alarm
traps. For detailed information about the Software Alarm and software control
of SNMP alarm traps, please refer to chapter 5 of this manual.