Liebert Universal Monitor - Manual (Page 35)

Wiring and Connections - Optional Expansion Board
27
5.2.2 Connecting Digital Outputs
The eight digital outputs are found at the top of the Expansion Board, as shown below. These inputs
are numbered 9 through 16. (Note that the digital outputs on the main board of the Universal Monitor
are numbered 1 - 8.)
Each output may be wired according to whether you want the output to be Normally Open or Nor-
mally Closed. The Expansion Board outputs are Form C relay contacts, each with three terminals.
There are two ways to wire the outputs, as shown in Figure 11.
• One wire of the two-wire connection should always be connected to the middle terminal.
• The second wire may be connected to either the N.C. terminal or the N.O. terminal, depending on
how whether you want the contact to be closed or open during a power failure:
• Connect to the N.C. terminal if you want the path to be CLOSED during a power failure, or
• Connect to the N.O. terminal if you want the path to be OPEN during a power failure.
Your choice for wiring the output contacts also determines how to set the fail-safe DIP switches for
proper operation (see 5.2.3 - Setting the Digital Output DIP Switches).
Figure 11 Form C output contact wiring
To connect an output:
1. Disconnect electrical power from the Expansion Board.
2. If necessary, remove a conduit knockout to permit wire entry into the Expansion Board enclosure.
3. Bring the wire(s) into the Expansion Board enclosure through a conduit knockout or access slot.
4. Loosen the appropriate screw and slip the stripped end of the wire into the terminal block.
5. Tighten the screw until it holds the wire snugly.
!
WARNING
“RISK OF ELECTRIC SHOCK” - Hazardous voltage may be present. More than one
disconnect switch may be required to de-energize the equipment before servicing.
!
CAUTION
The Expansion Board is designed for use on properly grounded (earthed) 24VAC Class 2
power, 50Hz or 60Hz. The ground wire for the power lead must be wired to the earth ground
terminal (stud located next to the 24VAC terminal block). This equipment is intended to be
installed by a qualified and certified electrician who must review and approve customer-
supplied wiring and circuit breakers, verify correct input and grounded (earthed) connections
to ensure compliance with technical standards and national and local electrical codes.
Segregate and install separate electrical conduits for non-class 2 circuits in accordance with
local building codes.
V2 V4 V6 V8 V10 V12 V14 V16
Multiflex
1
810-306
5
USE COPPER (CU) CONDUCTORS ONLY.
D6
POWER INPUT RELAY OUTPUTS
Numbering
keys
OUTPUT TERMINAL BLOCKS - Note numbering keys above terminal blocks;
outputs are numbered from left (9) to right (16)
N.C. N.O.
Wire connected
to N.C. terminal:
Relay is CLOSED
on power failure
N.C. N.O.
Wire connected
to N.O. terminal:
Relay is OPEN
on power failure
One wire MUST
be connected to
middle terminal