Electrical Connections—UPS
Liebert
®
eXM
™
32
3.4.5 EPO Input—Optional
NOTICE
Risk of exceeding internal voltage limits. Can cause equipment damage.
Do not apply more than 12V to the Emergency Power Off (EPO) input. Exceeding 12V on this
input can damage the Liebert eXM’s internal circuitry and control boards. Exceeding 12V will
also put the Liebert eXM in an EPO state, and the unit will not reset, making it non-
functional.
The UPS has an Emergency Power Off (EPO) function operated by a button on the control panel or by
a remote contact provided by the user. The EPO button is under a hinged, clear plastic shield.
The J2 connector, shown in Figure 18, is the remote EPO input interface. The EPO has NO/NC
contacts that become active when shorting terminals J2: 3 and 4 or open terminal connection J2:2
and 1.
If an external Emergency Stop capability is required, it is connected at terminals J2: 1 and 2 and at
J2: 3 and 4 on the monitor board. It also is connected to the Normally Open or Normally Closed
remote stop switch between these two terminals using shielded cable (see Figure 18 and Table 9). If
this function is not used, terminals J2:3 and 4 must be opened and J2:1 and 2 must be closed.
Figure 18 EPO wiring and signal names for J2
Table 9 EPO input contact relays—J2
Pin
Name Description
1 EPO-NC EPO activated when opened to Pin 2
2 + 12V EPO activated when opened to Pin 1
3 + 12V EPO activated when shorted to Pin 4
4 EPO-NO EPO activated when shorted to Pin 3
NOTE
The Emergency Stop action within the UPS shuts down the rectifier, inverter and static
bypass. It does not internally disconnect the input power supply. To disconnect ALL power to
the UPS, open the upstream feeder breaker(s) after the remote EPO is activated.
NOTE
Normally Closed EPO – J2: 12, these terminals are supplied factory-linked on the Bypass
Module on the UPS and must remain installed if using NO contacts.
NOTE
All auxiliary cables of terminal must be double-insulated. Wire should be 20-16AWG stranded
for maximum runs between 80 and 200 feet (25-60m), respectively.
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