User's Manual

PMAC2 PCI Hardware Reference Manual
Base Board Connector Pinouts 37
TB2 (3-Pin Terminal Block)
This terminal block provides the output for PMAC2's watchdog timer relay, both normally open and
normally closed contacts.
Pin# Symbol Function Description Notes
1 WD_NC Output Watchdog relay out Normally closed
2 COM Input Watchdog return +V or 0V
3 WD_NO Output Watchdog relay out Normally open
Note: The normally closed relay contact is open while PMAC2 is operating properly — it has power and
the watchdog timer is not tripped. This contact is closed when the PMAC2 is not operating properly (either
the PMAC has lost power or the watchdog timer has tripped). The normally open relay contact is closed
while PMAC2 is operating properly, and open when PMAC2 is not operating properly.