Specifications

X723-300151 2-5 Issue 2
2.2.3 Power Connections and Earth Bonding
The 3200 should be wired to the power shelf using the flying lead
protruding from the rear of the unit. This lead will connect directly to the
socket situated on the rear of the power supply shelf. The power supply
shelf may be situated above or below the 3200.
Earth Bonding
Correct earth bonding of the chassis is important if the equipment is not
to be affected by electrostatic discharge (ESD) or other environmental
interference sources. A separate earth connection must be made from the
chassis earth stud to the station earthing system. The resistance of this
connection must not exceed 0.03 ohms which should be checked using an
earth bonding tester. Note that if the earthing arrangements are via a
rack earth bar or rack framework, the total earth resistance must not
exceed that stated above.
2.2.4 Alarm and Control Wiring
The alarm outputs, control outputs and external status inputs are
accessed via a 37 way 'D' Type connector. The alarm and control output
change over contacts are isolated. The N/C and COM contacts should be
used to provide a short circuit loop during alarm conditions. See Table 2-1.
An alarm is active when the relays are de-energised, hence when power is
removed from the unit all alarms become active.
The external status inputs are '0V sensing' and designed to operate with
TTL level inputs. 0V is the alarm condition with +5V or open circuit being
the non alarm state. See alarm specifications in section 1.
External status lines 2 to 6 may be connected to co-located equipment to
monitor, for example, alarm relay status. The external relay contacts may
be wired to control external equipment.
Observe BS6301 safety requirements when making any external
connections.