Alstom GEM80-500 Series, Техническое руководство

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GEM80-500 Series Controller 6. Installation and Commissioning
(08/04) GEM80-500 Technical Manual (T2025En) Page 6-13
6.10 Watchdog Relay Connections
As a safety measure, the GEM80-500 Controller contains two Watchdog Relays with
normally open contacts.
These normally open contacts are wired in series and connected to the Watchdog
Socket Connector on the Controller front panel. A typical Watchdog Circuit is shown at
Figure 6-7.
When the system is running normally and in a healthy condition, the Watchdog Relays
are energised and the contacts closed.
When the system is tripped, either by the user program, or the self-testing detecting a
fault, the Watchdog Relays are de-energised and the contacts open.
The relays are also de-energised if the controller is Halted.
The Watchdog Relay contacts can therefore be used, usually in conjunction with a
follower relay, to interrupt the plant supplies in the event of the controller being halted
or tripped when a fault condition is detected.
The Watchdog Connector simply provides either an open or short circuit connection
between its pins depending on the controller condition.
Proceed to wire up the Watchdog connections as follows:
(a) Use the 2 metre long, two core cable rated at 250V, 1A, fitted with a moulded
“Figure of 8" socket supplied with the controller (referenced 56940/138) to mate
with the Watchdog Connector plug on the controller front panel;
(b) The free end of the cable may be connected into the system safety circuit as
required;
(c) Restrain the Watchdog cable as close as possible to the controller to prevent the
Watchdog Connector from being inadvertently disconnected.
WARNING
DO NOT apply a supply voltage directly across the pins of the Watchdog
Connector, or exceed the rated 1A load, otherwise the Watchdog Relay
contacts will be severely damaged.