Page 487 - IRSEM_Main Book

Chapter 21: Relay & Electronic Interlocking

Section 1: Design Criteria of Signalling Circuits

21.1.1 Circuits - General
(a) The Detailed designs for circuits of interlocking may be required for;

(i) Route Setting Type i.e. on the basis of Entry/Exit principle.
(ii) Non-route Setting Type i.e. Route is set with individual operation of
points for existing installations or alterations.

(b) The designs shall be suitable for RE as per stipulations in Chapter 22 of
SEM on "Requirements of signalling in 25 KV AC electrified areas".
(c) The designs shall be in accordance with the approved signalling plans,
Control Table, Control Panel diagram, Relay contact analysis and relay
rack arrangements.

(d) The designs shall be suitable for the specific type equipment to be
installed such as Make of Electronic Interlocking (Distributed or Central),
MSDAC, SSDAC, UFSBI,Block Working built into Electronic Interlocking
etc and the type of Interfacing & features, they provide. Use of dual OFC
in Distributed type of Electronic Interlocking, are desirable as they reduce
extent of copper cables & provide an alternate path in case of Failures.

(e) The drawings & designs shall be made in accordance with Typical
templates, RDSO`s Standard circuits/templates, guidelines, Board
guidelines, Industry`s best practices & principles of Reliability, Availability,
Maintenance & Safety in mind.

21.1.2 Control Panels - General

(a) The display of the layout on the front of the Control Panel referred to as the
illuminated diagram shall be well proportioned. Where additional facilities are
likely to be provided, domino type panel shall, preferably be used. The areas
covered by each track circuit shall be clearly distinguished by use of different
colours.

(b) The operating members, namely route switches/buttons, point switches etc.,
referred to in the following clauses shall normally be provided on the
illuminated diagram itself in Geographical order. A separate illuminated
diagram for indication and a separate 'console' containing all the operating
members may also be provided.

(c) At Non-route setting type installations, the route may be set with
individual operation of points.

(d) The Route setting shall be on "Entry/Exit" principle for installations of
Route Setting type. Each route shall be controlled by means of two push
buttons - one at the entrance and the other at the exit of the route.

Chapter 21: Relay & Electronic Interlocking Page 433 of 535