Page 513 - IRSEM_Main Book

(f) All Emergency operations shall be two-step process protected against
unintended operations.

(g) Only non-resettable counters shall be provided while working with Control
Panel or Control Terminal.

(h) Control Terminal shall have provision for Signal, Point and Line Block
Collars equivalent of Control Panel in the form of individual ‘Block’ & ‘Un-
Block’ feature which shall remain effective even during changeover from
one Control Terminal to other Control Terminal. ‘All Un Block’ option shall
be provided while E.I starts up to un-block all signals, points & lines after a
time delay of at least 120 seconds. SM’s key shall be required for
unblocking of a function whereas no SM’s key required for blocking. There
should not be any automatic unblocking of functions. Blocking of a function
shall be indicated on Control Terminal by different mark or colour over the
concerned function.
(i) Where Control Panel and Control Terminal are provided, it shall be
possible to switchover the controls from Control Panel to Control Terminal
and vice-versa, and where two Control Terminals are provided, it shall be
possible to switch the controls from one Control Terminal to other Control
Terminal through suitable means by either manual switch or password.

(j) Indication that E.I system is healthy shall be displayed on the Control Panel
using a blinking green LED or blinking green indicator on Control Terminal.
(k) Operation of points shall be possible only, when the interlocking is free
and relevant point track circuit is clear. Emergency operations provided
when point zone track circuit fails and after line verification from site by
traffic personnel, it shall be possible to operate the concerned point by
inserting an emergency key in a separate box provided interlocking is free.
Each such operation shall be recorded on a non-resettable counter.

(l) Each ‘Normal’ or ‘Reverse’ operation of point shall be controlled through two
output relays derived from two output bits should be from different output cards
of E.I.

(m) Last controlled position of points shall be available by using latch relay in
point control circuits.

(n) Mid stroke point reversal preventing feature shall be provided to prevent
starting of operation when the point is under operation or tried for other
position during mid stroke.

(o) When embedded block working in Electronic Interlocking is used, all
indications like TGT, TCF, LC etc required for block working shall also be
displayed

21.4.3 Interface with Electronic Interlocking
(a) Interface between Control Panel, Video Display Unit and Electronic
Interlocking system shall be of approved type.

(b) Interface of Points, Signals, Track Circuits and Controls such as Crank
Handle, LC Gate, Siding, Slot etc., with Electronic Interlocking System
shall be through Relays of approved type or through any Electronic
Modules of approved type conforming to approved specification. Interface
with E.I of adjacent station, Digital axle counter shall be of approved type.

Chapter 21: Relay & Electronic Interlocking Page 456 of 535