SPECICATION NO. ETI/PSI/144 (12/91) SPECIFICATION FOR ... - rdso

an authorized person without any previous knowledge of programming language to carry
out the necessary amendments.
(ii) Facilities shall be provided for the operator, through simple
keyboard commands to:
-take out of scan and control (process inhibit) any alarm
point/control point/measured or a complete RTU.
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-block/de-block a complete RTU as well as any control point
(circuit breaker, interruptor and other equipments at the controlled station) which
disables/enables control operations from the RCC. The blocked condition of any
equipment shall be suitably indicated on the VDU, for example by a change in colour of
the corresponding equipment display.
-inhibit any alarm point which shall discontinue processing of the
alarm point at the RCC.
(iii) The software shall be designed for maximum portability and
upgradability, so that it is generally machine independent and upgradable to meet with
the developments in the computer hardware/technology.
6.1.4.4.4 The software should support BROADCAST control, i.e. sequential
commands to a group of equipments like circuit breakers, interruptors.
6.1.4.4.5 Transmission and coding system
The master station equipment shall normally scan continuosly all the
RTUs in a pre-defined cyclic sequence, to update the equipment status, alarms, events
and measurands. Exchange of information between the master station and the RTUs shall
be on interrogation by the master followed by the reply from the RTU. The
communication technique shall be based on Digital Address Time Division Multiplexing.
Every data-exchange shall be based on a well defined transmission protocol based on
International Standard for data transmission. Each transmitted information shall contain
sufficient parity check bits so as to allow an effective error detection code to detect
different combination of transmission errors. The error checking system shall have a
minimum Hamming distance of four i.e. all three bit errors shall be detected one hundred
percent.
6.1.4.4.6 Communication pr optical
The communication protocol employed in the system, including transmission security
and computation of reliability factor, shall be clearly explained in the offer. The tenderer