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

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(ii) There shall be two data-logging printers one on-line and the other as
standby. Both the printers shall be connected to the same on-line computer system. In
case of one printer, the other printer shall automatically take over.
(iii) In case of failure of one computer system, the switchover to the other
computer system shall be through an automatic switchover system. However, provision
for manual changeover between the computers shall be provided by the manufacturer.
6.1.2 Man Machine Interface
6.1.2.1 Workstations
6.1.2.1.1 There shall be two work-stations, one for each of two operators, each
consisting of two semigraphic colour VDU‘s and their keyboards. The keyboard shall
contain both functional keys for operations that are repeated frequently, and alphanumeric
keys for inputting numerical data and text. The key-board shall be interactive
with the displays on the VDUs, which allows parameter changes and device control by
identification of the object to be addressed by device or position reference input or via the
function and alphanumeric keys, or by the positioning of a cursor. The interaction
between the operator and the computer to select displays, to between the operator and the
computer system to select displays, to give commands, and to input data for limits,
calculation parameters and other items shall be of a simple dialogue nature. Text, for
tagging or recording or sanctions. May be temporarily added to the displays when entered
via the keyboard.
6.1.2.1.2 Both the workstation shall be connected to the same online computer and
shall meet the following requirements:
(i) Each workstation shall normally control pre-defined, physically demarcated
sections.
(ii) In case of complete outage of one workstation, all its functions shall be
transferred to the healthy workstation so that normal operations continue.
(iii) Normally one VDU will be online and the other VDU as standby at each of
the workstations. However, if desired by the operator, it shall be possible to have online
both the VDUs for viewing station diagram for tele control purpose and the other VDU
for viewing alarms, on-demand trend curves, histograms and other data.
Note:- Two workstations as mentioned above are for controlling upto 30
RTUs. However, if the number of RTU‘s in the system are less than or equal to 15 then
only one workstation shall be provided. On the other hand, if the number of RTUs in the
system are more than 30, then for each 15(or less) additional RTUs one more workstation
shall be provided.