IEC 61227 pdf – Nuclear power plants – Control rooms – Operator controls1Scope
This International Standard supplements IEC 60964 which applies to the design for controlrooms of nuclear power plants. it identifies the Human-Machine Interface (HMI)requirementsfor discrete controls，multiplexed conventional systems, and soft control systems. For the
main control room of a nuclear power plant,IEC 60964 includes general requirements forlayout,user needs and verification and validation methods,and these aspects are not
repeated in this standard.However,IEC 61772 on Visual Displays Unit (VDU) also provides
some guidance on displays and indications where necessary for the correct application of thecontrol requirements.
This standard is intended for application to the design of new main control rooms in nuclearpower plants designed to lEC 60964 where this is initiated after the publication of thisstandard. If it is desired to apply it to supplementary control points or local control positions,or to existing control rooms or designs，special caution shall be exercised as it makesassumptions such as the automation level that may not apply.
The following referenced documents are indispensable for the application of this document.For dated references, only the edition cited applies.For undated references, the latest editionof the referenced document (including any amendments) applies.
IEC 60073,Basic and safety principles for man-machine interface,marking and identification- Coding principles for indicators and actuators
IEc 60964,Nuclear power plants – Control rooms – Design of main control room
IEC 61771,Nuclear power plants – Control rooms – Verification and validation of designIEC 61772,Nuclear power plants – Control rooms – Application of visual display units (vDu)IAEA Safety guide NS-G-1.3:2002,Instrumentation and Control Systems lmportant to Safetyin Nuclear Power Plants
3 Terms and definitions
For the purposes of this document,the terms and definitions given in IEC 60964 and thefollowing definitions apply:
discrepancy control and indication
binary control with state and discrepancy indication using a single control switch
discrete (individual) controls
devices to support operator control of plant components,such as pumps， valves,controllers,with one control being assigned to a single plant component or function
used for several purposes at different times. For example, a start-stop switch may be selectedby another device associated to a number of plant items and used to start or stop the item towhich it is connected at the time
devices which the operator uses to send demand signals to control systems and plant items
electrically driven mechanical device which displays the plant condition (e.g. open or closedswitch position) by the angular position of the visible surface
control device for input of operator commands，that has connections with the control systemthat are mediated by software rather then direct physical connections. As a result,thefunctions of a soft control may be variable and context dependent rather than staticallydefined.
NOTETypically，soft control devices use VDUs for displaying the input options，and pointing devices such astrack ball,mouse, touch capability, or light pen for the selection of the choice.
soft control which uses a position detector to detect the operators finger pointing at the labelon the vDu (Visual Display Unit).Alternatively, a light pen may be used or a cursor may bemoved over the VDu format to identify a label. The label may describe an item of plant or acontrol action.
An overall systems design approach is required for the design of the HMI.IEC 60964 statesthe requirements for overall design of the control room system and the establishment of theprinciples required for safety, availability and user considerations, and the functional design ofthe system as a whole. The designer shall consider his goals,and the relative importance ofthe various design factors for his particular application.
Operator controls shall be designed so that operators can perform their tasks easily andcorrectly.Consideration shall be given to controi-display integration and the type of operatingprocedure and its presentation shall be taken into account in the choice of controls to beused. Particular attention shall be given to the needs of the operator for simple error-proofsystems that will optimize the operator’s performance under all conditions.Their design shallbe based on ergonomic principles to ensure ease of operation and to minimize operators’errors, both of omission and execution. Where conventional systems are used,mechanicalcharacteristics of control elements，such as size,operating pressure or force,tactilefeedback,etc.， shall meet human capabilities and characteristics specified in theanthropometric data base.