The control, display, and recording functions of any system constitute the major portion of the instrumentation Man is linked to the machine by the displays and controls, and he uses the recorded data to analyze and improve operation.

10-6.1 Control—Display Relation

Proper relation of the control function to the display is the basic purpose of the system. The function of the display system is to provide information to enable the operations personnel to make decisions regarding plant and system operation. The grouping of control—display com­ponents should always reflect the use of human factors engineering The maximum efficiency with which data can be perceived and the control action initiated indicates the effectiveness of the control—display design

10-6.2 Installation of Hand Controls

The installation of hand controls should utilize human — factors engineering Considerable thought must be given to aspects such as type and placement of controls as related to function Likewise, operator qualifications and limitations should be considered. All controls should be mounted to withstand the rigors of normal use and possible abuse Controls affecting plant or system safety should be pro­tected from accidental actuation Controls that are subject to extreme environments should be protected, including the marking and identification of the control.

10-6.3 Installation of Specific Controls

Nuclear reactor instrumentation systems use some specific controls that are unique, not necessarily in the components used, but rather with application and interac­tions of the controls When components are being selected, the function of components being controlled as well as the function of the controlling component should be consid­ered. Such components as push buttons, selector switches, and level switches have specific applications Factors such as speed of response and resolution of control should also be considered in selecting specific components. Control for such components as control and safety rods should be selected and installed in the prime control areas of the main control console, with primary and secondary loop and auxiliary controls being installed according to frequency of use and importance to the system.

10-6.4 Installation of Visual Display and Recording Equipment

The location of all equipment that must be visually monitored should be given priority consideration. The physical abilities and limitations, as well as the psychologi­cal characteristics, of the operating personnel should be taken into account Viewing distance and angle as well as illumination must be considered, along with character size, configuration, and background, to avoid eye strain, inaccu­rate perception, and glare Audible display should be considered in areas where there is a possibility of failure to give the necessary visual cognizance for critical and semi — cntical parameters

Compatibility with related controls and possible percep­tual interaction with other displayed information are important factors in the installation of effective displays Recording equipment also used for displaying information should adhere to the criteria for any display equipment. In addition, recording equipment must be installed so that routine operational maintenance, such as inking and chart — paper replacement, can be accomplished with maximum efficiency

10-6.5 Installation Recommendations

The installation of an instrumentation system involves the use of a combination of practices to achieve the desired results, both from a functional and an aesthetic standpoint (see Fig 10.25) Instruments and components should be grouped and mounted so that they are aesthetically neat and orderly as well as logically functional. Instruments with varying front panel dimensions should be mounted so that the instrument case tops are level Switches and pilot lights should be mounted with the center lines even Instruments with hinged doors should be mounted so that there is no interference between adjacent instruments. In general,

controls, displays, and recorders should be placed in the prime functional areas of the panels in which they are mounted. Components that require visual readout should be as close as possible to eye level. All control actuation components should be kept within easy reach (at least 18 in. above floor level).