Specifications

5.5). The display shall not be closer [o any observer than 1/2the display width or height, whichever is
greater.
5.2.5.4 Physical internmtion of view. Large screen displays shall not be located with respect to
critical observers so that the view of the display is obscured regularly by persons moving in normal
traffic patterns.
5.2.5.5 Control of displayed information, Control of Iarge-scnxn group display systems shall
ensure that critical information cannot be modified or deleted inadvertently or arbitrarily. Changes in
the group display shall be controlled by designated operators who operate according to pre-established
procedures, command of a person in charge, or both. When an individual must make changes that are
of interest only to him or her, a separate, remote display shall be provided.
5.2.5.6 Content of disdaved information. The content of displayed information shall be evident
to a trained observer without requiring reference to display control settings.
5.2.6 Other displaw.
5.2.6.1 General
5.2.6.1.1 TYpes, When apphcable, direct-reading counters, printers, plotters, flags, optical
projection, LED, gas discharge, liquid crystal and electroluminescent displays may be used.
5.2.6.1.2 Applications. The selection of the above types of displays for various applications
should be based on the following criteria as well as the criteria in Table LH.
5.2.6.2 Counters.
5.2.6.2.1 ~. Counters should be used to present quantitative data when a continuous trend
indication is not required and when a quick, precise indication is required.
5.2.6.2.2 Mounting. Counters shall be mounted as close as possible to the panel surface to
minimize parallax and shadows and maximize
the viewing angle.
5.2.6.2.3 SPacin~ between numerals. The horizonta! separation between numerals shall be
between one-quarter and one-half the numeral width. Commas shall not be used.
5.2.6.2.4 Movement.
a. Snap action. Numbers shall change by snap action in preference to continuous movement.
b. we Numbers shall follow each other
not faster than 2 per second when the observer is
expected to - then* consecutively.
c. Direction, The rotation of the counter reset knob shall &clockwise to increase the counter
indication or to reset the counter.
d. Reset. Counters used to indicate the sequencing of equipment shall be designed to be WW[
titIk HIMtiLdly upn completion d he queltct’. Pmvisiw) 4MII til~) I* II)* fol Iliwmtd ltx5iillIg
Wherr pllshlw!ttons tire LIse(l to mtin[lHllv rwet mechtinical counten. ac(ualing force rcquirtxl shall Iw
not more than 16.7 N (60 OZ).