STC SmartScanIS, Руководство пользователя

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EUD-2016026-00 Rev.2, SmartScanIS User’s Guide for Union Pacific, 14 January 2021
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Bearing temperatures are sampled for a short period before the gate opens, to support
detection of Pyrometer Saturation alarms, and while the gate is open
10.7.2 Referencing System
Pyrometers measure rapid changes in infrared energy emitted from objects passing through
their field of view. The rail-mounted scanners are aligned to take advantage of this
characteristic.
When no axle is present between the gating transducers, the scanner typically sees only the
undersides of the cars passing over the site. The undersides of the cars are at or near
ambient temperature, thus establishing the reference from which the elevated temperatures of
bearings are measured. The pyrometers normalize during this time, producing a zero level
signal.
Occasionally, the scanners are exposed to infrared emissions that are colder than the
underside of the cars. Typically, this occurs in the gaps between cars when the scanners may
reference on clear sky. This could present an erroneous reference if a bearing was scanned
immediately following a sky shot, resulting in an abnormally high reading for the bearing. The
pyrometers have internal circuitry to prevent the reference from shifting below the established
zero reference.