| 摘要 |
PURPOSE:To reduce the number of workers for calibration to one, by a method wherein a gas concn. indicator is provided with a means to maintain the max. value of the concn. of a gas, then, a worker blows a reference density of gas to a gas sensor at a remote point and returns to a main unit. CONSTITUTION:When a maintenance switch SWm is turned ON, a timer T1 is switched ON after a set time and a relay RY1 starts to work, which causes a contact RY1a to be switched over to a main amplifier MA through a peak holding circuit pH from a preamplifier PA to maintain the max. value of an output of a gas sensor S. A self-holding circuit SH is kept ready for alarming even when a line R is ON as a contact RY1b is turned OFF. With such an arrangement, a worker moves to apply a reference gas all the way to a gas sensor S located away from an alarm body and, then, returns to the main unit side of a gas detector to check an indication of an indicator unit 10. Afterward, the calibration of a gas concn. indicator M is performed.
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