Yokogawa IR400 - Manual (Page 65)

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IM 11G02N01-01E
If CO concentration exceeds the alarm value, counting will begin. If the number of peaks is over
the set times per hour, a peak alarm contact output becomes closed (ON). If it is less than the set
times per hour, it is open (OFF). Since 5 times of peaks /hour is marked at (1) section from
the above graph, the peak count alarm is turned ON. Since peaks of more than 5 times per 1 hour
occur at the interval between (1) and (2) , the peak count alarm remains ON. Since at (2),
peaks are reduced to 4 times per hour, it is turned OFF.
Like the hysteresis of the alarm setting , the hysteresis prevents possible chattering when
measured gas is fluctuated near the alarm value.
* For 10 minutes after the power is turned ON, a peak alarm counting is not carried out.
Releasing peak count alarm
To release the peak count alarm, set the peak alarm to OFF.
Turning on the peak alarm initiates counting from 0.
Action of peak alarm
Example
[% full scale] represents the percentage with the CO range regarded as 100%.
Setting range
Alarm value : 10 to 1000 ppm 5 ppm step (initial value: 500 ppm)
Alarm count : 1 to 99 times (initial value: 5 times)
Hysteresis : 0 to 20 % of full scale (initial value: 0% of full scale)