Teledyne 7500 - Infrared gas analyzer - operating manual - Manual (Page 52)

52 Model 7500 Instruction Manual
Teledyne Analytical Instruments
Setting range
• Alarm Value: 0 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)
* The hysteresis setting is made in terms of full scale.
Action of peak alarm
If CO concentration exceeds the alarm value, counting will begin. If the number of peaks is over the set
times per hour, a peak count alarm 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 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 alarm
To release the peak alarm, set the peak alarm to OFF.
Turning on the peak alarm initiates counting from 0.