PureAire Monitoring Systems, Inc.
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5.5.8 Set Alarm Hysteresis
PureAire’s
CO
2
monitor may be used as a control system. When used to regulate
carbon dioxide levels the need of a dead band, “hysteresis” may be required for the
alarm relays. This menu will permit the setting of the alarm hysteresis to a desired
concentration of Carbon Dioxide. When using hysteresis, the alarm set point now
becomes an average alarm setting for an action to occur. When adding the hysteresis
value to the alarm set point, this then defines the alarm and dead band for an action to
occur.
For example, if you require a valve to close at 5,000ppm level and to reopen again at
5,050 ppm, you will set the Alarm Threshold at 5000ppm and set the hysteresis value at
50ppm.
Average Alarm set point = 5,000 set the Hysteresis to 50ppm= Valve Off (5,050ppm)
To access this menu, push the joystick down to display the
Set Alarm Hysteresis
menu. This will scroll on the digital display.
Push the joystick right to access the
Set Alarm 1, CO2, Hysteresis
.
It will display a value 00 PPM, (factory default). Pushing the joystick up increases the
CO
2
PPM up to a maximum value of 1000 PPM. Adjust the digital display until the
desired hysteresis value is selected.
After entering the alarm setting push the joystick left to enter the setting. The display
will scroll the following:
..Set Alarm Hysteresis…
50 PPM
..Set Alarm 1, CO2, Hysteresis…
..Set Alarm 1, CO2, Hysteresis…
