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CO2 Alarm

Devices equipped with the CO2 sensor can monitor a CO2 concentration and alarm user in case of too high values. An alarm state is presented in the following parameter or in the iSMA Configurator:

ALARM_STATUS: indicates a current status of the CO2 alarm;

  • Modbus register: 30230;
  • BACnet object: BI0, property: Present Value.

The CO2 alarm can be configured using the following parameters:

CO2_SETPOINT_FOR_ALARM: allows to set a tipping point for CO2 alarm. The default value is set to 1500 ppm;

  • Modbus register: 40226;
  • BACnet object: AO19, property: Present Value;

CO2_HYSTERESIS_FOR_ALARM: allows to set a hysteresis value for launching the CO2 alarm. The default value is set to 100 ppm;

  • Modbus register: 40227;
  • BACnet object: AO20, property: Present Value.

User Interface for CO2 Alarm

When the alarm triggers (the ALARM_STATUS register's value is 1), it can be confirmed by pressing any touchscreen button. It stops a visualization of the alarm status, but does not affect the ALARM_STATUS parameter.

The alarm confirmation can be configured in the following parameter:

DEVICE_CONFIGURATION, bit 8: CO2_ALARM_CONFIRM: allows to enable confirmation of the CO2 alarm with any button of the panel;

  • Modbus register: 40205;
  • BACnet object: BO63, property: Present Value.

After the CO2 alarm triggers, the feature takes control over the display and illumination and starts blinking. The control is returned to normal after the alarm is confirmed or after the CO2 value decreases below the CO2_SETPOINT_FOR_ALARM level (taking the CO2_HYSTERESIS_FOR_ALARM value into account).

This feature is active by default and cannot by turned off. However, a user can decide if the alarm status should be visible through user interface:

DEVICE_CONFIGURATION, bit 5: CO2_ALARM_LCD: switches on the function of LCD background illumination flashing when the CO2 alarm occurs. If the bit 5 is true, the CO2 alarm is indicated by the LCD display flashing;

  • Modbus register: 40205;
  • BACnet object: BO5, property: Present Value;

DEVICE_CONFIGURATION, bit 6: CO2_ALARM_BUZZER: switches a buzzer on when the CO2 alarm occurs. If the bit 6 is true, the CO2 alarm is indicated by the buzzer, which emits sounds with 1 Hz frequency;

  • Modbus register: 40205;
  • BACnet object: BO6, property: Present Value.
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