Wired Combination CO/Smoke Detector Interface Modules
When it comes to hardwired combination carbon monoxide and smoke detectors, there are a lot of things to consider. Some are high-voltage devices that cannot interface directly with alarm systems. The only way to include these devices with a system is with a takeover module that actively listens for the temporal sound of a triggered life-safety sensor. An example of a takeover module is the Encore FireFighter FF345.
There are also hardwired life-safety sensors that use low-voltage power. These devices can usually be integrated with hardwired systems directly. This is usually done through a 2-wire or 4-wire connection. The advantage to using 2-wire sensors is that they can usually be automatically reset by the panel. However, they must be configured with a special Normally Open zone. For example, this is Zone 1 on the VISTA Series Panels.
For greater flexibility in selecting a zone, a user can opt for 4-wire life-safety sensors. These devices can be assigned to any hardwired zone. But they require additional equipment. For example, a 4-wire smoke detector will need an external relay for cutting power when alarms are cleared to reset the sensor. You may also need an external power supply to provide sufficient current to the sensor. And you will also need the appropriate end of line resistor (EOLR) wired-in as well.
But hardwired combination sensors become a little bit more complicated. This is because these devices actually need to connect with multiple system zones. More specifically, they need a zone for fire detection and another zone for CO detection. This way, the system knows which type of alarm has occurred. But it's not as simple as wiring the sensor to multiple zones. You need an interface module so that the system can properly differentiate between the two alarm types.
Most hardwired combination smoke and CO modules require an interface module. Our biggest example example is the System Sensor COSMO devices. The interface module will actually cut power to the sensors when an alarm is cleared. However, a relay and end-of-line power supervision module will still be required. Most interface modules can support multiple devices. For example, the System Sensor COSMOD2W can support up to 12 combination sensors.
An interface module will allow a single combination device to program with two separate zones. One zone will be used for CO detection, and the other will be used for fire detection. As this is an essential component for combination life-safety sensors, most hardwired combination sensors will require an interface module. Wireless combination sensors have things much easier, as they can just be assigned to multiple wireless zones using Loop Numbers or different Serial Numbers. Wireless combo sensors do not need an interface module.
If you are planning to add hardwired combination life-safety sensors, then it is likely that you will need one or more wired combination CO/smoke detector interface modules. You should check the specifications of the wired combination CO/Smoke detector interface modules to determine how many you need. Most setups will require only one. But a larger industrial or commercial application may require multiple interface modules.