DVR Alarm Output Application

Maximum Time I wrote for Sales/ Marketing / Commercial professional, but this post dedicated to Technical services Technician / Engineers. Many engineers say's How to Connect DVR Alarm output with Power Source/ whats the application etc etc.

A DVR (Digital Video Recorder) alarm output application refers to the use of the alarm output capabilities of a DVR system to trigger external actions or notifications in response to certain events or conditions detected by the DVR. These applications enhance the functionality and usefulness of DVR systems in various security and surveillance scenarios. Here are some common uses of DVR alarm output applications:

1. Intrusion Detection: When a DVR detects motion or unauthorized entry in a secured area via connected surveillance cameras, it can trigger alarm outputs. These outputs can activate external alarms such as sirens, strobe lights, or even notify security personnel or authorities.
   
   
   Door Access Control: Some DVR systems are integrated with access control systems. When someone presents a valid access card or enters a PIN code, the DVR can send a signal to unlock a door or gate, granting access to an authorized individual.
   
   
   Smoke and Fire Detection: In situations where a DVR is part of a broader security and safety system, it can be connected to smoke detectors and fire alarms. When smoke or fire is detected, the DVR can trigger alarms, initiate evacuation procedures, and record video footage for investigative purposes.
   
   
   Perimeter Protection: For properties with fences or boundaries, outdoor surveillance cameras connected to a DVR can monitor the perimeter. If an intruder breaches the perimeter, the DVR can activate alarms or external lighting to deter the intruder.
   
   
   Temperature and Environmental Alerts: In some cases, DVR systems can monitor environmental conditions such as temperature or humidity. If conditions exceed predetermined thresholds (e.g., in server rooms or storage facilities), the DVR can send alerts or trigger alarms to prevent equipment damage.
   
   
   Emergency Notifications: DVR alarm outputs can be configured to send notifications to designated individuals or emergency response teams in case of critical events, ensuring a rapid response to security incidents.
   
   
   Integration with Other Systems: DVRs often support integration with other security and automation systems, including intrusion detection systems, access control systems, and building management systems. This integration allows for comprehensive security and automation applications.
   
   
   Remote Monitoring and Control: Many modern DVR systems allow for remote monitoring and control via mobile apps or web interfaces. Users can receive real-time alerts and take action (e.g., activate alarms or unlock doors) remotely.
   
   
   Customized Event Triggers: DVRs often offer programmable event triggers and outputs, allowing users to define specific conditions that lead to alarm activation. This customization caters to the unique security needs of different environments.


Evidence Preservation: When an alarm is triggered, the DVR can automatically start recording video footage and save it to a secure location. This ensures that critical evidence is preserved for investigative and legal purposes.

The alarm output ports on the back of the DVR are each labeled with NO C NC. The NO stands for normally opened, NC means normally closed, and C means common contact. When the alarm is in the non-triggered state, it is normally closed which means that the circuit is allowing current to flow from C to NC. When the alarm is triggered, the relay is enabled and switched from the normally closed (NC) to normally opened (NO) position.

The security application used in these instructions uses a 12v DC powered strobe light. The goal is to turn the strobe light on when an alarm is triggered. For this application, we will use a door contact connected to the alarm input of the DVR to trigger the output. 

Please note that the DC transformer used to power the strobe light / siren is only used to power the siren and has nothing to do with the power supply of the DVR. The concept is that the strobe light sits dormant / un-powered (relay in the NC position) until the alarm goes off. When the alarm goes off, the relay is enabled and allows power to flow to the strobe light (via switching the power of the circuit to the NO position), which turns it on.

WARNING: DVR alarm outputs / relays have a maximum power rating. The alarm outputs of DVRs have a maximum power rating of 2A 120VAC, 2A 24VDC. This rating should accommodate almost all standard burglar alarm equipment, but you should check the specification of each device to be sure. 

If you are using these setup instructions to guide you on integrating alarm devices on other types of surveillance DVRs is strongly recommended that you consult the manual of your DVR to understand the maximum power that your DVR alarm outputs can use. Using an alarm device that draws more power than the relays of your DVR are rated at will cause damage to the relay terminals and / or can ruin the entire DVR.

DVR Alarm Output Wiring

The siren in this example uses a 12v DC power supply. These typically have a single 3.5mm plug on the end of the cable. If your DC transformer has a single plug (instead of separate positive and negative wires), you can use a PT-4 pigtail power lead to convert the plug to separate positive and negative wires.

1. Connect the positive wire from the power supply to the NO terminal of the alarm-out port.
2. Connect the negative wire from the power supply to the negative cable of your output device (in this case a strobe light).
3.  Connect the positive wire from the strobe light to the C terminal of the alarm-out port.

DVR Alarm Output Configuration

In this example, we will use the input from a door sensor to trigger the alarm output (with strobe light connected to it). Please read these setup instructions for details about how the alarm input was configured for the door sensor.

Follows these instructions to configure the door sensor to trigger the alarm output.

1. Access the advanced setup of the DVR the clicking on the Home button, then select Setup > Advanced.

2. On the Advanced menu, click on the the Event tab, then click on the Sensor button.

3. On the sensor screen, you can can choose the action(s) that you want taken. To setup the strobe light on alarm output one to be triggered, click on the gear icon in the alarm section of the sensor action settings. This will open a sub-window that will let you choose to enable all alarm outputs or select the specific ones that you want triggered.

4. Click OK, then OK again to save the settings.

The alarm output of your DVR is now setup. When the door contact is opened, the strobe light will turn on.

It's important to configure and use DVR alarm output applications carefully to prevent false alarms and ensure that they are aligned with the security objectives of the organization or property. Proper integration, testing, and maintenance of the DVR system are essential to its effective operation in various security and surveillance scenarios.