A video surveillance system that must ensure the safety of an environment cannot ignore the presence of an uninterruptible power supply (UPS) that provides continuity and energy quality. This apparently intuitive concept, however, deserves further study.
A thief, before violating a building, always tries to cut off the power supply. He is well aware that safety regulations require many electric locks to open automatically in the event of a power failure, thus facilitating his “work”. Not only that, with reference to security systems, burglary professionals know very well that:
• many installers neglect the installation of an emergency power supply in the construction of video surveillance systems. In this way, by opening the main power supply, they put the system out of use;
• very often due to lack of maintenance of the batteries supplied with the UPS, the latter are discharged or damaged. By eliminating the main power supply, the safety systems also go out of service.
This explains why the CONTINUITY OF ENERGY IS THE FIRST AND THE GREATEST FORM OF GUARANTEE for the safety of environments.
It is always good to remember that power surges are a very frequent phenomenon. Unfortunately, video surveillance systems are made up of devices that are particularly subject to failures caused precisely by these anomalous oscillations.
- The hard disks on which the recordings are made need an absolutely stable voltage. The read / write operations can be irremediably altered in the event of an irregular power supply, which can also cause the electronic components to break;
- The cameras have delicate electronic controllers whose circuitry could be damaged if reached by abnormal oscillations.
- The LEDs, fundamental in modern video surveillance systems, are very sensitive to voltage fluctuations. In systems whose project does not involve the use of the UPS, it often happens that after a few months the cameras have burnt out the LEDs of the illuminator (which forces the cameras to be changed).
- If you want your video surveillance system to last a long time and perform its function reliably, it is essential that you protect it with a suitable UPS. In short, a UPS EXTENDS THE LIFE… OF YOUR SYSTEM.
How to choose UPS for video surveillance?
Once we understand the importance of an uninterruptible power supply capable of ensuring the operation of the system for a certain time even in the event of a blackout and that protects the devices from irregularities in the power supply, let’s dedicate ourselves to understanding the criteria to be followed for choice of the most suitable UPS.
Small and medium-sized video surveillance systems have a rather low power consumption. The protection they require against network disruptions are fairly straightforward to provide.
This means that they can be adequately protected by Line Interactive (VI) UPS, i.e. TYPE equipped with a technology that guarantees intervention in the event of a blackout or voltage fluctuations after a few milliseconds (2-4 ms.), A latency time perfectly compatible with the continuity of operation of the system. In addition, these UPS are equipped with an automatic adjustment device (AVR) capable of handling small voltage fluctuations even before the direct intervention of the batteries.
The “Line Interactive” systems are therefore ideal for the vast majority of video surveillance systems, where they are appreciated for their low cost, low management and installation costs.
A further distinction of the UPS Line Interactive is the type of output waveform which can be:
– Pseudo Sinusoidal (typical of entry-level devices and suitable for IT loads)
– Sinusoidal (typical of the most advanced models and suitable for sensitive equipment).
In the case of more sophisticated systems and with a strong presence of IT components, it becomes advisable to adopt UPS with double conversion ON LINE technology (VFI), where in normal operation the loads are powered by the rectifier / inverter combination, ensuring perfect quality of power supply, independent from the network, both in voltage and in frequency. In the event of a blackout, the switching time for battery operation is instantaneous (0 ms).
The first thing to evaluate is the power of the UPS according to the system. In particular, the most common video surveillance systems consist of a 4/8/16 channel DVR (analogue or digital) with relative cameras; they are systems that operate normally at 12 V and have a relatively low absorption (from about 5 to 15A). This means that even with UPS of low rated power, it is possible to give the system considerable autonomy, even over 30 minutes.
– A 650 VA UPS is in fact sufficient to power a 4-channel system for up to half an hour
– A 1200 VA UPS can do the same thing with a 16 IP camera system.
Another aspect to take into consideration is that cameras are devices designed to remain always under voltage, while what starts and stops is video recording. Video management devices such as monitors and DVRs must also be protected with UPS.
In this regard, it is good to remember that some cameras powered by battery with Pseudo-sinusoidal wave UPS, may incur flickering and disturbances in data recording.
It is therefore recommended to adopt models with a sine wave shape. A very professional solution consists in creating a distribution network to power all the cameras with one or more centralized power supplies. These devices connect to the 220 V network and provide a certain number of outputs each capable of powering a camera. This solution avoids the arrangement of the power supply near the camera and allows the centralized connection of the whole system to a UPS.