Low Power Video Surveillance System

Monday, November 15, 2010 @ 05:11 PM gHale


Originally developed for a major oil and gas company to monitor remote wells in North America, the Longwatch XLP Low Power Video Surveillance System is powered by solar cells and batteries.
The system hibernates in a low-power standby mode until an external sensor, such as a motion detector or intrusion alarm, or a command from the central control room sends it a signal to wake up. The system immediately records a short “video alarm clip,” transmits it to a remote operator at a central HMI/SCADA system, and continues to record video on its disk until commanded to return to hibernation.
Typical well sites use low-bandwidth line-of-sight VHF radios with industrial protocols such as Modbus. The XLP system can transmit its video clip to the control room using an RF data link, where the user can view it using the Longwatch Viewer or integrated into the HMI/SCADA system. The Longwatch software makes minimal use of the available bandwidth, so it does not interfere with control and instrumentation data. The XLP can also use Ethernet, wireless, cellphone or satellite communications when power consumption or bandwidth is not a concern.
Once the operator sees the alarm video clip and message on the HMI screen, he or she can then command the Longwatch system to transmit live video, and remotely pan, tilt and zoom the site cameras to further investigate process or intrusion alarms. This allows the operator to see exactly what is happening at the remote location and determine the next course of action, such as dispatching a maintenance crew to repair a leak or summoning the local police to deal with intruders. Video enables the operator to quickly decide the best action to take to provide safety and reduce downtime or environmental impact.
The low-power video surveillance system can operate on a minimal power budget. At remote well sites, the instrumentation, controls, RF communications and the video system are get their power from a solar system and batteries. Each component has to conform to a rigid power budget. For that reason, the Longwatch XLP system goes into “hibernation mode” to conserve power.
In hibernation mode, the Longwatch XLP system’s processor, solid-state disk and most peripherals are inactive, so it consumes very little power while waiting for a wakeup signal. The wakeup signal can be an intrusion alarm, process alarm, or a request from a remote system, such as the central HMI/SCADA system. The Longwatch system can return to hibernation mode either automatically or on command after a period of activity.
For such an application, where the video surveillance system must respond instantly, the user should not use digital cameras. Not designed for hibernation, digital cameras take a minute or longer to “boot up,” and can miss valuable video coverage. For that reason, Longwatch recommends using traditional analog video cameras, which turn on almost instantly. With analog video cameras, the low power Longwatch XLP video surveillance system can begin capturing live video within 6-7 seconds of an intrusion or process alarm – up to ten times faster than a digital camera.
The Longwatch XLP Video Surveillance System, with the help of Advantech’s Design To Order Service (DTOS), can help solve the problem of how to monitor sensors and wake up the video system.
The XLP uses an Advantech UNO 2173 Atom-based computer. The UNO 2173 has a 1.6GHz Atom processor, 1GB of memory, Windows XP/E operating system, and battery-backed SRAM. When operating, the fanless UNO requires only 12W of power.
Based on Longwatch’s requirements, Advantech’s DTOS group created a custom digital I/O board for this application so it could monitor digital inputs even in hibernation mode. It takes inputs from gate sensors, motion detectors and intrusion alarms—or digital inputs from the site’s RTU, such as leak detectors, pressure switches, etc. When it detects one of the digital inputs, it wakes up the XLP video system. When the XLP’s computer and UNO I/O board are in hibernation mode, the entire system consumes less than 2.5W.



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