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UNINTERRUPTIBLE POWER SUPPLIES
It ’ s normal practice to monitor critical alarms continuously and in real time , while the operational status can be requested as needed by a system administrator or supervisor . As there ’ s no European standard for UPS RS-232 protocol , each manufacturer offers its own implementation . Additionally , most UPS suppliers offer proprietary software to extract the most useful information from the serial data , although the features offered vary between suppliers .
Such software runs under most operating systems and , as
Fig . 1 below shows , typically offers facilities including :
• A graphical display of UPS status , voltage , current , load , battery voltage , frequency and other parameters
• Configurable responses to certain alarms , such as broadcasts to users
• Scheduled diagnostic checks and data logging
Fig . 1 : Typical UPS monitoring screen
An SNMP adaptor is a hardware component that connects the UPS onto the network . Software provided with SNMP adaptors should be compatible with all popular operating systems , and offer features including :
• Remote control and rebooting of UPS protected devices over the network or Internet
• Protection of information and systems through automatic and graceful shutdown of multiple UPS protected devices during an extended power failure
• Generation of real time email , mobile phone or SMS alarm notifications
• SSL and SSH data encryption and authentication capability
• Web pages served automatically in the selected local language
• Activity and alarm logging
An intelligent SNMP enabled UPS may be able to control its connected devices , for example turning them on or off . This would allow a system manager to isolate sections of the load for security purposes , shut down devices to reduce energy consumption , and manage redundant portions of the system .
Because intelligent UPS condition power , system disruption due to power disturbances can be dramatically reduced . The UPS can log power disturbances , track battery usage , issue alerts of low battery problems and record power level history . Through SNMP , this information is available to managers and supervisors for immediate analysis and to detect potential problems before they cause disruption .
SNMP allows operators to manage the UPS load more efficiently as well as controlling the UPS itself , by linking large numbers of UPS into a network and feeding status data to the central network console . If required , UPS communications can be integrated with a third-party remote management resource . These packages can constantly scan its client UPS systems , automatically detecting any error or alarm messages . n
Other serial interfaces in current use include RS-485 and RS- 422 for longer-distance communications . RS-422 is generally favoured as it ’ s full-duplex and minimises problems . Modern UPS also incorporate USB interfaces to enable real time monitoring .
Networking and SNMP As systems become more complex , distributed over a wide area , or run more critical applications , a more sophisticated network-based strategy becomes essential . A widely adopted and successful solution is the System Network Management Protocol ( SNMP ), which is part of the Transmission Control Protocol / Internet Protocol ( TCP / IP ) suite . It allows a network manager to supervise and control many devices across an enterprise network from a central location . Data can be exchanged between these devices in a mutually compatible format . This is true even for wide-area networks comprising several remote sites , some possibly unmanned , and distributed over an extensive geographical area .
A UPS with SNMP capability becomes an intelligent device that can for example :
• Log events
• Continuously monitor power quality
• Report on battery status , load and temperature
• Perform self-diagnostics
Fig . 2 : Automatic call-out facility with PowerREPORTER
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