CertiGuide to A+ (A+ 4 Real)  9  Chapter 11: Power Supplies, Surge Protection and Uninterruptible Power Supplies       9  Uninterruptible Power Supplies (UPSes)

What Size UPS? 1 Further Information Links

A UPS system alone can provide protection from brief power problems. During an extended power outage an unattended system will eventually shut down due to the battery running down. To prevent data from becoming corrupted during an improper shutdown, the UPS must inform the computer of its impending shutdown. The computer is then able to execute an orderly shutdown and close any open files. This is known as "UPS Monitoring¹⁴⁵". The UPS communicates with the computer system by means of a computer interface port. Some computer operating systems have built-in UPS monitoring. Others need monitoring software that is generally supplied by the UPS manufacturer with units that have this interface capability.

Low-end UPS units will interface with the host computer by way of an RS-232 port or through a USB port. Monitoring software will run as a background process to offer user notification of impending shutdown, power event logging, auto-restart upon power return and UPS battery condition.

Higher-end UPS units can communicate by means of a network connection and TCP/IP to provide UPS¹⁴⁶ monitoring by using the Simple Network Management Protocol (SNMP) connection. SNMP¹⁴⁷ connectivity involves the use of network monitoring and agents, to assess UPS conditions and provide for remote shutdown in the event of power failure.

Remote Management and Network Monitoring Capabilities save administration costs and provide the ability to:

• Set alarms for problem conditions
  
  
• Remote alarm notification
  
  
• Local and remote system shutdown
  
  
• Remote booting and load control
  
  
• Instantaneous power status - input/output voltage and power
  
  
• Record power and event histories
  
  
• Power System Monitoring & Control

What Size UPS? 1 Further Information Links