Uninterruptible Power Supplies Alarm Monitoring and Control

Author: Robin Koffler

Uninterruptible power supplies (UPS) are sophisticated, microprocessor-controlled systems, capable of providing a range of alarm notifications and real-time monitoring information at local, network and remote site locations.

This is important because it offers peace of mind and negates the need for ‘warden-type’ manual inspection of power protection equipment. However, monitoring for alarm conditions is required. The beauty of today’s UPS equipment is that it can now be carried out at one location, either centrally in-house or off-site at a specialist UPS monitoring provider. Many leading power protection manufacturers, such as Riello UPS, provide this type of service. It often means an engineer can be on-site and have equipment repaired, checked and running before the client is even aware of a problem.

The decision not to outsource uninterruptible power supply monitoring must be reinforced by the provision of dedicated monitoring personnel in-house whose responsibility it is to monitor and respond to UPS alarms. Failure to act in a timely and appropriate manner will significantly reduce system resilience. Typical examples include failure to notice that a UPS is operating in bypass mode or that there is a failed battery in a battery string (note: a UPS battery string is only as strong as its weakest battery).

The advent of Html capability in the software arena has enabled modern UPS manufacturers to integrate sophisticated onsite and remote monitoring capability within their hardware. In fact, modern systems enable remote 24/7 monitoring (either by the client or at the manufacturer’s facility) of all critical UPS, generator, air-conditioning and fire suppression equipment. As well as alerting system managers to problems as they arise, integration of monitoring functions into existing infrastructures gives businesses valuable early warning of impending power and other equipment failures that actively increases profitable uptime.

Most UPS are available with software packages that monitor mains voltage, UPS load and battery charge as standard, as well as proprietary monitoring and control software, which allows remote interrogation of UPS logs and operating parameters to help diagnose alarms and faults. When instructed to do so, UPS software can remotely perform automated and controlled shutdown of valuable equipment - ensuring hardware protection while freeing personnel for other tasks during power continuity incidents.

Types of alarms include:

Audible Alarms: audible signals are generated from within the UPS or a connected remote status panel and may be coded, using varying lengths of sound, to indicate specific alarm conditions. Audible alarm signals will remain ‘on’ until the condition is rectified or the alarm is acknowledged and silenced.

Visual Alarms: light Emitting Diodes (LEDs) provide a basic form of visual alarm notification. They may be single or multi-coloured and indicate the status of the UPS by employing one of three modes: on, flashing or off.

Some UPS utilise Liquid Crystal Display (LCD) with push-button controls to provide a slightly higher level of visual alarm capability. In this case, the user can scroll through a menu of information (measurements and logs).

The most sophisticated level of visual display is a full front-panel graphic-type, which typically consists of multi-character back-lit lines that display information in alpha, numeric and symbolic formats, either as text, alarm codes, graphics or a combination thereof.

Remote communication can utilise one of several protocols to provide data-exchange between an application and its UPS: serial connection (including RS-232), Simple Network Management Protocol (SNMP), MODBUS/JBUS or Profibus.

A range of UPS monitoring packages are available from UPS suppliers - from simple installation software designed to run on laptops, PCs and PDAs to more sophisticated monitoring and control software that runs on an enterprise server (whether Microsoft Windows, UNIX, Mac, HP and many others) and provides a host of information from UPS operating conditions to WAP availability.

There are two common approaches to monitoring and control by uninterruptible power supply manufacturers: centralised and decentralised. Centralised is where a specified server is used to control the orderly shutdown of the mixed platform network. Decentralised is where each individual server or PC runs its own copy of the monitoring software and controls its own shutdown procedure. The centralised approach is the most straightforward and least expensive to install but it can introduce a single-point-of-failure into the system. Should the control server hang and fail to shutdown the rest of the routine will be disrupted leading to potential data loss and a system-wide crash. With the decentralised approach, if one server or PC fails to shut down, the problem is isolated, thus achieving a higher level of system resilience.

The human instinct upon hearing or seeing an alarm is often to ignore it but planning how to monitor uninterruptible power supplies and associated alarm signals, and conceptualising appropriate responses, is an important aspect of a power continuity plan. If you want to go into it in more detail, there is a whole chapter devoted to it in The Power Protection Guide.

by Robin Koffler - Aug 5th, 2008

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Robin Koffler is the General Manager for Riello UPS Ltd the UK subsidiary of Riello UPS (RPS S.p.A) a leading European manufacturer of Uninterruptible Power Supplies and a co-author with Jason Yates of The Power Protection Guide(ISBN 978-0-9554428-0-3)- available from Amazon.com

Source: http://www.articlesbase.com/information-technology-articles/uninterruptible-power-supplies-alarm-monitoring-and-control-510058.html

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