How to select and install the right network server UPS installation including battery sizing, UPS communications interfaces, accessories and battery runtimes.
UPS monitoring software is supplied with most uninterruptible power supplies as a website download link or on a DVD/CD-ROM package. The UPS will have a USB/RS-232 interface and/or an option for a plug-in communications card. For an IP network, the most commonly used card is a UPS SNMP card. UPS monitoring and control software can display realtime graphs and readings, access historical logs, display alarm messages and broadcast them and be configured to automatically shutdown the network file server at a preset time when the uninterruptible power supply runs on battery i.e. during a mains power failure, to preserve data and prevent damage to the server.
It is important to position the UPS close to the network server. The standard power cord length may be 1, 2 or 3metres. Space should be left around the uninterruptible power supply for airflow. Rackmounted systems sit within a server rack and the middle to bottom of the rack is the most suitable place for the rackmount UPS system. If the network server is floor standing, the most suitable UPS is a floor standing or tower version that can sit beside the server. If small line interactive or standby UPS are used these can sometimes be placed on the top of the server cabinet or an adjacent shelf provided their is adequate air flow. Care should be taken to to place power cords and UPS interface cables so that they cannot be accidentally disconnected or present a trip-hazard within the room.
A and B power supply resilience can be provided by adding an automatic transfer switch (ATS) to the critical power circuit. An ATS is sometimes referred to as an STS and operates by automatically selecting between two power sources whether these are the outputs from two UPS systems or two mains power supplies or a combination of these two. When one power source fails, the other is automatically brought into circuit to power the server loads. Manual selection is also possible. An ATS is a relay-based device. An STS uses static electronics transfer switch technology.