Network Problems with Master/Slave or Server/Slave Con- figurations

When working with a master/slave or server/slave configurations (one UPS powering more than one computer), the master/server and slave commu- nicate via the network. In many configurations, apcupsd is started before the network is initialized. In this case, it is possible that the master will be unable to contact the slave. On apcupsd versions prior to 3.8.0, this could cause apcupsd to error off. The solution to this problem is to either force apcupsd to be started after the network and the DNS (fiddle the sym- bolic links in /etc/rc.d), or put the names of the slave machines in your /etc/hosts file, or even more preferable, use IP addresses rather than ma- chine names. On some configurations, you may need to use fully qualified names (host.domain.xxx) rather than simple host names.

Error Messages from a Master Configuration:

In a master/slave configuration, you can get the following error messages from a master. The error message is followed by a possible explanation:

resolve slave name XXX

To contact the slave, the slave name given in the configuration file must be resolved to an IP address. In this case, apcupsd could not get the IP address. Either the slave name is incorrect, your DNS may not be working, or you have started apcupsd during the boot process before the network is operational.

slave shutdown from SSS

This message should not be printed as it is not yet used.

write to slave SSS

This message occurs when the master attempts to send a message to the slave SSS and gets an error. It indicates that either the slave machine is not responding (apcupsd died, the system crashed, ...) or that the network is down.

read magic from slave SSS

This message indicates that the master attempted to read the code key from the slave SSS and it did not match the value expected. A common cause of this problem is that the master and slave versions of apcupsd are not the

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UPS control system specifications

APC UPS (Uninterruptible Power Supply) control systems are vital components for ensuring uninterrupted power supply and protecting critical equipment from power interruptions, surges, or fluctuations. Designed by Schneider Electric, APC UPS systems are renowned for their high quality and reliability. They utilize advanced technologies and features to suit diverse applications, from home offices to large industrial settings.

One of the main features of APC UPS systems is the ability to provide backup power during outages. This is achieved through a battery system that activates immediately when the mains power fails. This seamless transition minimizes downtime and ensures that electronic devices continue to operate, protecting data integrity and equipment lifespan.

Another significant characteristic of APC UPS systems is their intelligent management capabilities. Most models come with PowerChute software, which provides users with real-time monitoring of power conditions and the status of the UPS. This software allows for graceful shutdowns of connected devices during extended outages, thereby preventing data loss and damage to devices.

APC UPS systems also incorporate advanced technologies such as Automatic Voltage Regulation (AVR). AVR technology ensures that the output voltage remains stable by correcting minor fluctuations without switching to battery mode. This not only prolongs the battery life but also provides a consistent power supply to the connected equipment.

Thermal management is another critical aspect of APC UPS control systems. The design often includes efficient cooling systems that prevent overheating, ensuring optimal performance and longevity of the unit. Some models feature EcoMode, which reduces energy consumption and lowers operational costs by working at high efficiency only when battery backup is not required.

APC UPS systems are designed with scalability in mind. Users can easily add more batteries or connect additional UPS units to accommodate growing power needs. Features such as hot-swappable batteries and modular design facilitate easy upgrades and servicing without interrupting power supply.

In terms of connectivity, APC UPS products often feature multiple options including USB, RS-232, and network management capabilities. This enables users to connect remote management tools and integrate the UPS with existing IT infrastructure.

In summary, APC UPS control systems deliver reliability, efficiency, and advanced technology features that cater to a wide array of power protection needs, making them a trusted choice for individuals and businesses alike.
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