Environmental Monitoring Unit
Chapter Three
EMU
Environmental Monitoring Unit Configurations
Introduction
The Environmental Monitoring Unit ( EMU ) is a multifunction plug-in daughter card that allows a user to monitor the operational status of a Voyager 3000 system. There is one EMU per storage shelf. The module provides visual and audible feedback of events to the user. In addition the EMU provides addressable memory locations which may be read or written to. This allows more comprehensive monitoring and reporting to intelligent agents such as Eurologic’s Vision software. The EMU specification is based on the SAFTE ( SCSI Accessed Fault Tolerant Enclosures ) specification, and contains many of the features detailed there.
EMU Features
∙Monitors presence and status of Fans and Power Supply Units ( PSU ) .
∙Monitors presence of SCSI devices.
∙Monitor UPS status and presence.
∙Indicates error conditions visually and audibly.
∙Adjustable over-temperature warning.
∙Stores insertion counts for all removable devices - PSU, Fan or SCSI Device
∙Communication via serial RS232 port or via I2C bus.
∙Fully compatible with Eurologic’s Vision software.
The EMU is a flexible unit which may be configured in a variety of ways. It connects to a host system via an RS-232 link. Up to eight EMUs may be cascaded together in a Master/Slave configuration. Each EMU is set up to have a distinct ID. A device having an ID of 0 will be a Master, all other devices are designated as Slaves. Multiple EMUs are daisy chained together via an I2C bus.
The EMU stores data in a non-volatile EEPROM memory so it is possible to track changes in the system even if power has been removed. On power up the EMU compares the physical system configuration to that stored in memory and notes any changes. These changes will be reported to the Host. It is the responsibility of the Host to process this information.
