D20/D200 Technical Overview
GE Grid Solutions
36
PRPI-019-3.00-10
GE Information
The IRIG B format supports the time of day (hours, minutes, seconds) and the day of the year.
The day of the year is the elapsed day starting from January 1
st
, and is reported as a number from
1 to 365 (366 for leap years). Year information is not provided by the IRIG B signal. Accuracy to
milliseconds is obtained by tagging the leading edge of the pulse train to the time defined by the
pulse train.
2.3 Ethernet/Memory Expansion (EME) Kit
The D20EME is a VME-based module that combines Ethernet support and global memory
expansion. If you install multiple D20ME or D20ME II main processors in the D20 or D200
VME chassis, you will need to install a D20EME Ethernet/Memory Expansion module to
provide shared memory.
Figure 22 D20EME (Ethernet/Memory Expansion)
The D20EME allows VME-based D20 and D200 systems to be connected directly to any
10 Mbps Ethernet-based network. Available configurations of the D20EME module include:
•
Ethernet only
•
Memory only
•
Ethernet and Memory
Memory configurations come equipped with 8 MB of battery-backed static RAM. This additional
memory increases the amount of historical data, and the size of the database, that can be
maintained by the D20/D200. Memory capacity can be upgraded to 16 MB, through the
installation of an additional memory module.
Ethernet configurations are equipped with two independent 10 Mbps Ethernet channels. A Media
Interface Card provides the physical Ethernet interface. Several versions of the MIC are
available, depending on the Ethernet format.
Table 5 D20/D200 Ethernet Media Types
10BASE-T
Provides two RJ-45 connectors for connecting to CAT5, or greater, UTP cabling
10BASE2
Provides two BNC connectors for connecting to thin coax cabling
10BASE-FL
Provides two ST-style connectors for directly connecting to a single or multi-mode glass or
plastic fiber optic cable
