Table of Contents
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Understanding
the Computer Module
The Function Cards
FE-LINK
The FE-LINK is a high-speed (500 kilobaud) serial link for passing digital data, status and
control between the recorder modules and the Rack Interface. When the system is switched on
the interface card polls the rack to identify the modules that are plugged into the rack.
Pol.ling
The modules place their data onto the FE-LINK in response to a poll from the Rack Interface.
The Parameter IDS are placed into a Scan lllzb2-e when the system is switched on. This scan
table is used to decide when to poll each parameter. A scan table entry consists of a complete
description of the parameter to be polled, including ID, rack address, number of bytes to
receive and transmit, etc.
Rack Interface Connection
The Rack Interface card must be placed in slot 18 on the front of the computer module. This is
so the 20-pin connector, on the back of the integral rack, aligns with the connector on the edge
of the interface card when the rack is mounted on the front of the computer module.
DGDC Power
The 60V supply from the DC/DC converter is placed on all the rack connectors to supply power
to the integral rack via the FE-LINK cables.
Data Transfer
The method for data transfer used
by
the Rack Interface can be called RAMMuEtipkming. Two
RAMS are used alternately by the on-board 8051 microprocessor and the 68000 on the Utility
CPU. Every 32ms the RAMS are switched, using the 32ms frame-interrupt from the Utility CPU,
so the RAMS can be accessed by the other processor. This allows the faster 68000 processor to
exchange data with the RAM and then run-on before the RAMS are switched.
The on-board 8051 microprocessor then converts the data into serial data for passing to the
racks over the FE-LINK with no further intervention by the Utility CPU.
Received serial data from the recorder modules, via the FE-LINK, is converted to parallel data
and placed into the RAM by the on-board 8051. The RAMS are then switched allowing the
Utility CPU to exchange data again.
Summary
n
Translates serial data from the FE-LINK to parallel data for transmission to the Utility CPU
over the 8-bit local bus
n
Translates parallel data from the 8-bit local bus to serial data for transmission over the
FE-LINK.
n
RAM multiplexing eliminating intervention of the Utility CPU during data transfer.
m Routes the power from the DC/DC converter to the integral and satellite racks.
n
RS422 Configuration Port for external computer via FE connector.
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Table of Contents
Troubleshooting
