To attach an external controller to the distribution matrix:
Connect a serial cable between the external controller and one
of the serial ports on an enclosure (preferably serial port 1 of
the master enclosure). Transmit, receive, and ground must be
run from the external controller to the distribution matrix.
Since no handshaking is provided by the distribution matrix,
make the serial cable connector pinouts as seen in figures
4.13 - 4.17. If multiple enclosures are linked, connect the ex-
ternal controller to the master enclosure using serial port 1.
Daisy-chain the rest of the enclosures as shown in figure 1.2,
in section 1.3, “Linking Enclosures.”
Before attaching an external controller, the distribution ma-
trix’s configuration word needs to be updated. Detailed
information about the configuration word is in section 2.6,
“Changing the Configuration Word.”
If you are using SBCs with the distribution matrix, you must
allow it to poll all the SBCs. The CPU polls the SBCs for any
change requests. If the CPU finds a switch, it is made imme-
diately.
After the serial connections are made and the distribution
matrix is powered up, the external controller screen displays
the version number, the slots of the enclosure that contain I/O
boards, and specific information about those boards. If the
message does not appear on the screen, the serial port the ex-
ternal controller is attached to may be set to poll SBCs.
Change to Program mode and check the setting of the respec-
tive serial port. See figure 2.3, in section 2.6.10, “Setting the
Configuration Word,” for further explanation. Also verify
communications protocol by checking the jumper on the CPU
board.
Your distribution matrix should now be ready to be operated
via the serial port.
4.5
Using a Dumb Terminal
A dumb terminal is a non-programmable input device that
sends ASCII characters to the master enclosure. An example
of a dumb terminal is a keyboard attached to the serial port of
a 1YDM master enclosure. A dumb terminal could also be a
keyboard and monitor, where the keyboard sends the ASCII
character and the monitor displays the echo.
When you are using a dumb terminal, the capitalized ASCII
character must be sent to the master enclosure. The terminal
must transmit at 9600 BAUD with 8 data bits, 1 stop bit, and
no parity.
4-13
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