Specifications

18 Application Module
X
Service 3/96
Honeywell Inc.
Hardware Description of LCN Node Processors
3.2 HMPU Processor and Associated Boards
LLCN board
functionality
The LLCN board provides the LCN interface functionality used by the
HMPU node processor. The actual connection to the LCN cables is through
the CLCN A/B I/O (or LCN I/O) board which is inserted in the I/O card
chassis immediately behind the LLCN board (same board slot).
The LCN node address is pinned on the
CLCN A/B I/O (or LCN I/O) board and is covered later in this section.
LLCN board
indicators
The LLCN board indicators are visible from the free edge of the board
when it is installed in a chassis. They provide visual indications regarding
the existing conditions on the board.
LLCN indicator
description
The following table gives a description of the indicators on the LLCN
board. Reference the preceding diagram.
Table 3-3 LLCN Indicators
LED Description Suspected cause if abnormal
Self-Test/Error On to indicate a board self-test
error. Normally off.
LLCN
Pass module test On after board passes self-test.
Normally on.
LLCN
Bus Trans Error On to indicate a detected
backplane bus parity error.
Normally off.
LLCN, other board(s) in chassis,
or backplane
Tx Transmission on LCN from this
board is taking place. Normally
on or blinking rapidly (on a loaded
node).
LLCN, HMPU, or LCN cable
problems.
40024
LLCN
TXBus
Trans Error
Pass
Mod Test
Self
Test/Error