Komatsu 830E-AC Shop Manual page 420

Inverter Communications Processing
This software function performs the processing
necessary for the PSC system CPU card to
communicate with both inverter CPU cards. The
communication is through a high-speed serial link
that is operated in a polled fashion with the system
CPU card initiating communications to an inverter
CPU card.
Every message transmitted across the serial link
may contain two separate sections of information:
periodic data and acknowledged data. The periodic
data format is fixed and is used for transferring
control information from the system CPU card to the
inverter CPU card and
acknowledged data format is used to transfer all
background data. When
background data are to be transferred via the
acknowledged data format, the originating CPU card
will break the data down into smaller pieces and
transmit each piece individually. All acknowledged
data flows are initiated from the system CPU card
with the inverter CPU card providing a response.
The system CPU card has one high-speed channel
available for communications to the inverter CPU
cards. This channel transfers periodic data across
the serial link every 5 ms. This means that the
periodic data to each inverter CPU card is updated
every 10 ms. Each inverter responds to the data
when the ID code in the periodic data matches the ID
code of the specific inverter CPU card. The ID code
is hard-wired in the card's backplane wiring.
OUTPUT PROCESSING
This software function processes all external outputs
from the PSC. Refer to the G.E. publication System
Description for a listing of the PSC outputs.
E2-36
vise versa. The
large amounts of
Electrical Propulsion System Components
ABNORMAL CONDITIONS/OVERRIDING
FUNCTIONS
Software functions given up to this point have
assumed that the truck is operating under typical
circumstances. The following information defines
system operation under abnormal or exceptional
circumstances. In the event of conflict between these
functions and those given for normal operation, the
following functions will take precedence.
Fast Start
A fast start software function is provided to address
the case where the PSC is reset unexpectedly
(power supply glitch, for example) while the system is
running. Its purpose will be to regain control of the
truck as quickly as possible.
Engine Shutdown/Engine Not Running
The engine must be running to enable the gate
drives and to maintain power on the DC link.
Typically, the PSC will be given advanced warning
that the engine is about to be shut off. However, if the
engine stalls or stops because of a mechanical
malfunction, the system will most likely have no
advance warning.
The system reaction to an engine not running
condition will be the same as an event carrying a "no
power" restriction except that no event will be
recorded and no external reset to clear the condition
will be required. The "no power" restriction will be
automatically lifted as soon as the engine starts
running.
If the system is given warning of an impending
engine shutdown, the existing torque commands will
be command to zero over a "long" ramp time (2 to 10
seconds). If no warning is given and the engine stops
running, the existing torque commands will be
command to zero over a "short" ramp time (0.1 to 0.5
second).
10/06 E02020