Serial Data Communications; Output Processing; Event Reset; Psc - Ptu Communications Processing - Komatsu 930E-2 Shop Manual

Event Reset

There are two basic types of event resets: soft and
hard. The difference between the soft and hard reset
is a soft reset only affects events that have not been
locked out and a hard reset affects events regardless
of lockout status.
• Events will be reset:
On powerup - a soft reset will be issued against all
events at powerup.
By DID commands - the TCI can issue both hard
and soft resets.
By PTU commands - the PTU can issue both hard
and soft resets.

SERIAL DATA COMMUNICATIONS

The PSC System CPU Card uses serial data busses
to communicate with the TCI, the PTU, and the two
Inverter CPU Cards.
PSC - TCI Communications processing
This software function performs the processing neces-
sary for the PSC (System CPU Card) to communicate
with the TCI through an RS-422 serial link. The com-
munication is comprised of periodic data and non-pe-
riodic data.
Periodic data is a predefined set of data which is used
for transferring real time control information from the
PSC to the TCI and from the TCI to the PSC at a fixed
rate.
The non-periodic messages are used to transfer all
background data. Background data consists of DID
Commands, Remote Monitor Data, and Download
Code.
Packets containing periodic data will be asynchro-
nously (not initiated) transmitted from the PSC to the
TCI and from the TCI to the PSC every 200 ms. The
TCI initiates the transfer of non-periodic data.
The TCI and the PSC are interfaced using the General
Electric Asynchronous Communications Protocol
(ACP). ACP provides two general types of messages,
acknowledged and unacknowledged. The unacknow-
ledged messages are used to transmit the periodic
data.
The acknowledged messages are used to transmit the
background data.
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PSC - PTU Communications Processing

This software function performs the processing neces-
sary for the PSC (System CPU Card) to communicate
through an RS-232 serial link to the Portable Test Unit
(PTU).
Inverter Communications Processing
This software function performs the processing neces-
sary for the System CPU Card to communicate with
both Inverter CPU Cards. The communications 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 for-
mat is fixed and is used for transferring control infor-
mation from the System CPU Card to the Inverter CPU
Card and vise-versa. The acknowledged data format
is used to transfer all background data. When large
amounts of background data are to be transferred via
the acknowledged data format, the originating CPU will
break the data down into smaller pieces and transmit
each piece individually. All acknowledged data flows
are initiated from the System CPU with the Inverter
CPU 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 the periodic data
to each Inverter CPU 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 hardwired 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.
Electrical Propulsion System Components E2-39