Event Logging And Storage; Event History Buffer; Data Packs - Komatsu 930E-2 Shop Manual

Event Logging And Storage

This software function is responsible for the recording
of event information. There are two basic levels of
event storage: event history buffer and data packs.
The event history buffer provides a minimum set of
information for a large number of events, while data
packs provide extensive information for a limited num-
ber of events.
The following requirements apply to both data packs
and the event history buffer:
1. Fault information is maintained until overwritten,
it is not cleared out following a reset. This allows
the user to examine data associated with events
that have been reset, as long as there have not
been so many new events as to necessitate reuse
of the storage space.
2. If a given event is active (logged and not reset),
logging of duplicate events (duplicate is defined
as having the same event and sub-id numbers)
will not be allowed. If the event is reset and
subsequently reoccurs, it may be logged again.
Likewise, if an event reoccurs with a different
sub-id from the original occurrence, the event
may be logged again.

Event History Buffer

Event history buffer is defined as a collection of event
history records.
A buffer contains 300 entries filled with event numbers
occurring in chronological order. Also included in this
buffer will be all the input and output values, time the
event occurred, reset time, state information, etc., for
each event. This buffer is filled continuously and over-
written (if necessary).
Limits (accept-limit) are placed on the amount of space
which a given event code may consume. This prevents
a frequently occurring event from using the memory
space at the expense of a less frequent event. This
data may be cleared (after downloading for trou-
bleshooting) at each maintenance interval.
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Data Packs

A data pack is defined as an extended collection of
information relevant to a given event.
NOTE: The concepts of lockout, soft reset, and accept
limit do not apply to data packs.
Thirty (30) data packs are stored with each containing
100 frames of real time snapshot data. Snapshot data
is defined as a collection of key data parameter values
for a single point in time). The purpose of each data
pack is to show a little "movie" of what happened
before and after a fault.
The time interval between snapshots is default to 50
ms, but each data pack may be programmed via the
DID (or PTU) from 10 ms to 1 sec. (In multiples of 10
ms). The "TIME 0:00 frame #" at which the fault is
logged is default to frame #60, but each data pack is
programmable from 1 to 100.
In the above default cases, data is stored for 3 seconds
(2.95 second is actual) before the fault and 2 seconds
after the fault.
A data pack status structure is assigned to each data
pack plus any programmable settings. This status
structure is used by the TCI (or PTU) to check for
available data (event number, id, and status, should
be set to zero if data pack is not frozen), as well as for
control of the data packs.
If a data pack is unfrozen (not holding any particular
fault data), it is continually updated each 100 frames,
organized in a circular queue, with new real time
snapshot data. When a fault occurs, the frame number
at which the event occurred is used as a reference to
mark the end of the data pack, and data is collected
until the data pack is full. Only when the data pack is
full will the event number, id and status be updated in
the status structure.
All logic control variables are saved in battery backed
RAM, in case a fault occurs and battery power is cycled
before the data pack is filled with data (the software
allows for proper recovery and then continues to fill the
data pack). Maintenance personnel, by way of the DID
(or PTU), can assign the data pack to hold only certain
event numbers (for the case where it is desired to
collect data on a particular fault).
However, in the default case, faults will be stored as
they come until all data packs are frozen (holding fault
data). When all data packs are frozen, the data pack
with the fault that was RESET first (either automatically
or by the DID/PTU), if any, will be unfrozen and will
start storing new data in case a new fault occurs.
Electrical Propulsion System Components E02014 3/01