Computer Description; Software - Komatsu 830E Shop Manual

COMPUTER DESCRIPTION

A total understanding of the following concepts is not
essential to properly maintaining and troubleshooting
the Komatsu truck control system. This information is
presented as additional background information con-
cerning operation of the FL275 panel computer and
software programs required for operation. The techni-
cian should however, become familiar with basic oper-
ation of portable, MSDOS operating system computers
(PTU) and must have the ability to use the menu oper-
ated software described later in this publication. These
skills are necessary for programming the FL275 panel
computer, troubleshooting, and obtaining statistical
data.
Microprocessor
The microprocessor, located on the FB101 card (or
FB144 card on later model trucks), contains the logical
elements necessary to perform calculations and to
carry out stored instructions. It is used as the central
processing unit (CPU) of a computer. Computer opera-
tion is managed by a software program, which resides
in the computer's memory. The software program also
contains instructions to test and fault isolate the sys-
tem.
A program is a sequence of specific instructions in an
order that, when the microprocessor executes them,
proper results occur. A program is generally stored in a
read-only-memory (ROM). To execute the program,
the microprocessor reads an instruction from ROM,
interprets the instruction, performs whatever task that
is dictated by the instruction, and then starts the pro-
cess over again by reading a new instruction from
ROM.
The microprocessor utilizes address, control, and data
buses to accomplish the above process. A bus is a
group of wires or circuits that collectively serve a simi-
lar function. For example, the address bus identifies
the location that the microprocessor is reading from or
writing to. The data bus provides a path for the flow of
data from one point to another. The control bus is
somewhat different from the other two buses in that
each wire normally serves a separate and generally
unrelated function used to control the actions of the
system.
While executing the program, reading and writing of
data is often necessary. This data is stored in a ran-
dom-access-memory (RAM). A RAM is a temporary
storage device, that is, if power to the RAM is lost, the
data is cleared. The RAM stores all types of data, such
as, input/status from external devices, fault information,
specific program addresses, etc.
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The final result is to provide instructions to external
devices that tell them when and/or how to operate.
Throughout the execution of the program, the micro-
processor acts like a traffic officer; taking in instruc-
tions, interpreting them, and acting accordingly in order
to process instructions to the output.
Download Capability
The computer can be reprogrammed by "downloading"
new software into its memory. Downloading refers to
transferring software program instructions from the
PTU to the FL275 panel FB101/144 card through the
serial port connector cable. This capability allows the
system software to be changed if any new hardware or
software option is to be installed or if an updated ver-
sion of the existing software is to be implemented.

SOFTWARE

"Software" refers to computer programs written using
coded instructions that can be understood by the CPU.
The following is a brief description of how the software
establishes and regulates propulsion and retarding.
Base Monitor Program
The Base Monitor Program performs functions for the
system, including power-up tests on the CPU card.
This software is programmed on four Eprom chips at
the factory and installed on the FB101/144 card.
Runtime Monitor Program - OBJRunning Code
The Runtime Monitor Program is used to control com-
mon truck functions. It is downloaded to Flash (Electri-
cally Erasable Read Only Memory) chips on the CPU
card from OBJ files stored on the PTU hard drive. This
is done initially during factory check-out and can be
redone in the field using the PTU.
After being downloaded to Flash, it is then copied to
RAM (Random Access Memory) chips on the CPU
card at system power-up.
This software:
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Electrical Propulsion Components
Controls contactors, relays, lights, solenoid, fir-
ing pulses, etc.
Monitors truck running parameters and stores
event/fault data for later examination.
Communicates with the PTU to display operat-
ing parameters and event/fault data.
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