Relay Control
The
Relay Control controls the state of the output relay.
Input Conditioning and processing
This process is the largest and most complicated of those listed.
The actual correlation and
computation of input data and
the
decisions on whether a given measurement is within
the
set[X>int range
is accomplished her� This capability
for
high-speed processing
and
ability
to
dynamically change the
weight of input conditions is one justification for the incorporation of the microprocesso�
Timers and Counters
This process increments the various timers for voltage, frequency
and
reconnect,
and
makes the time-out
decisions based on setpoint value&
Self-Tests
On Power Up, the
M-0290
will run through a series of Self-Tests to determine if the hardware and
software will function properly when brought on-lin�
The
M-0290
will also perfor m tests on a low priority basis in its idle time. If no other tasks are
pending, the Self-Test task will continuously rllll.
Failures of any of these tests will result in the
output relay de-energizing.
A
front panel
LED
will flash indicating an error condition. The Self-Test
errors will be described in more detail in the
MAINTENANCE
sectio�
KERNEL
The
nucleus of the operating system is the Kernel.
The
Kernel is comp::>sed of two parts:
1 .
The Scheduler
2.
The
Dispatcher
Scheduler
'!he Scheduler is flagged from an interrupt driver that is waiting for a task to be performed. Status
bi ts
are
set by the scheduler to indicate that a task is pending, and then control is returned to
the
running task. Each task, when started, will run until completion except: the Self-Test task which can
be unconditionally preempted.
Dispatcher
When
a task is completed, control returns to the Dispatcher where it picks up a vector to the pending
task with the highest priority.
The
Self-Test
task is the lowest priority
and
is also permanently pending. Therefore, if the system is
not
busy, the
M-Q290
is constantly checking itself.
Because each task is scheduled on a cycle bY cycle baSis, the operating system
can
be considered to be
operating in real-time.
....
CAUTION:
Do n o t
swap
the M-0298 Memory
Board or the M-0397 EE PROM Board
between PRIDE
m o d els
with suff ix
"A"
and "B" and those
w i t h
suffix "C"
(i.e., between M-0 2 9 0 B and M - 0 2 9 0CI, s i n c e
t h i s w i l l
cause them to
misoperate. Refer
t o
the
DBSIGN CHANGBS
section of
t h i s
manual
f o r
an
explanation of the differences.
-10-
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