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SECTION
1.
FUNCTIONAL MODES
1.1
TABLES
-*1,*2,
AND *3
MODES
Data acqu
and processing
functions are
controlled b]l instructions
contained in program
tables.
can be separated into
2
tables,
each having its own programmable
execution
inlerval.
A third
table
is
available
for
programming subroutines
which may be called
interrupt.
access
T
*1
and
*2 Modes are used to
'l
and
2.
The "3 Mode is used to
access
Table
3.
When
a
table
is
first entered, the
display
the
table number
in
the lD Field
and
00
in
Data
Field.
Press A and the 21X
will
to
the execution
interval.
lf
there
is
an existing
instruction
in
the
table, enter
an
number prior to A and the
21X will
directly to
the instruction (e.9.,
5
will
to the
fifth instruction in the
table).
INTERVAL
The
interval is
entered in units of
seconds as
0.0125....
1
seconds, in multiples of 0.0125
0.1 .....655q seconds, in multiples of 0.1 second
Intervals
leds
than 0.1 second are allowed
in
Table
1
onlf.
Execution
of
the
table is repeated
at
the rate (etermined by this
entry.
The table
will not be dxecuted
if
0
is
entered. Values
less
than 0.1
ard rounded to the nearest even
multiple of
0.0125.
lf
the Interval
is
0.1
or
greater, the 21X
will
not
allow entry of digits
beyond 0.1.
The
sample rate for a 21X measurement
is
the
rate at which
the measurement instruction can
be
executed (i.e., the measurement made,
scaled with
the instruction's multiplier and offset,
and
the
resUlt
placed
in lnput Storage).
Additional
processing requires extra
time. The
throughput
fate
is
the rate at which
a
measurem{nt can be made and the resulting
value
stored in Final
Storage. The
maximum
throughput
]rate
for
fast single ended
measurem$nts (other than with
the burst
measurement)
is
256 measurements per second
(16
measurements repeated
16
times per
second).
lf
the specified execution interval for
a
table
is
less
than the time required to process that table,
the 21X overruns the execution interval, finishes
processing the
table and waits for the next
occurrence of the
execution interval before
again initiating the
table (i.e., when the
execution interval is up and the table
is still
executing, that
execution
is
skipped).
Since no
advantage is gained
in
the rate of execution with
this situation,
it
should be avoided by specifying
an execution interval adequate for the table
processing time.
NOTE: Whenever
an overrun
occurs, decimal points are displayed
on both sides
of
the sixth digit
of
the
21X
display (e.9.,
L
O.G.
in
the *0
Mode).
When
the Output Flag
is
set high, extra time
is
consumed
by
final output
processing. The
execution interval may be exceeded
at
this time
only,
which may be
acceptable.
For example,
suppose it
is
desired
to measure every
0.1
seconds and
output processed data every ten
minutes. The
processing
time of the table
is
less
than 0.1 seconds except when output
occurs (every 10 minutes). With
finaloutput
processing the
time required is
1
second.
With
the
execution interval set at 0.1 seconds, and
a
one
second lag between samples once every
10
minutes,
10
measurements
out of 6000
(.17o/o)
are
missed:
an acceptable
statistical error for
most populations.
1.1.2 SUBROUTINES
Table 3 is used to enter subroutines which may
be
called
with Program Control Instructions
in
Tables
1
and 2 or other
subroutines. The group
of instructions which
form a subroutine starts
with lnstruction 85, Label Subroutine, and ends
with Instruction 95, End. (Section
12)
1.1.1
1-1
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