4.A2CCPU
:
--------------------
MELSEC-A
4.2.6
Sampling trace
It is
not
possible to check
the
transition of the ON/OFF state
for
bit devices
and
the
data
in
the
word devices with a peripheral device
monitor
function.
The sampling trace function samples
data
from
the
designated
devices at
fixed intervals and stores
the
sample data to
the
sampling
trace area.
Upon execution of
the
STRA instruction,
the
data stored in
the
sampling
trace
area is sampled
for
the
designated
number
of
times
and
the
device
data is latched.
It is possible to monitorthe
data
stored in
the
sampling trace area by reading
it with
the
GPP/PHP/HGP.
I
A2CCPU GPP/PHP/HGP
r-------------------------------------------,
r--------------------------------------,
,
Data of the
Sampling trace
area
,
,
Sample
trace
area
,
designated
*
I
,
,
device
Data in the first
,
Display of
,
1
1
,
sampling
sample
,
,
trace
data
for
Data in the
Reading
2
Device
~2
second
sample
to
GPP/
the
designated
area
3
number
of
Data in the third
PHP/
File
~:
times
,
register
sample
:H
GP
4
-(]
,
Data in the
,
Monitoring
,
,
,
area
fourth sample
~
5
-sampling
,
,
,
,
trace data
,
Data in the fifth
,
,
,
6
,
sample
, ,
,
, ,
,
Data in
the
sixth
i I
,
,
I
,
,
~6
sample
,
,
in:
1 I
I
,
,
,
, ,
,
,
, ,
,
,
Data In the
(n-l)
,
,
n-l
time sample
,
, ,
~--------------------------------------~
Data
in the n
n
time
sample
-----------I
After
the
data
is
sampled
n times, the
:next
data
sample
overwrites the first
data
,
:sample.
~-------------------------------------------~
*
After the execution of the STRA instruction, device
data
sampling is carried out for the
designated
number
of times
and
the
data
in the sampling trace area Is latched.
•
Fig.
4.18
Sampling
Trace
(1) Application
By
using
the sampling trace function, it is possible to shorten
debug-
ging
time by confirming
the
data of
the
designated devices in defined
intervals
during
debugging.
4-30
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