Sampling Trace - Mitsubishi Electric MELSEC-A Series User Manual

4.A2CCPU
:
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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 monitor the 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.
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