Reading And Writing The Buffer Memory (Using The Buffer Memory Automatic Update Function); Outline - Mitsubishi MELSEC AJ65BT-R2 User Manual

5 PRELIMINARY INFORMATION
5.6 Reading and writing the buffer memory (using the buffer memory automatic update
function)

5.6.1 Outline

Programmable controller CPU
TO(RITO)
FROM(RIFR)
The methods for reading and writing the R2 buffer memory using the buffer memory
automatic update function is described in this section.
When the buffer memory automatic update function is used, data can be read and
written using the FROM/TO command, so the sequence program can be simplified.
With the buffer memory automatic update function, if a cause of data communication
between the R2 buffer memory automatic update area and master station automatic
update buffer is generated, the data is automatically exchanged, and the data in the
corresponding area of each station is updated.
Refer to section 5.6.2 for details on each area and the update timing.
• Reading : The master station buffer memory corresponding to the buffer memory
to be read is read out with the FROM/RIFR command.
• Writing : Data is written to the master station buffer memory corresponding to
the buffer memory to be written in using the TO/RITO command.
1st station's
automatic
update
buffer
(1) Changing the bank when using the A Series master module
When using the A Series master module (AJ61BT11/A1SJ61BT11), the master
station's automatic update buffer will be "bank 2".
Thus, create the program so that the bank is changed to "bank 2" when reading
to or writing from the automatic update buffer, and so that "bank 0" is returned to
after the reading/writing is completed.
When using the RITO/RIFR commands dedicated for the AnSHCPU, the bank
will not be changed automatically by the commands. Thus, the bank must be
changed by the user.
Refer to section 5.2 for details on changing the bank.
(2) Setting the timeout
By setting the following buffer memory in the R2, a timeout can be set for
exchanging data between the R2 and master station when using the buffer
memory automatic update function.
(a) Transient timeout designation area (
0: 5 seconds
Master station
Buffer memory
(automatic update area)
Status storage area
Transmission area
Automatic update
Monitor transmission area
2nd station automatic
update area
If a cause of automatic update, explained in section 5.6.2,
occurs, the area is automatically updated.
1 to 360: designated time (seconds)
5 - 18
MELSEC-A
R2 (1st station)
Buffer memory
Status storage area
Transmission area
Monitor transmission area
)
R 2 105
H