Data Consistency Function; Setting Method; Access Control On Input Data Areas - Mitsubishi Electric MELSEC iQ-R Series User Manual

1.2

Data Consistency Function

This function ensures the consistency of input data and output data to be transferred by the I/O data exchange for each IO
device.
Data inconsistency is prevented by using the buffer memory and performing interlocks on the access to the input areas or
output areas between the CPU module and the RJ71PN92.

Setting method

Enable the bit of 'Data consistency setting area' (Un\G17033 to Un\G17040) corresponding to the IO device that exchanges
the I/O data to use this function.
Page 146 Data consistency setting area

Access control on input data areas

For the access control on input data areas, use the following buffer memory areas and perform interlocks.
• 'CPU to PN handshake flag (data consistency setting input area)' (Un\G17041 to Un\G17048)
• 'PN to CPU handshake flag (data consistency setting input area)' (Un\G17128 to Un\G17135)
Combinations of handshake flags
When the data consistency function is enabled, whether or not to read input data areas is determined depending on the
combination of the settings of the buffer memory areas.
The following table lists the combinations of the settings of the buffer memory areas.
'CPU to PN handshake
flag (data consistency
setting input area)'
(Un\G17041 to
Un\G17048)
OFF
OFF
ON
ON
Control by programs
Create a program to control data in the following order.
1.
Compare the bits of 'CPU to PN handshake flag (data consistency setting input area)' (Un\G17041 to Un\G17048) and
'PN to CPU handshake flag (data consistency setting input area)' (Un\G17128 to Un\G17135) corresponding to the IO
device that exchanges the I/O data.
2.
Read data from the input data area of the specified IO device when one of the bits is in the off state and the other is in the
on state.
3.
After the data is read, reverse the on/off state of the bit of 'CPU to PN handshake flag (data consistency setting input
area)' (Un\G17041 to Un\G17048) corresponding to the IO device that exchanges the I/O data. (Off  On or On  Off)
1 FUNCTIONS
20
1.2 Data Consistency Function
'PN to CPU handshake Read
flag (data consistency inhibited/
setting input area)' enabled
(Un\G17128 to
Un\G17135)
OFF Read
inhibited
ON Read
enabled
ON Read
inhibited
OFF Read
enabled
Operation of the RJ71PN92
• The values in the input data area of the specified IO device are
updated to the values in the internal memory of the RJ71PN92.
• After the data is updated, the bit of 'PN to CPU handshake flag
(data consistency setting input area)' (Un\G17128 to
Un\G17135) corresponding to the IO device that exchanges
the I/O data turns on.

• The values in the input data area of the specified IO device are
updated to the values in the internal memory of the RJ71PN92.
• After the data is updated, the bit of 'PN to CPU handshake flag
(data consistency setting input area)' (Un\G17128 to
Un\G17135) corresponding to the IO device that exchanges
the I/O data turns off.

Control by
programs

Page 20
Control by
programs
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Control by
programs