Mitsubishi Electric GOT2000 Series Connection Manual page 150

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2.8 MELSEC-FX
POINT POINT POINT
(1) Precautions when using the buffer memory
• When the power supply of the special block or special module is turned off, the contents of
the buffer memory are initialized, except for some keeping areas.
• When the buffer memory is monitored by the GOT, the PLC scan time may increase
instantly.
• Use the 16 bit specification for the buffer memory of 16 bit data. Use the 32 bit specification
for the buffer memory of 32 bit data. If using the 16 bit specification for a buffer memory of
32 bit data, monitoring and writing may not be executed normally.
For the data size of each buffer memory, refer to the following.
➠
User's Manual of the special block or special module
• When reading from/writing to the special block or special module by interrupt processing of
the sequence program, monitoring/writing from GOT to the buffer memory may not be
executed normally.
(2) How to select a keyword protection level
For equipment that are allowed to operate the FX PLC online, 3 levels of protection level can
be set.
When monitoring or changing settings by any online equipment is required, set a keyword
referring to the following.
(a) When setting the keyword only
Select a protection level by the initial letter of the keyword.
All operation protect: Set a keyword with the initial letter "A", "D" to "F", or "0" to "9".
Incorrect write/read protect: Set a keyword with the initial letter "B".
Incorrect write protect: Set a keyword with the initial letter "C".
(b) When setting the keyword and 2nd keyword
Select a protection level by [Registration condition].
(3) Monitoring availability at each keyword protection level
The following shows the device monitoring availability at each keyword protection level.
Item
Monitoring devices
T, C set
value and
file register
(D1000
Changing
and the
devices
following)
Other than
above
*1 When the T, C set values are specified indirectly, changing devices is available.
(4) Difference between all online operations prohibition and all operations prohibition
When specifying all online operations prohibition, displaying devices and inputting data with
programming tools or GOT are all prohibited.
When all operations are prohibited, displaying devices and inputting data with the GOT are
enabled while all operations using programming tools are prohibited.
When registering the keyword only
All Incorrect Incorrect
operation write/read write
protect protect protect
*1 *1
When registering the keyword
and 2nd keyword
All online Read/
operation write
protect protect
*1
Keyword
not
registered
or
Write
protection
protect
cancelled