16 - 4 16 - 4
MELSEC-Q
16 COMMUNICATION BETWEEN CPU MODULES IN MULTIPLE PLC
SYSTEM
4): The CPU shared memory occupied with automatic refresh refreshing
becomes the total of setting 1 to setting 4.
The first and last addresses of the CPU shared memory being used
will be displayed in hexadecimals when the number of transmission
points are set.
The PLC for which the transmission points have been set in setting 1
and setting 2 will become the last address of the setting 2 CPU shared
memory. (Up until 811
H
is used for PLC No.1 and PLC No.2, and up
until 821
H
is used for the PLC No.4 in the illustration shown below.)
The PLCs that transmits only setting 1 will become the last address of
the setting 1 CPU shared memory. (PLC No.3 is up to the setting 1
address in the illustration shown below.)
Last address of each CPU share memory (PLC shared memory)
Last CPU device
PLC No.1 transmission range
5): The same number of transmission points must be set for all PLCs on
the multiple PLC system. A "PARAMETER ERROR" occurs if the
number of transmission points for one PLC is different.
(b) CPU devices
The following devices can be used for automatic refresh purposes (other
devices cannot be set up with the GX Developer.)
Settable devices
Caution
Data register (D)
Link register (W)
File register (R, ZR)
• The device in the left column occupies one point for
every transmission point
Link relay (B)
Internal relay (M)
Output (Y)
• Multiples of 0 or 16 are specified for the first number.
• The device in the left column occupies one point for
every transmission point.
1) CPU devices use the total amount of transmission point devices
consecutively from the specified device number to the PLC No.1 to
No.4 in the first set range.
Set a device number so that the amount of transmission point devices
can be secured.
Sixteen times the number of transmission points will be set if a bit
device is specified in the CPU device.
For example, If the total number of transmission points for PLC No.1 to
No.4 is ten, then 160 points will be set between B0 and B9F when the
B0 link relay is specified.