16  MULTIPLE CPU SYSTEM FUNCTION
16.4  Data Communication Between CPU Modules
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When there exists a CPU module for which "Disable" is set to "Fixed Scan Communication Function", if the 
send area of the fixed scan communication area is set to a CPU module for which "Disable" is set to "Fixed 
Scan Communication Function" (unspecified) in the parameter setting on the host CPU module, no error is 
generated because the unspecified CPU module is considered as a reserved one for future configuration.
Example: in four module configuration with the host CPU module is set to CPU No.1 and the fixed scan 
communication function of CPU No.4 set to "Disable"
(1) Since the setting does not allow fixed scan communication, this CPU module does not send data to the 
other CPU modules although send areas have been reserved. This CPU module does not receive data from 
the other CPU modules.
(1)
Send area of 
CPU No.1
Send area of 
CPU No.2 
(Receive area of 
CPU No.1)
Send area of 
CPU No.3 
(Receive area of 
CPU No.1)
Send area of 
CPU No.4 
(Receive area of 
CPU No.1)
Send area of 
CPU No.2
Send area of 
CPU No.3
Send area of 
CPU No.4
Fixed scan 
communication area
Fixed scan 
communication area
CPU No.1 
(host CPU module)
CPU No.2 
(another CPU module)
Setting:  
  Establish fixed scan 
  communication.
Setting:  
  Establish fixed scan 
  communication.
Setting:  
  Establish fixed scan 
  communication.
Setting:  
  Do not establish fixed scan 
  communication.
Send area of 
CPU No.1
Send area of 
CPU No.2
Send area of 
CPU No.3
Send area of 
CPU No.4
Fixed scan 
communication area
CPU No.3 
(another CPU module)
Send area of 
CPU No.1
Fixed scan 
communication area
CPU No.4 
(another CPU module)