Mitsubishi Electric MELSEC iQ-R Series User Manual page 497

Ex.
When mixing the MCFBs of the single axis synchronous control in the Motion module side and the CPU module side
CPU module
PLC program
GearIn1
[Axis3] Master
[Axis4] Slave
[Exec1] Execute
GearIn2
[Axis4] Master
[Axis1] Slave
[Exec2] Execute
(1) When executing the GearInA and GearInB of the Motion module side, the Axis2 and Axis3 of the slave axes run.
(2) When executing the GearIn1 of the CPU module side, the Axis4 runs using the slave axis of the GearInB (Axis3) as the
master axis.
(3) When attempting to execute the GearIn2 of the CPU module side, the Axis1 to Axis4 make a circular reference. Therefore,
an error occurs and the GearIn2 cannot be executed.
• Refresh cycle of I/O variables
The refresh response time of I/O variables for the MCFB of the CPU module side is as shown below.
MCFB call cycle in the CPU module + Buffer memory refresh cycle  2
Errors (including warnings) of the CPU module side during MCFB execution are output as errors of the Motion
module. For the error code output to ErrorID of the MCFB, refer to the following.
Page 27 Error processing
However, when the I/O No. (Page 492 Relevant variable)of the Motion module specified with the MCFB
argument is not correct and the Motion module to execute the FB cannot be specified, the error code is output
to ErrorID only.
ST program
GearInA(Master:=Axis1, Slave:=Axis2, Execute:=exec);
GearInB(Master:=Axis2, Slave:=Axis3, Execute:=exec);
(2)
(3)
Motion module
18 HOW TO CONTROL FROM CPU MODULE
18.2 Using MCFB
18
(1)
495