Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 582

• When the subroutine program uses function devices (FX, FY, FD), specify the devices corresponding to the function
devices in (s1) to (s5). The following figure the contents of the devices specified by (s1) to (s5).
X10
P0 FX0
• Before execution of the subroutine program, bit data is transferred to FX and word data is transferred to FD.
• After execution of the subroutine program, the contents of FY and FD are transferred to the corresponding devices.
• Function devices FX and FY are processed in units of bits. Function device FD is processed in units of 4 words. The size of data to be processed varies
depending on the type of the device specified by an argument. The device specified as a function device should be secured for the data size. An error occurs
if it cannot be secured for the data size.
• The following table lists the data sizes of individual types of function devices.
Function device
FX, FY
FD
*2 An error does not occur even if the device number specified by (s1) to (s5) is not a multiple of 16 in bit device digit specification mode.
*3 The data size varies depending on the instruction used.
Ex.
Content of specified device
X0
(1) M0 occupied (The data is transferred to FX0.)
(2) D0 to D3 occupied (The data is transferred to FD1.)
(3) D30 to D33 occupied (The data is transferred to FD2.)
• The XCALL instruction can use (s1) to (s5).
• The number of function devices used in the subroutine program must be identical to the number of arguments of the XCALL
instruction. Also, the types of function devices and XCALL instruction arguments must be the same.
• The device numbers specified by the XCALL instruction arguments must not be overlapping. If they are overlapping,
normal operation cannot be performed.
• Up to 16 XCALL instructions can be nested. Note that the 16-level nesting is the total of the CALL(P), FCALL(P),
ECALL(P), EFCALL(P), and XCALL instructions.
XCALL P0 X0
FEND
END
7 APPLICATION INSTRUCTIONS
580
7.4 Structure Creation Instructions
XCALL
Device
Bit device
When a bit is specified for a word device
When the bit device digit is specified
Word device
XCALL P0
P0
XCALL P10 X10 XCALL
RET RET
P0 X0 D0
D* FD1 K100
*2
M0 D0 D30
(1) (2) (3)
P10 P20
P20 X20
RET
D100
FEND
FD2
RET
Data size
1 point
1 bit
*3
4 words
*3
4 words