Mitsubishi Electric MELSEC-Q/L Programming Manual page 485

• When function devices (FX, FY, FD) are used by a subroutine program, specify a device with (S1) to (S5) corresponding to
the function device. The contents to the devices specified by (S1) to (S5) are as indicated below.
• Prior to execution of the subroutine program, bit data is transmitted to FX, and word data is transmitted to FD.
• After the execution of the subroutine program, the contents of FY and FD are transmitted to the corresponding devices.
• The function devices FX and FY are processed in units of bits. The function device FD is processed in units of 4 words. The size of the data to be dealt with
will differ depending on the device specified in the argument. The device specified as a function device should be secured for the data size. An error will occur
if it cannot be secured for the data size.
Function devices
• FX
• FY
• FD
*2 An error will not occur even when the device number specified by (S1) to (S5) is not a multiple of 16 at the digit designation of the bit
device.
[Main routine program]
X0
XCALL P0 M0
• (S1) to (S5) can be used by the XCALL instruction.
• The number of function devices used by a subroutine program must be identical to the number of arguments in the XCALL
instruction. Also, the function device and the type of XCALL argument should be identical.
• The device numbers specified as the arguments of the XCALL instruction should not overlap. If they do overlap, it will not
be possible to obtain accurate calculations.
• Up to 16 nesting levels can be used with the XCALL instruction. However, this 16 levels is the total number of levels in the
CALL(P), FCALL(P), ECALL(P), EFCALL(P), and XCALL instructions.
P0
XCALL P0 X0
XCALL
FEND RET
END
Device
Bit device
When bit designation is made for
word device
When digit designation of a bit device
*2
is used
Word device
D0 D30
Occupies from D30 to D33 (Transfer to FD2).
Occupies from D0 to D3 (Transfer to FD1).
Occupies M0 (Transfer to FX0).
P10 X10 XCALL P20 X20
RET
Data size
1 point
1 bit
4 words
4 words
P20
RET
7 APPLICATION INSTRUCTIONS
7.6 Structure Creation Instructions
Remark

The data size varies depending on
the instruction to be used.
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