Mitsubishi Electric MELSEC-Q/L

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7 APPLICATION INSTRUCTIONS

7.6 Structure Creation Instructions

479

• When function devices (FX, FY, FD) are used by a subroutine program, specify a device corresponding to the function

device with (S1) to (S5).

*1 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]

• (S1) to (S5) can be used with the EFCALL (P) instruction.

• The number of function devices used by subroutine programs must be identical to the number of arguments used by the

EFCALL (P) instruction. Further, the function devices should be identical to the types of arguments used by the EFCALL (P)

instruction.

• Up to 16 levels of nesting can be used with the EFCALL (P) instruction. However, this 16 levels is the total number of levels

in the CALL(P), FCALL(P), ECALL(P), EFCALL(P), and XCALL instructions.

• 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 Device Data size Remark

•FX

•FY

Bit device 1 point 

When bit designation has been made

for word device

1 bit

• FD When digit designation of a bit device

is used

4 words The upper 2 words of FD become 0.

Word device 4 words 