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18: PROGRAM BRANCHING INSTRUCTIONS

« FC4A MICROSMART USER’S MANUAL » 18-5

IOREF (I/O Refresh)

Applicable CPU Modules

Valid Operands

Only input or output numbers available on the CPU module can be designated as S1. Input and output numbers for expan-

sion I/O modules cannot be designated as S1. For the valid operand number range, see pages 6-1 and 6-2.

Input Operand Numbers and Allocated Internal Relays

Note *: Slim type CPU modules FC4A-D40K3 and FC4A-D40S3 cannot use I10 through I15 as source operand S1; only I0

through I7 can be designated as source operand S1 for the FC4A-D40K3 and FC4A-D40S3.

During normal execution of a user program, I/O statuses are refreshed simultaneously when the END instruction is exe-

cuted at the end of a scan. When a real-time response is needed to execute an interrupt, the IOREF instruction can be used.

When the input to the IOREF instruction is turned on, the status of the designated input or output is read or written imme-

diately.

When the IOREF instruction is executed for an input, the ﬁlter does not take effect and the input status at the moment is

read to a corresponding internal relay.

The actual input status of the same input number is read to the internal input memory when the END instruction is exe-

cuted as in the normal scanning, then the ﬁlter value has effect as designated in the Function Area Settings. See page 5-24.

FC4A-C10R2/C FC4A-C16R2/C FC4A-C24R2/C FC4A-D20K3/S3 FC4A-D20RK1/RS1 & FC4A-D40K3/S3

XXX X X

Operand Function I Q M R T C D Constant Repeat

S1 (Source 1) I/O for refresh X X ————— — —

Input Operand Internal Relay Input Operand Internal Relay Input Operand Internal Relay

I0 M300 I5 M305 I12 * M312

I1 M301 I6 M306 I13 * M313

I2 M302 I7 M307 I14 * M314

I3 M303 I10 * M310 I15 * M315

I4 M304 I11 * M311

When input is on, 1-bit I/O data designated by source operand S1 is refreshed immedi-

ately regardless of the scan time.

When I (input) is used as S1, the actual input status is immediately read into an internal

relay starting with M300 allocated to each input available on the CPU module.

When Q (output) is used as S1, the output data in the RAM is immediately written to the

actual output available on the CPU module.

IOREF

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IDEC FC4A-C16R2 User Manual

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