Ioref (I/O Refresh) - IDEC MICROSmart FC6A Series Ladder Programming Manual

14: R
EFRESH
Introduction
This chapter describes the refresh instructions that update the status of input contacts, external output , and the current value of
the high-speed counter, to the latest value during a ladder scan.

IOREF (I/O Refresh)

IOREF
*****
Valid Devices
Device
S1 (Source 1)
Only inputs and outputs available on the CPU module can be specified for S1 of the IOREF instruction. However, I14 to I17 and Q14 to Q17 of Plus
CPU module cannot be specified for S1. Input and output numbers for expansion modules or cartridges cannot be designated as S1. For valid device
address ranges, see "Device Addresses" on page 2-1.
Input Device Addresses and Allocated Internal Relays
Internal relays for storage are allocated by input device. For example, when I10 is designated as S1, the latest value of I10 is set
to M310.
Internal
Input Device
Relay
I0
I1
I2
I3
I4
I5
I6
I7
During normal execution of a user program, I/O statuses are refreshed simultaneously when the END instruction is executed 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 immediately.
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 all inputs are read regardless of whether IOREF instruction is programmed when the END instruction is
executed as in the normal scanning, then the filter value has effect as designated in the Function Area Settings. See Chapter 5
"Functions and Settings" - "Input Filter" in the "FC6A Series MICROSmart User's Manual".
I
NSTRUCTIONS
When input is on, 1-bit I/O data assigned by source device S1 is refreshed immediately regardless of the
S1
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 FC6A Series MICROSmart.
When Q (output) is used as S1, the output data in the RAM is immediately written to the actual output
available on the FC6A Series MICROSmart.
Refresh instructions are useful when a real-time response is required in a user program which has a long
scan time. The refresh instruction is most effective when using the refresh instruction at a ladder step
immediately before using the data.
The IOREF instruction can be used with an interrupt input or timer interrupt to refresh data.
Function
I/O for refresh
Input Device
M300 I10
M301 I11
M302 I12
M303 I13
M304 I14
M305 I15
M306 I16
M307 I17
FC6A S MICROS
ERIES
I Q
X X
Internal
Input Device
Relay
M310 I20
M311 I21
M312 I22
M313 I23
M314 I24
M315 I25
M316 I26
M317 I27
L P
MART ADDER ROGRAMMING
M R T C D P
— — — — — —
Internal
Relay
M320
M321
M322
M323
M324
M325
M326
M327
M FC9Y-B1726
ANUAL
Constant Repeat
— —
14-1