IDEC MICROSmart FC6A Series Ladder Programming Manual

FC6A S ERIES MICROS MART L ADDER P ROGRAMMING M ANUAL FC9Y-B1726 14-1
14: REFRESH INSTRUCTIONS
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)
Valid Devices
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.
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".
When input is on, 1-bit I/O data assigned by source device S1 is refreshed immediately 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 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.
Device Function I Q M R T C D P Constant Repeat
S1 (Source 1) I/O for refresh X X —————— — —
Input Device
Internal
Relay
Input Device
Internal
Relay
Input Device
Internal
Relay
I0 M300 I10 M310 I20 M320
I1 M301 I11 M311 I21 M321
I2 M302 I12 M312 I22 M322
I3 M303 I13 M313 I23 M323
I4 M304 I14 M314 I24 M324
I5 M305 I15 M315 I25 M325
I6 M306 I16 M316 I26 M326
I7 M307 I17 M317 I27 M327
IOREF S1
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IDEC MICROSmart FC6A Series Specifications

General

Brand	IDEC
Model	MICROSmart FC6A Series
Category	Computer Hardware
Language	English