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FX3S/FX3G/FX3GC/FX3U/FX3UC Series
Programming Manual - Basic & Applied Instruction Edition
7 Basic Instruction
7.13 SET, RST
Cautions on using RST instruction for a jumped program, subroutine program or interrupt program
When RST instruction for a timer or counter is executed in a jumped program, subroutine program or interrupt
program, the timer or counter may be kept in the reset status and the timer or counter may be disabled.
For details, refer to the following sections:
→ For a jumped program, refer to Subsection 8.1.1.
→ For a subroutine program, refer to Subsection 8.2.1.
→ For an interrupt program, refer to Subsection 36.2.3.
3. Indexing
*1
Devices used in SET and RST instructions can be indexed with index registers (V)(Z).
(State relays (S), special auxiliary relays (M), 32-bit counters, "D.b", and word devices cannot be indexed.)
V0 to V7 and Z0 to Z7 are available for indexing.
When a used device is an input (X) or output (Y),
the value of an index register (V or Z) is converted
into octal, and then added.
Example: When Z0 is "20", Y024 turns ON or
OFF.
*1. This function is supported only in FX
3U/FX3UC PLCs.
4. Bit specification of a data register (D)
*1
A bit in data register (D) can be specified as a device used in SET or RST instruction.
When specifying a bit in data register, input "."
after a data register (D) number, and then input a
bit number (0 to F) consecutively.
Only 16-bit data registers are available.
Specify a bit number as "0, 1, 2, ... 9, A, B, ... F"
from the least significant bit.
Example: In the example shown on the left, when
X000 turns ON once, the bit 3 of D0
turns ON. When X001 turns ON, the bit
3 of D0 turns OFF.
*1. This function is supported only in FX
3U/FX3UC PLCs.
Caution
When SET and RST instructions are executed for an output relay (Y) in the same operation, the result of the
instruction located nearest the END instruction (which specifies the end of program) is output.
Errors
• When an I/O number used in SET or RST instruction does not exist due to indexing, M8316 (Non-existing I/O
specification error) turns ON.
• When the device number of a device (M, T or C) other than I/O used in SET or RST instruction does not exist due
to indexing, an operation error (error code: 6706) occurs.
Circuit program List program
LD
SET
LD
RST
0000
0001
0004
0005
X000
Y000Z0
X001
Y000Z0
X000
Y000Z0SET
X001
Y000Z0RST
Circuit program List program
LD
SET
LD
RST
0000
0001
0004
0005
X000
D0.3
X001
D0.3
X000
D0.3SET
X001
D0.3RST