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FX3G/FX3U/FX3UC Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
14 Handy Instruction – FNC 60 to FNC 69
14.1 FNC 60 – IST / Initial State
14.1 FNC 60 – IST / Initial State
Outline
This instruction automatically controls the initial state and special auxiliary relays in a step ladder program.
→ For SFC programs and step ladder, refer to Chapter 35.
1. Instruction format
2. Set data
3. Applicable devices
S1: "D.b" is available only in FX3U and FX3UC PLC. However, index modifiers (V and Z) are not available.
S2: S20 to S899 and S1000 to S4095
Explanation of function and operation
• Specify the head input in the operation mode in .
Selector switches in the operation mode occupy eight devices from the head device , and the switch
functions shown in the table below are assigned to each of them.
When X020 is assigned as shown below, it is necessary to set X020 to X024 as rotary switches so that they do not
turn ON at the same time.
It is not necessary to wire unused switches, but they cannot be used for any other purpose because they are
occupied by IST instruction.
• Specify the smallest device number of practical state relays in (for the automatic mode).
• Specify the largest device number of practical state relays in (for the automatic mode).
Operand type Description Data type
Head bit device number of the selector switch in the operation mode Bit
Smallest state relay number of practical state relays in the automatic mode
(<)
Bit
Largest state relay number of practical state relays in the automatic mode
(<)
Bit
Oper-
and
Type
Bit Devices Word Devices Others
System User Digit Specification System User
Special
Unit
Index
Con-
stant
Real
Number
Charac-
ter String
Pointer
XYMTCSD
.b KnX KnY KnM KnS T C D R
U\G
V Z Modify K H E "
"P
333 S1 3
S
2
3
S
2
3
Source Device number (example) Switch function
X020 Individual operation
+ 1
X021 Return to zero point
+ 2
X022 Stepping
+ 3
X023 Cycle operation
+ 4
X024 Continuous operation
+ 5
X025 Zero return start
+ 6
X026 Automatic start
+ 7
X027 Stop
FNC 60
IST
−
Mnemonic Operation Condition
16-bit Instruction
7 steps IST
Mnemonic Operation Condition
Continuous
Operation
32-bit Instruction
S
1
S
D
1
D
1
D
2
D
2
D
1
D
2
S
1
S
S
2
D
1
D
2
Command
input
FNC 60
IST
S
D
1
D
2
S
S
S
S
S
S
S
S
S
S
D
1
D
2