646
FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
28 Data Comparison – FNC220 to FNC249
28.1 FNC224~230 – LD =, >, <, <>, <=, >= / Data Comparison
Explanation of function and operation
FNC224 to FNC230 are data comparison instructions connected to bus lines.
The contents of
are compared with the contents of
in the binary format, and a contact becomes
conductive (ON) or non-conductive (OFF) depending on the comparison result.
Cautions
1. Negative value
When the most significant bit is "1" in the data stored in
or
, it is regarded as a negative value in
comparison.
• In the 16-bit operation: bit 15
• In the 32-bit operation: bit 31
2. When using 32-bit high speed counters
Make sure to execute the 32-bit operation (such as "LDD=", "LDD>" and "LDD<") when comparing 32-bit high
speed counters (C200 and later).
If a 32-bit high speed counter is specified in the 16-bit operation (such as "LD=", "LD>" and "LD<"), a program
error or operation error is caused.
3. Programming of data comparison instructions
In programming in GX Developer, symbols "
≤
" and "
≥
" cannot be input.
Separate "
≤
" into "<" and "=", and separate "
≥
" into ">" and "=" in input.
When inputting a data comparison instruction in a circuit diagram, use the symbol "-[ ]-".
The input procedure is described below:
Operating procedure
a) Display the circuit program edit window, and put the cursor in a position where a data comparison
instruction is to be used.
b) Select the coil symbol "-[ ]-".
c) Input "Instruction"
→
"space"
→
"value or device"
→
"space"
→
"value or device".
For an input example, refer to "Instruction input window in GX Developer" shown below.
d) Click the [OK] button.
e) Input other contacts and coil drive units consecutively.
Instruction input window in GX Developer
FNC No.
16-bit instruction
32-bit instruction
ON condition
OFF condition
224
LD=
LDD=
=
≠
225
LD>
LDD>
>
<=
226
LD<
LDD<
<
>=
228
LD<>
LDD<>
≠
=
229
LD<=
LDD<=
<=
>
230
LD>=
LDD>=
>=
<
S
1
S
2
S
1
S
2
S
1
S
2
S
1
S
2
S
1
S
2
S
1
S
2
S
1
S
2
S
1
S
2
S
1
S
2
S
1
S
2
S
1
S
2
S
1
S
2
S
1
S
2
S
1
S
2
<Input example for 16-bit operation>
<Input example for 32-bit operation>
Содержание FX3U Series
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