690
FX
3G
/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 counters (including 32-bit high speed counters)
Make sure to execute the 32-bit operation (such as "LDD=", "LDD>" and "LDD<") when comparing 32-bit
counters (C200 to C255).
If a 32-bit counter is specified in the 16-bit operation (such as "LD=", "LD>" and "LD<"), a program error or
operation error will occur.
3. Programming of data comparison instructions
When programming in GX Developer, symbols "
≤
" and "
≥
" cannot be input.
Separate "
≤
" into "<" and "=", and separate "
≥
" into ">" and "=" in input.
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) Input "Instruction"
→
"space"
→
"value or device"
→
"space"
→
"value or device".
For an input example, refer to "Instruction input window in GX Developer" shown below.
c) Click the [OK] button.
d) 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>