Comparison Uses
There are three types of comparison uses:
- LD (Ladder Diagram)
- AND
- OR
The following compare instructions can be used as a:
- WORD standalone execution condition (LD)
- WORD and execution condition (AND)
- WORD or execution condition (OR)
Instruction Parameters
Supported PLC Series
| PLC-AES | PLC-FB | PLC-ES |
|---|---|---|
| ✓ | ✓ | ✓ |
Supported Data Registers
| M | X | Y | K | L | F | T | C | S | Z | R | Q | D | @D | Constant | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| S1 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| S2 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
Supported Flags
| Flag | Bit | Support |
|---|---|---|
| Error | F11.0 | ✓ |
| Zero | F11.1 | – |
| Carry | F11.2 | – |
Number of Steps
| Steps |
|---|
| 3 |
Operands
| Operand | Description |
|---|---|
| S1 | The first operand. Entries are signed WORD data registers or constants. The signed value range is -32,768 ~ 32,767 (216). The Hexadecimal value range is H0000 ~ HFFFF. Only WORD values will be compared. Only signed or Hexadecimal values will be compared. |
| S2 | The second operand. Entries are signed WORD data registers or constants. The signed value range is -32,768 ~ 32,767 (216). The Hexadecimal value range is H0000 ~ HFFFF. Only WORD values will be compared. Only signed or Hexadecimal values will be compared. |
Notice
Error Flag (F11.0) Notice
The error flag, F11.0, will be ON for one scan when the address of the data register assigned by @D exceeds the range of the data register, D. The range of the data register, D, is dependent on the CPU type.
Ladder Diagram Examples
<
The < instruction compares a WORD value, S1, to another WORD value, S2, and executes if S1 is less than S2.
LD Execution Condition
When the result of the instruction execution of the expression D0 < D2 (62 < 37) is FALSE, the coil, Y1.0, is deenergized.
When the result of the instruction execution of the expression D0 < D2 (12 < 37) is TRUE, the coil, Y1.0, is energized.
Memory Monitor
AND Execution Condition
When the result of the instruction execution of the expression D5 < D7 (3 < 0) is FALSE, and the contact, M0.0 is ON (1), the coil, Y1.1, is deenergized.
When the result of the instruction execution of the expression D5 < D7 (23 < 45) is TRUE, and the contact, M0.0 is ON (1), the coil, Y1.1, is energized.
Memory Monitor
OR Execution Condition
When the result of the instruction execution of the expression D10 < D12 (333 < 22) is FALSE, or the contact, M0.1 is ON (1), the coil, Y1.2, is energized.
When the result of the instruction execution of the expression D10 < D12 (333 < 452) is TRUE, and the contact, M0.1 is OFF (0), the coil, Y1.2, is energized.
Memory Monitor
