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 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | ✓ | ✓ | ✓ | ✓ | ✓ | – |
| D | ✓ | – | ✓ | ✓ | ✓ | – | – | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | – |
| B | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| n | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
Supported Flags
| Flag | Bit | Support |
|---|---|---|
| Error | F11.0 | ✓ |
| Zero | F11.1 | – |
| Carry | F11.2 | – |
Number of Steps
| Steps |
|---|
| 6 |
Operands
| Operand | Description |
|---|---|
| S1 | The first operand. Entries are WORD data registers or constants. This is the starting data register for the first range of n data registers to compare to S2. This requires n data registers. The signed value range is -32,768 ~ 32,767 (216). The Hexadecimal value range is H0000 ~ HFFFF. |
| S2 | The second operand. Entries are only WORD data registers. This is the starting data register for the second range of n data registers to compare to S1. This requires n data registers. The signed value range is -32,768 ~ 32,767 (216). The Hexadecimal value range is H0000 ~ HFFFF. |
| D | The third operand. Entries are only WORD data registers. This is where the comparison result is saved. This could require more than 1 WORD data register. |
| B | The fourth operand. Entries are BOOL data registers or constants. This is the starting bit address to save the comparison results to. |
| n | The fifth operand. Entries are WORD data registers or constants. This is the amount of data registers to compare starting at S1 and S2. |
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
BK<
The BK< instruction compares n number of WORD data registers starting at S1 to n number of WORD data registers starting at S2. For each data register in the range S1 ~ Sn that is less than each data register in the range S2 ~ Sn, the corresponding bit in the data register D, starting at bit number B, will turn ON (1).


- The BK< instruction will compare the following expressions for a true or false value:
- D25 < D30 → -1,300 < -1,300
- D26 < D31 → 1,642 < 5,613
- D27 < D32 → -1,200 < -2,500
- D28 < D33 → 9,861 < 10,250


- When the open contact, M0.0, is powered ON (1), the values of the data registers are compared.
- D25 < D30 → -1,300 < -1,300 (FALSE → D35.1 = 0)
- D26 < D31 → 1,642 < 5,613 (TRUE → D35.2 = 1)
- D27 < D32 → -1,200 < -2,500 (FALSE → D35.3 = 0)
- D28 < D33 → 9,861 < 10,250 (TRUE → D35.4 = 1)
Memory Monitor

BK<P
The BK<P one-shot instruction compares n number of WORD data registers starting at S1 to n number of WORD data registers starting at S2. For each data register in the range S1 ~ Sn that is less than each data register in the range S2 ~ Sn, the corresponding bit in the data register D, starting at bit number B, will turn ON (1). Every time this instruction executes, it energizes the output only once.


- The BK<P instruction will compare the following expressions for a true or false value:
- D40 < D45 → -100 < 100
- D41 < D46 → 4,561 < -4,512
- D42 < D47 → 7,822 < 11,250


- When the open contact, M0.1, is powered ON (1), the values of the data registers are compared.
- D40 < D45 → -100 < 100 (TRUE → D50.2 = 1)
- D41 < D46 → 4,561 < -4,512 (FALSE → D50.3 = 0)
- D42 < D47 → 7,822 < 11,250 (TRUE → D50.4 = 1)
Memory Monitor

