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 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| D | ✓ | – | ✓ | ✓ | ✓ | – | ✓ | ✓ | – | ✓ | ✓ | ✓ | ✓ | ✓ | – |
Supported Flags
| Flag | Bit | Support |
|---|---|---|
| Error | F11.0 | ✓ |
| Zero | F11.1 | – |
| Carry | F11.2 | – |
Number of Steps
| Steps |
|---|
| 2 |
Operands
| Operand | Description |
|---|---|
| D | The third operand. Entries are only WORD data registers. This is where the value to increase by 1. The signed value range is -32,768 ~ 32,767 (216). The unsigned value range is 0 ~ 65,535 (216-1). The Hexadecimal value range is H0000 ~ HFFFF. |
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.
Signed Overflow
The result data register, D, might overflow:
- The signed value range is -2,147,483,648 ~ 2,147,483,647 (232).
- If the DDEC or DDECP instruction is executed while the value of the data register, D, is -2,147,483,648, the overflow value of the data register, D, will begin at 2,147,483,647.
Ladder Diagram Examples
DDEC
The DDEC instruction decreases the assigned DWORD data register, D, by 1 until the execution condition is OFF.
When the contact, M0.5, is powered ON, the value of the WORD data register, D30, decrements by 1 every scan.
This is the result after deenergizing the coil, M0.5.
Memory Monitor
DDECP
The DDECP one-shot instruction decreases the assigned DWORD data register, D, by 1. Every time this instruction executes, it energizes the output only once.
When the contact, M0.5, is powered ON, the value of the WORD data register, D30, decrements by 1 every scan.
Memory Monitor
