Watchdog Timer
Instruction Parameters
Supported PLC Series
| XPnA/1R | XPnB | XPnE | XPnF | CP3A/B/P/U CP4A~D/U | CPnE | CPnF | BP | PLC-S |
|---|---|---|---|---|---|---|---|---|
| ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
Supported Data Registers
| M | X | Y | K | L | F | T | C | S | Z | R | Q | D | @D | Constant | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| S | - | ✓ | ✓ | - | - | - | - | - | - | - | - | - | - | - | - |
| n | ✓ | - | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | - | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
Supported Flags
| Flag | Bit | Support |
|---|---|---|
| Error | F11.0 | ✓ |
| Zero | F11.1 | - |
| Carry | F11.2 | - |
Number of Steps
| Steps |
|---|
| 3 |
Operands
| Operand | Description |
|---|---|
| S | The first operand. Entries are only BOOL data registers. This is the I/O device input/output to force refresh. |
| n | The second operand. Entries are WORD data registers or constants. This is the number of I/O devices to refresh. |
Notice
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.
CPU Behavior
When the RFS or RFSP instruction is executed with CPU types such as the PLC-S, BP, XPnA/1R, CP3A/B/P/U and CP4A~D/U, the all I/O devices are refreshed regardless of the devices and values assigned to the operands.
Instruction Behavior
The RFS and RFSP instructions behave as follows:
- The RFS and RFSP instructions force an I/O refresh during the execution of a scan program.
- The number of I/O devices is specified by n.
- The specified I/O devices starting from the data register, S, are refreshed.
- When the RFS or RFSP instruction is executed in the progress of a scan cycle, the I/O refresh is executed forcibly during the program execution.
- Below is a scan cycle:
- Below is a scan cycle:
- Normally, external I/O refreshing is conducted after the execution of the END instruction, so it is not possible to output a pulse signal to an external actuator during a scan.
- However, when the RFS or RFSP instruction is executed, the corresponding I/O devices are refreshed forcibly during the program execution.
- This means that an output pulse signal to an external source during a scan is possible.
- However, when the RFS or RFSP instruction is executed, the corresponding I/O devices are refreshed forcibly during the program execution.
- THE RFS and RFSP instructions operate only on the I/O devices assigned to the local base.
