Phase Paused (PPD)
This instruction applies to the Compact GuardLogix 5370 and Compact GuardLogix 5380, CompactLogix 5370, CompactLogix 5380, and CompactLogix 5480, ControlLogix 5570 and ControlLogix 5580, and GuardLogix 5570 and GuardLogix 5580 controllers.
TIP:
When using this instruction with ControlLogix redundancy system, outputs controlled by this instruction may not be bumpless during redundancy switchover, if the instruction and phase program are not scheduled in the highest priority task.
Pausing an equipment phase requires configuring break points by coding a PPD instruction in a phase's state routine logic. The phase state routine pauses when the PPD instruction executes and the phase receives a command to pause at its next opportunity.
This is a transitional instruction. Follow these steps when using it:
- In ladder logic, insert an instruction to toggle the rung-condition-in from false to true each time the instruction should execute.
- In a Structured Text routine, insert a condition for the instruction to cause it to execute only on a transition.
Three operator commands relate to the pause functionality:
- Pause: The Pause command enables or disables pausing execution of the phase when the next PPD instruction executes. The Pause command toggles the PauseEnabled bit ON (1) or OFF (0).
- AutoPause:The AutoPause command enables or disables automatically enabling pausing the phase after processing a Resume command. The AutoPause command toggles the AutoPauseEnabled bit ON (1) or OFF (0).
- Resume:The Resume command directs the firmware to resume executing the phase state routine logic. Resume sets the PauseEnabled and Paused bits OFF (0).
The Pause substate uses these three bits:
- PauseEnabled: The PauseEnabled bit maintains the status of processing a Pause command. This is bit 0 of the Pause substate.When Paused is ON (1), execution of a PPD instruction pauses execution of the state routine's logic. This bit updates when it receives a Pause command (toggling the bit's value). Additionally, a Resume command sets PauseEnabled OFF (0), if the AutoPauseEnabled bit is ON (1).
- AutoPauseEnabled: The AutoPauseEnabled bit maintains the status of automatically enabling pausing immediately after a Resume command. This is bit 2 of the Pause substate.This bit updates when it receives an AutoPause command (toggling the bit's value). When AutoPauseEnabled is ON (1) and the phase is Paused, the Resume command leaves PauseEnabled ON (1).
- Paused: The Paused bit maintains the pause-state of the phase, Paused (1) or not-Paused (0). This is bit 1 of the Pause substate. The Paused bit also disables the rest of the rung (RLL), it does not terminate or suspend the execution of the routine.This bit is only set by the phase's firmware. When the PauseEnabled bit is ON, execution of a PPD instruction causes the Paused bit to be set to Paused (1) and firmware pauses execution of the phase state routine suspends. A Resume command sets the Paused bit to not-Paused (0) and the phase executes its logic.
Available Languages
Ladder Diagram
Function Block
This instruction is not available in function block.
Structured Text
PPD( );
Operands
Ladder Diagram
None
Structured Text
None
Enter the parentheses ( ) after the instruction mnemonic, even though there are no operands.
Guidelines for using the PPD Instruction
Guideline | Details | |
---|---|---|
Organize logic as a series of steps. | PPD instructions (breakpoints) are easiest to use if the logic moves through defined steps, such as a state machine or SFC.
| |
Do not use a PPD instruction as a temporary end of the routine. | Even when an equipment phase pauses, it continues to execute all its logic.
| |
Use PPD instruction to pause at the same breakpoint over several scans. | When the PauseEnabled bit is TRUE, an equipment phase goes to Paused at the first PPD instruction whose conditions are true. If the PPD instruction executes over several scans, the equipment phase may continually pause at the same breakpoint. | |
Make sure only 1 PPD instruction at a time is true. | A PPD instruction does not have a control tag to remember whether it executed.
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Choose the substate to use. | PPD instructions (breakpoints) work only when the equipment phase PauseEnabled bit is True. | |
To pause at: | Give this command: | |
Each true breakpoint | Auto Pause | |
First true breakpoint | Pause |
Affects Math Status Flags
No
Major/Minor Faults
A major fault occurs if: | Fault type | Fault code |
---|---|---|
Instruction is called from outside an Equipment Phase program. | 4 | 91 |
If an Add-On Instruction uses a PPD instruction, and a non-equipment phase program calls the Add-On Instruction,
Logix Designer
gives a warning. Check the Add-On Instruction for this instruction to disallow it. See Index Through Arrays
for operand-related faults. Execution
Condition/State | Action Taken |
---|---|
Prescan | No action taken. |
Postscan | No action taken. |
EnableIn is false | No action taken. |
EnableIn is true | The instruction executes. |
Example
Ladder Diagram
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