Rockwell Automation 1794-Lxxxx PhaseManager User Manual
Page 63
Publication LOGIX-UM001B-EN-P - April 2010
63
Equipment Phase Instructions (PSC, PCMD, POVR, PFL, PCLF, PXRQ, PRNP, PPD, PATT, PDET)
Appendix A
States, Substates, and Commands of an Equipment Phase
Guidelines for Using the PCMD Instruction
state
substate
Use the auto pause, pausing, and paused substates to test and debug a state routine. The
substates require the Equipment Phase Paused (PPD) instruction to create breakpoints in your logic.
The auto pause, pause, and resume commands let you step through the breakpoints.
command
Some states need a command to go to the next state. If the
equipment phase is in the idle state, a start command
transitions the equipment phase to the running state. Once
in the running state, the equipment phase executes its
running state routine.
Other states use a Phase State Complete (PSC) instruction
to go to the next state. If the equipment phase is in the
holding state, a PSC instruction transitions the equipment
phase to the held state. Once in the held state, the
equipment phase needs a restart command to go to the
restarting state.
Guideline
Details
Limit execution of a PCMD instruction
to a single scan.
Limit the execution of the PCMD instruction to a single scan. Each command applies to only a
specific state or states. Once the equipment phase changes state, the command is no longer
valid. To limit execution:
• execute the PCMD instruction within a P1 Pulse (Rising Edge) or P0 Pulse (Falling Edge)
action.
• place a one shot instruction before the PCMD instruction.
• execute the PCMD instruction and then advance to the next step.
Determine if you need to take
ownership of the equipment phase.
As an option, a program can own an equipment phase. This prevents another program or
FactoryTalk Batch software from also commanding the equipment phase.
If you use
Then
FactoryTalk Batch software to also run
procedures (recipes) within this controller
Before you use a PCMD instruction, use
an Attach to Equipment Phase (PATT)
instruction to take ownership of the
equipment phase. See
multiple programs to command the same
equipment phase
none of the above
There is no need to own the equipment
phase.