Rice Lake 720i Programmable Indicator/Controller - Installation Manual - Manual (Page 87)

Using ProAction PCEE 81
9.0 Using ProAction PCEE
Note
When working with this chapter, the PCE Version software must be installed.
In addition to Revolution III ® , the 720i is supported by two additional applications that extend its capabilities for
batch control and database management. ProAction PCEE, or Process Control Engine Editor, provides functions
similar to setpoint configuration for
720i -based batch control. ProAction DBE, the database editor, is a tool for
creating, editing, and managing databases in the 720i . Both applications are included on the 720i Toolkit CD.
PCEE is developed around a step, condition, and action philosophy.
A step contains conditions and actions (see example below). A condition is a situation that must be met to
accomplish the true actions. If the conditions are not met, the false actions are executed. When a transition happens
to the condition, the corresponding true or false actions will be executed. All actions will all be executed even after
a pause.
Example:
The condition could be a Weight Compare

(Gross is trip higher than 1000).
The false action could be to turn on a digital output

(Digital I/O 1 is On, since weight is below 1000).
The true action could be to turn off the digital output

(Digital I/O 1 is Off, since the weight is above 1000).
Steps are typically sequenced one after another. This is accomplished by actions that allow a step to deactivate
itself and to activate other steps. The true action list for the above example is:
• Digital I/O is Off
• Deactivate Step 1
• Activate Step 2
When a step is enabled, the actions will only be executed once until a condition transitions. This transition can be
from true to false, or from false to true. Deactivated steps are not evaluated until activated by another step. When a
step is activated (enabled), either the true or false actions will be executed.
Writing a PCE Process
The first step to writing a PCE Process is to decide what small routines are to be built into the total process. This
could include steps for:
• The batch process
• Entering a new target weight
• Printing the weight
• Other functions relating to the process
Before the steps are created, you should write out the sequence of the process/functions on a worksheet. Then,
consider the following in working through the details:
• The softkeys or inputs/outputs required
• The steps “enabled” at power-up (at least one is required to start the process)
• Determine the condition to evaluate for each step, and the actions
• What the print formats are going to be
• What database tables need to be created and the data stored in each field
As each step is built, keep in mind the True, False, and Pause lists execute the actions in the order they are listed,
meaning an action such as “print” should precede an action such as “tare.”
Steps for a particular routine can be built and tested using just that routine, and when all of the smaller routines are
complete, a final merge can be done to finalize the process.