User Guide

Program Methodology—Converting a Sequence of Operation into
Program Code
Siemens Building Technologies, Inc. 1-107
Pseudocode
Pseudocode is information written in a non-syntactical manner to
document program code. Programmers often use pseudocode to
quickly organize their ideas before writing the code. After the code is
written, the pseudocode becomes a reference that describes the
functionality of the program.
For example, when solving a programming problem, you might start
by asking yourself questions about what is to be accomplished. As
you define what must be accomplished, you can create a logical list
of the steps the program should perform. You might create a
pseudocode list with the following items:
1. Check mixed air temperatures
2. Check outside air temperatures
3. Open/close dampers as needed
4. Start/stop fans
From this list, you would begin writing program code to accomplish
these functions.
Solving a Programming Problem
When you first start programming in PPCL, you should have a
problem-solving method. The time you spend organizing your ideas
in advance helps prevent program logic flaws.
The following problem-solving example begins with the sequence of
operation, continues through the testing, and ends with documenting
the final program code.
APOGEE PPCL User’s Manual
1-108 Siemens Building Technologies, Inc.
Developing a Sequence of Operation
1. Read through the problem to gain an understanding of what the
sequence of operation is asking you to do.
If you have a large sequence of operation, you may want to
break it down into smaller, manageable sections.
2. Determine modes of operation that will be used during system
operation. Examples of operational modes are:
• Day mode
• Night mode
• Emergency mode
Defining the modes of operation helps you design the code in a
highly organized manner.
3. Identify specific controls and procedures that need program
code. Look for key phrases, such as:
"This system must control..."
"Will perform..."
"Cycle..."
"Calculate..."
Each of these phrases becomes some type of control for which
you will write PPCL code.
4. Classify each type of control as a mode of operation.
5. Use a decision table or pseudocode to determine the order in
which the tasks should be performed.
Either of these methods is acceptable, or you may find another
method to organize the tasks. Use the method that is the easiest
and most helpful for you.