For APOGEE automation stations, individual PPCL programs can be used to replace subroutines. In some cases, time-based statements should not be used in subroutines, and therefore require an individual program.


Five Air Handling Units (AHUs) use the same control strategy. Two possible options for PPCL programming are as follows:

  • Use one PPCL program that contains five duplicate blocks of program code.
  • Use five programs that duplicate one block of program code.

When using multiple programs, the DEFINE statement can be added to each block of code to identify the unique portion of the point names. A section of code might look like the following:






Since the DEFINE statement identifies the AHU that this program controls, there is no need to change the point names throughout the block of code. This block can be copied to each program with changes made only to the DEFINE statement.

For more information, see DEFINE topic.