COMPACTLOGIX PROJECT STRUCTURE

PROJECT

Everything required for the program to function is contained within the project.

CONTROLLER ORGANIZER PANEL

TASKS

The default project provides single task.

A project can have up to 6-tasks. 1769-L32x processor.

task holds information necessary to schedule the programs execution and determines the execution priority for one or more programs.

TASKS

Continuous: The continuous task runs all of its programs, and then it starts again (continuously, you might call it). It’s quite normal to put most or all of your logic in the continuous task. Example; Fill a tank to its maximum value and then open a drain valve

Periodic: Periodic tasks are scheduled to run at a pre-defined period, such as every 100 ms. Example; Read the thickness of a paper roll every 2 sec.

CONTROLLER ORGANIZER TREE

By default, RSLogix 5000 has already created a continuous task called MainTask. Note the little circular arrow on MainTask – that means it’s a continuous task.

Inside MainTask, it’s created a program called MainProgram, and it has one ladder logic routine called MainRoutine inside.

It also has a place for program specific tags. These are tags that are only visible to logic inside of this program

PROGRAM

Program: Each task requires at least one program. A task can have up to 32-programs. Only one program can execute at-a-time.

Main Routine: When a program executes the main routine executes first. The main routine is used to call(execute) other routines in the program (subroutines). The main routine in RSLOGIX 5000 is the same as LAD 2 in RSLOGIX 500.

Routines: Routines are where the executable code resides. Routines can be written in: Ladder Logic, Sequential Function Chart, Function Block Diagram, and Structured Text. Routines are used to keep programs organized.

TAG BASED MEMORY STRUCTURES

Tag based memory structures are what most new generation PLCs use. A tag is a friendly name for a memory location. This tag name also has a data type assigned.

TAGS

The Scope of the tag defines if a tag is global (controller tags) and therefore available to all programs or local (program tags) to a select program group.

Controller Tags are available to all programs.

Program Tags are isolated from other programs.

COMPACTLOGIX TAG BASED MEMORY STRUCTURE

COMPACTLOGIX TAG BASED MEMORY STRUCTURE

Tag names should be assigned that are descriptive to the data being stored in them. Example of tag names could be: Start_PB, Vessel01MixMotor, furnaceTemp.

TAG

Base Tag- Directly addresses a memory location. No special functions.

Alias Tag- Points to an addressed memory location defined by another tag. Some common uses for Alias Tags are associating Base tags with Module Defined Input and Output tags.

DATA TYPE

Data Type            Description        Bits        Possible Values

BOOL                     Boolean or Bit         1           0 or 1SINT                       Short Integer         8           -128 to 127INT                         Integer                   16           -32,768 to 32,767DINT                      Double Integer     32         -2,147,483,648 to 2,147,483,647REAL                      Real Number        32         +/-3.402823E38 to +/-1.1754944E-38

MORE DATA TYPE

Structure Data Type Type of Stored DataTimer Control structure for timer instructionscounter Control structure for counter instructionsControl Control structure for array instructionsMessage Control structure for the message instructionsPID Structure for the PID instructions