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Creating Cams Programmatically

The BasicMotion_CreateCamTableOnline.project sample project is located in the installation directory of CODESYS under ..\CODESYS SoftMotion\Examples.

The example shows how you can use IEC code to create and use a cam. The following points are covered here:

  • A cam created in the cam editor is created again using IEC code.

    • In one case, the cam disk is generated in the bus task.

    • In the other case, the cam disk is generated in a separate task.

  • Then, all three cams are run with the same master axis and different slave axes. The movement of the three slaves is identical.

  • The cam generated in the IEC code is displayed in the visualization.

For more information about the programmatic creation of cams, see: Creating Cams Programmatically

Structure of the application

The application consists of the following components:

  • CamOffline

    The cam created in the cam editor which should be created again using IEC code.

  • PLC_PRG

    The program consists of a simple state machine and, logically, three parts. In the first and second parts, a cam is created in IEC code. In the third part, the previously created cams and an identical cam created offline are run.

    • Part 1:

      In the first state STATE_CREATE_ONLINE_TABLE, a cam is created in IEC code. The SMCB.CamBuilder function block from the SM3_CamBuilder library is used for this purpose. Three segments are added: a Poly5 element followed by a Line element and another Poly5 element. The Builder generates a CamOnline cam from this. From this point on, the cam is created in IEC code and can be used in the same way as the CamOffline cam created offline in the cam editor.

    • Part 2:

      In the STATE_INIT_ONLINE_TABLE_MULTITASK, STATE_START_CREATE_ONLINE_TABLE_MULTITASK, and STATE_READ_ONLINE_TABLE_MULTITASK states, the creation of the cam is started in another task and then it is read.

    • Part 3:

      In the STATE_POWER_DRIVES state, the virtual axes for the master and the three slave axes are initialized. The cams are then selected using MC_CamTableSelect in the STATE_SELECT_TABLE state and executed in the final STATE_MOVEMENT state. The master axis is moved using MC_MoveVelocity and is used as the master for the three cams.

  • MultitaskCamBuilder

    A program which generates a cam as described in Part 1 of PLC_PRG. The only difference here is that a multitask/multicore-safe variant of the cam is used.

  • GVL

    The multitask/multicore-safe variant of the cam is instantiated here.

  • Visualization

    The visualization contains the SMC_Visu_CamDisplayer element for displaying cams. The cam generated in Part 1 of PLC_PRG is displayed.

  • CamDisplayerSettings

    Additional elements for displaying the cam in Visualization

  • Trace

    You can use the trace to track the movement of the virtual axes. The current position of the master is recorded, as well as the position, velocity, and acceleration of the three slave axes.

Commissioning

  1. Build the application and download it to a controller.

  2. Start the trace and the application.

  3. Observe the sampling trace.

  4. Display of the generated cam in the visualization

In this section: