Modifying the Model File - Metasys - LIT-12011829 - Field Device - VMA18 VAV Modular Assembly

N2 VMA Application Note

Product name
VMA18 VAV Modular Assembly
Document type
Application Note
Document number
Revision date

This section describes the changes required to the VMA14xx model file for the VMA1832 controller.

To modify the model file:

  1. Using a text editor, open the model.und file you created and save it as a new file named model.dll.
  2. In model.dll file, locate the VMA14xx controller.
  3. Locate the VMA14xx CS models intended for use as VMA1832 models. Copy the entire model definition and paste it above the old definition.
  4. In the pasted copy of the model, change the model name of the copied model.
  5. Change the Hardware Type in the CSMODEL line from "VMA" to "VND" (Figure 1).
    Note: The DDL compiles does not allow spaces in point references or the model name.
  6. Open the PRN file created by CCT for the new controller application. Review the point list and attributes of the copied CS model and compare its point list with the PRN file of the VMA1832 controller, using Figure 1 as an example. Most of the points in your copied model should match points in the PRN file.
    Figure 1. PRN File Parameters and Model File Modifications

    Table 1. PRN and Model File Callout Numbers and Descriptions




    Model Name


    Hardware Type


    Point Reference


    Short Name

  7. Delete any points from the new model file that are not supported and do not appear in the PRN file. If possible, keep the CS attributes the same for any points that are referenced and make sure the points are in the same order.
  8. Review each short name in the new model and locate the corresponding short name in the PRN file. See Figure 1 for examples. Verify the PRN point reference information with the model point reference. If necessary, change the model to match the PRN file. In Figure 1, the AI2 point reference with the WC-ADJ short name in the model file must be updated to match the ADF2 point reference with the WC-ADJ short name in the PRN file.
  9. Review the PRN file for new points to include in the model file and add them in the appropriate model section.
  10. Save the updated model file to the FMSDATA path.