The latest versions of NI Modbus library can be installed through VI Package Manager as described here: LabVIEW Modbus API
Older versions of the Modbus library are in the Attachments section of this KB. The 3 files contain the following:
- Version 1.2.1 of the Modbus libraries.
- Compatible with LabVIEW 7.1 to 8.6.
- The recommended library for migration to later versions of LabVIEW.
- The read me file contains installation details.
- MSI installer.
- Compatible with LabVIEW 8.2.
- Modbus library version 1.1.
- Compatible with LabVIEW 7.1.
- Contains installer.
NI does not support older Modbus libraries. They are provided as-is, to allow developers to maintain existing LabVIEW applications. New applications should use the current version of the Modbus libraries.