The Delacor Queued Message Handler (DQMH) template is based on the National Instruments Queued Message Handler Project Template (NI QMH). The DQMH improves the NI QMH by:

  • providing safe, event-based message handling and scripting tools, which makes development easier
  • encouraging consistent style among different developers in the same project, which improves efficiency

The DQMH provides the greatest benefits in applications employing multiple modules running in parallel that communicate with each other. These different modules can run either with their front panel open or headless (with their front panel closed). The DQMH can also be used for applications that have a single module in which a Tester has the capability of eavesdropping on the different DQMH events and messages (both in development mode and in an executable).

Each DQMH module has a structure similar to a National Instruments Queued Message Handler module, and it has a Test DQMH Module API.vi (also known as the "Tester") to help troubleshoot, debug, and eavesdrop on the communications between the DQMH Module and its calling code. If the developer is creating an application that will employ multiple DQMH modules, the best place to start is with the Project Templates. This is done by clicking Create Project from the Getting Started Window in LabVIEW, and then clicking the DQMH Project Template. If the developer is creating a single DQMH module that will be called by their existing code or used as a stand-alone application, open an existing project and use the Tools>Delacor>Module>Add DQMH Module utility. Starting with DQMH 4.1, there is also a Sample Project Template for the DQMH version of the Continuous Measurement and Logging (DQMH CML) Sample project. Create a copy of this sample project by clicking Create Project from the Getting Started Window in LabVIEW, and then clicking the DQMH CML Sample Project Template.

This documentation assumes that you are familiar with Producer/Consumer design pattern and with the NI QMH Project Template. If you are not familiar with these topics, the NI QMH documentation can be found by clicking Create Project from the Getting Started Window in LabVIEW and then clicking the More Information link in the NI QMH project description. You can also create a project based on this template, which will include a copy of the documentation.