Data Acquisition (DAQ) and Control from Microstar Laboratories

Knowledge Base: Processing

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Q10041 Previewing custom processing without DAP board

Tags: Help, DAP, DAPL, custom module, processing, preview, emulation

Applies to: Custom command modules, host system software

I noticed that when I compile custom command modules, the compiler generates a DLM file type that is in essence a DLL file. Is it possible to run this DLL file on my PC and study its custom commands without involving a DAP board?

Unfortunately, no. The reason is that the file contains code intended for the DAPL system. The DAPL system operates in a fundamentally different way than the host operating system, and only runs on a Data Acquisition Processor.

Using the DLL file format for downloadable module DLM files is mostly a matter of convenience. The DAPL system needs to load binary modules developed by users, and in the process of the download, it needs to access an export list of functions provided by the module. There are many ways of doing this, but the DLL way works fine. It has the very big advantage that the compiler (or more specifically, the linker) can be coaxed into generating the file directly. No special utilities are required to generate code modules that work with the DAPL system.

A file format is just a way of presenting data. A DLL/DLM file is laid out in a certain way. Names are in their proper place, addresses are in their proper place, and binary elements are in their proper place. In a DLM downloadable module, the code elements represent DAPL tasks, DAPL system callback functions, and so forth – not Windows application functions. Code that runs on a DAPL system has no relationship (other than sharing a common processor family) with the code that runs on a PC host operating system.

It is conceivable that a software package in the host system could read the DLM file, emulate the functions of the DAPL system, and run the processing commands within the host system environment. The difficulty of doing this has, so far, discouraged anybody from attempting it.