Data Acquisition (DAQ) and Control from Microstar Laboratories

Knowledge Base: Installation

Q10107 Using assigned DAP names in DAPcell software

Tags: Help, board names, DAP names, DAP order, UNC

Applies to: DAP, iDSC

We use two different system hardware configurations, and Windows reports different DAP numbering on these. It is too complicated for us to maintain separate versions of the software application to match what the hardware gives us, so the solution suggested in KB article Q10106 doesn't work for us. Is there an alternative?

Consider first the hardware-management approach presented in article Q10105. The reason that the DAP devices end up with different identification on different systems is that Windows detects its bus slots and ports in a different sequence on the two hardware systems. Perhaps you can solve the problem by swapping the physical locations of the DAP devices, using the approach described there.

But that approach sometimes isn't feasible because of physical constraints. There is another option: perform an "on-the-fly" substitution of device addresses in the DAPtools "client-side" software (the part that interacts with the application software and supports the DAPIO32 interface).

To use this option, your application programs must refer to DAP devices using artificial path names rather than actual UNC addresses, for example, something like the following.

      hDAP0_MessagesIn = DapHandleOpen("DAP0\\$SysOut", DAPOPEN_READ);

In the syntax of C++, the two backslash characters represent the value of one backslash character in the string. The address DAP0\$SysOut is a perfectly valid string, but not a normal UNC path. Under ordinary conditions, the function call would fail when DAPtools "client-side software" (the DAPIO32 programming interface) sends an invalid device address to the DAPtools "server-side" software (which controls devices). However, the "client-side" software first takes each device address and compares it to a local look-up table saved in the registry. If it finds an artificial path string matching the one that the application used, it substitutes the actual device address from the lookup table. Knowledge base article Q10087 describes how to configure the UNC mapping lookup table for the DAPtools software.

There are some potential hazards from using these "on-the-fly" adjustments. The DAPcell installation must be adjusted for each machine, and the configuration could be lost during various software upgrades. Another hazard is that any adjustments in the DAPcell configuration will apply to all applications that run on that system, so all DAP applications on the host system would need to use re-mapped device names consistently.


See topic Q10105 for information about making device names as consistent as possible.

See topic Q10087 for information about configuring the DAPcell device mapping table.

See the DAPIO32 Reference Manual for more information about function calls and UNC notations that establish connections to DAP devices.

See the Data Acquisition Processor control panel application manual for more information about DAP configuration.