Data Acquisition (DAQ) and Control from Microstar Laboratories

Knowledge Base: Output

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Q10055 Benchmark on DAPcell server disk feed and output updates for DAP 5216a in DAPserver

Tags: Help, benchmark, DAPcell server, disk feed, output update, DAPserver

Applies to: DAPcell server, DAP 5216a, DAPserver

What is the maximum output update rate with DAPcell server feeding data to two DAP 5216a boards in a DAPserver?

With both DAP 5216a boards running, each DAP 5216a was updating outputs at the maximum aggregate rate of 2MS/s. The test configuration is described below.

Hardware setup

  • Two DAP 5216a/627 boards were installed with DAPcell Network Server v4.15 in a DAPserver522.
  • The DAPserver522 had a Pentium M 1.8GHz processor, a 250GB SATA 3Gb/s hard drive, 512MB DDR2 memory, and Windows XP SP2.

Software setup

  • The C++ example, DPDFEED, in the DAP Development software package was modified for a block size of 1048576 and to show the output count updated by the DAP.
  • The buffer size of the binary input communication pipe to the DAP board, $BININ, was increased from the default size of 4096 to 1048576 elements in the registry.
  • Two data files of over 4GB each were created, which allowed the test to run for almost 20 minutes.
  • A DAPL file was created to send data from $BININ to 32 digital output addresses using the TWOWRITE command. With 32 outputs and the two-write protocol used by TWOWRITE, the aggregate output rate of 2MS/s translates to 31.25 kS/s per output channel (2 MS/s / 32 / 2).
  • Two copies of DPDFEED ran in separate DOS command windows for the two DAP boards.