Memory board vis, Memrdprt.vi – Measurement Computing UL for NI LabVIEW User Manual
Page 89
Universal Library Virtual Instruments (VIs)
Memory board VIs
Memory board VIs
MemRdPrt.VI
Reads pre-trigger data from a memory board that has been collected with either APretrBg.VI or APretrFg.VI
and arranges the data in the correct order (pre-trigger data first, then post-trigger data). This VI can only be
used to retrieve data that has been collected by either APretrBg.VI or APretrFg.VI with the ExtMemory
option set to TRUE. After each APretrFg.VI or APretrBg.VI call, all data must be unloaded from the memory
board with this VI. If any more data is sent to the memory board then the pre-trigger data will be lost.
Summary:
Inputs:
BoardNum
[U32] - The board number assigned when installed with InstaCal. Can
be 0 to 100.
FirstPoint
[I32] - Index of first point to read or
FROMHERE
.
Count
[U32] - Number of points (words) to read.
Outputs:
DataArray
[U16] - Output data array.
ErrCode
[I32] - Error code. See ErrMsg.VI.
Arguments:
BoardNum
The board number associated with a board when it was installed with InstaCal.
FirstPoint
Use
the
FirstPoint
argument to specify the first point to be read. For example, to
read points #200 - #250, set
FirstPoint
=200 and
Count
=50.
If you are going to read a large amount of data from the board in small chunks then
set
FirstPoint
to
FROMHERE
(-1) to read each successive chunk. Using
FROMHERE
(-1) speeds up the operation of MemRdPrt.VI when working with
large amounts of data.
Count
Number of points (words) to read.
DataArray
Data read from memory board.
ErrCode
Error code returned from the Universal Library. Zero if no error occurred. Use the
ErrMsg VI to convert
ErrCode
into a readable string.
Notes:
DT Connect conflicts - The .MemRdPrt.VI can not be called while a DT Connect transfer is in progress. For
example, if you start collecting A/D data to the memory board in the background (by calling AInScBg.VI or
AInScFg.VI with the
DTCONNECT
+
BACKGROUND
options), you can not call MemRdPrt.VI until the AInScBg.VI
or AInScFg.VI has completed. If you do, you will get a
DTACTIVE
error.
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