Q10104 Communication pipe failure after upgrading DAPtools software
After upgrading from DAPtools version 4.3 to DAPtools version 5.1, my application fails to start correctly. I discovered that the DAPL system runs out of memory before it finishes setting up the communication pipes. Do I need to do something different for setting up communication pipes?
Buffer memory is reserved for a communication pipe created
by an application using the DLL function DapComPipeCreate
,
or using the Data Acquisition Processor application in the Control Panel.
The default settings of DAPcell 6.x services, from DAPtools package 5.xx,
attempt to optimize performance of Windows Vista, Windows 7, and Windows 8
systems by reserving 8M storage elements. Sometimes this demands too much
buffer memory, particularly for DAP board models having less than 128MB of
physical memory. To correct this problem, use the maxsize
option
to establish a smaller buffer memory size on the DAP side of the commmunication
pipe. Shown below are some examples of how to apply this adjustment. The examples
assume communication pipes of type long
because the 32-bit elements
are more likely to cause problems, but the same solutions apply for pipes
transferring other data types (byte
, word
,
float
, double
, text
).
\\<server>\<dap>\Cp2Out [maxsize=4096 type=long]
- both PC side and DAP side have 4096 buffered elements
\\<server>\<dap>\Cp2Out [type=long | maxsize=4096]
- the DAP-side buffering is limited to 4096 elements, while the PC side uses the default 8M elements
The DAPcell software on the DAPtools 6.00 release and later uses
different rules for setting communication pipe default sizes on the DAP
side, based on the buffer memory available on the DAP board, so ordinarily
you should not need to make these same adjustments. Boards with 128MB or
more of buffer memory will continue to use the large communications
buffers for maximum compatibility with Windows 7 and Windows 8. If your
application uses several communications pipes, it remains possible to
run short of buffer memory, and you might need similar reductions in the
maxsize
properties of your communication pipes.
L24463
More information about properties of communication pipes is available in the DAPIO32 Reference Manual