Accessing actual min/max values and number of samples for ASYNC channels

Hi,

I'm using the DWDataReader DLL v4.2.0.2. I can access all data, but it seems when asking for the number of samples of an ASYNC channel, the function DWGetScaledSamplesCount(int ch_index) seems to scan through the whole file and counts all samples. That takes quite some time for big files (2-4 GB).

When looking at the hex dump of the DXD files I saw that there is a XML part at the end that contains those values, together with the actual min/max values of each channel:

<StoredChannels>
<Channel Index="AI;0">
<AbsMin>5.87185859680176</AbsMin>
<AbsMax>5.94458246231079</AbsMax>
<AsyncSamples>0</AsyncSamples>
</Channel>
<Channel Index="AI;3">
<AbsMin>-0.423298865556717</AbsMin>
<AbsMax>1.50738143920898</AbsMax>
<AsyncSamples>0</AsyncSamples> </Channel>
...
<Channel Index="GPS;0;X">
<AbsMax>545.50432</AbsMax>
<AsyncSamples>10</AsyncSamples>
<AbsMin>545.50401</AbsMin>
</Channel>
<Channel Index="GPS;0;Y">
<AbsMax>2933.01929</AbsMax>
<AsyncSamples>10</AsyncSamples>
<AbsMin>2933.01919</AbsMin>
</Channel>

Is there any way of getting this information AbsMin, AbsMax, AsyncSamples through the DLL functions? I tried DWGetChannelProps with DW_CH_XML, but it seems to not be in there.

Thanks in advance
Holger

Hi,

there unfortunately isn't any way of accessing these parameters with DWDataReader's functions. The only way that you can get them is to parse them out of he XML, which you've already discovered.