How do I AI config for SCXI multiple non-contiguous channels 
Author Message
 How do I AI config for SCXI multiple non-contiguous channels

I need to configure a measurement of with multiple groups of
thermocouple channels.
Using LV 5.1.1 (could use 6, but I am supporting lots of code built
with 5.1.1), DAQ 6.8.1 (can up to 6.9.1 if it matters), PXI-6052E,
SCXI-1102, SCXI-1303 (or TC-2095).(using SCXI addressing).

The problem occurs when I try to configure multiple scan lists with
gaps between channels.
(see LV DAQ SCXI example SCXI-1102/1127/1101 Thermocouple)
example channel list:
ob1 ! sc1 ! md1 ! cjtemp
ob1 ! sc1 ! md1 ! 0:3
ob1 ! sc1 ! md1 ! 5:9
This gives an error: -10370 in AI Group Config.
Likewise if I use an individual channel in each address string.  like:
..md1 ! 0
..md1 ! 1
..md1 ! 3

But, I can skip channels between cjtemp and the first channel of the
next scanlist without error.
Also, I can add scan lists for other modules, like:
..md1 ! 0:3
..md1 ! 4:8
..md3 ! 12:14
without error!

What I really want to do is to do AI Config first for all channels,
then start, then loop on AI Read and some processing & storage.
When I loop through the channel address lists (strings with contiguous
channel sets e.g. 3:6) I get the same task # for all config calls.
Then when I loop through the AI Start's for each , I get an error
-10609 in AI Clock Config.

  The thing is that I cannot necessarily have all contiguous channels,
and I don't want to go through a sequence of {AIConfig, AIStart,
AIRead, AI CLear} for each scanlist each time through.  That takes too
much time and resources.

 Eventually I want to configure multiple non-contiguous scanlists in
multiple SCXI modules.
But, for right now I need to do this for one SCXI module.

Anyone have any ideas?
How can I approach this.
Thanks
Dave



Thu, 19 Aug 2004 06:17:49 GMT  
 How do I AI config for SCXI multiple non-contiguous channels
Dave
Check the following link into the NI Knowledgebase (if you haven't already)
which I think explains your situation.

http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/02a...
e8bd15862567e700577877?OpenDocument

Bottom line is you will not be able to skip channels on any SCXI module
other than the SCXI-1112. You will need to include the channels in your scan
list then discard the data later.

Either that or as the Knowledgebase suggests, use Virtual Channels. You can
then miss channels out in the scan list as you require. They actually get
scanned but NI-DAQ discards the data for you.

Ian Bell
NI UK


Quote:
> I need to configure a measurement of with multiple groups of
> thermocouple channels.
> Using LV 5.1.1 (could use 6, but I am supporting lots of code built
> with 5.1.1), DAQ 6.8.1 (can up to 6.9.1 if it matters), PXI-6052E,
> SCXI-1102, SCXI-1303 (or TC-2095).(using SCXI addressing).

> The problem occurs when I try to configure multiple scan lists with
> gaps between channels.
> (see LV DAQ SCXI example SCXI-1102/1127/1101 Thermocouple)
> example channel list:
> ob1 ! sc1 ! md1 ! cjtemp
> ob1 ! sc1 ! md1 ! 0:3
> ob1 ! sc1 ! md1 ! 5:9
> This gives an error: -10370 in AI Group Config.
> Likewise if I use an individual channel in each address string.  like:
> ..md1 ! 0
> ..md1 ! 1
> ..md1 ! 3

> But, I can skip channels between cjtemp and the first channel of the
> next scanlist without error.
> Also, I can add scan lists for other modules, like:
> ..md1 ! 0:3
> ..md1 ! 4:8
> ..md3 ! 12:14
> without error!

> What I really want to do is to do AI Config first for all channels,
> then start, then loop on AI Read and some processing & storage.
> When I loop through the channel address lists (strings with contiguous
> channel sets e.g. 3:6) I get the same task # for all config calls.
> Then when I loop through the AI Start's for each , I get an error
> -10609 in AI Clock Config.

>   The thing is that I cannot necessarily have all contiguous channels,
> and I don't want to go through a sequence of {AIConfig, AIStart,
> AIRead, AI CLear} for each scanlist each time through.  That takes too
> much time and resources.

>  Eventually I want to configure multiple non-contiguous scanlists in
> multiple SCXI modules.
> But, for right now I need to do this for one SCXI module.

> Anyone have any ideas?
> How can I approach this.
> Thanks
> Dave



Thu, 19 Aug 2004 07:24:58 GMT  
 
 [ 2 post ] 

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