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Member
wideofthemark
Posts: 95
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labview class data read node problems

I've been noticing some odd things when i use read\write nodes on labview class objects. 

 

It seems like at some point the link between the read node and what it's supposed to be doing gets broken - so that it reads out the 'default' value of the data than the actually written value.  I have worked out how to fix it when it happens - by deselecting the correct node, and then reseleecting it - seems to refresh whatever is happening underneath - although it is a pretty annoying bug.

 

It seems to have started happening in the last few months when i updated to LV2011 SP1 in code that had been unchanged for at least a year. (so LV2010).

 

I can't quite pin down the exact circumstances because it seems a bit transitory.  It seems to mostly happen after labview crashes - which seems to happen quite often in LV2011.  I have a feeling it might be especially when you do class inheritance.

 

Anybody else noticed this behaviour?  Have been wondering if I should avoid using these node read\writes, and go for the actual VIs.

 

JP

Member
Aaron_E
Posts: 107
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Re: labview class data read node problems

Hi JP,

 

Many thanks for your post. I have been using LabVIEW 2011 for a recent OOP project and not experience this behaviour so believe it could be an issue introduced in SP.1.

 

I have checked and this is not a known issue with LabVIEW 2011 SP.1. I have had a go at recreating the issue in SP.1 but have been unable. In order for me to report this as a known issue and ensure it gets rectified I need to be able to recreate the behaviour. If you are able to explain some steps to recreate the issue then this would be great. Alternatively, could you send me in a VI/project which has the issue?

 

If it seems to occur after a crash then I suspect the two are related and the key will be identifying what is causing LabVIEW to crash.

 

Best Regards.

Aaron. E
Applications Engineer Team Lead
National Instruments
ni.com/support
Member
wideofthemark
Posts: 95
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Re: labview class data read node problems

Thanks for the reply.

 

I can dig out the code that seems to show it.  However as i tried to say it seems to be an intermittent fault - in the sense that I generally see it after something else has gone wrong - ie after a recovery from a hard Labview crash.  I guess it may be a problem with the labview 'recovery' bit rather than other stuff.

 

JP

 

Member
Aaron_E
Posts: 107
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Re: labview class data read node problems

Hi,

 

If you could upload the code after the issue has happend and before you have fixed it then it will be interesting to see the effects.

 

Many thanks,

Aaron. E
Applications Engineer Team Lead
National Instruments
ni.com/support