Has anyone else ever had a problem where you had to perform 2 datasocket writes before the datasocket read would pick up the change?

Question

I have a local VI that is simply a control that writes to the datasocket server whenever the control value changes.(the dataitem on the server is permanent - its initialized and never released by the server)
In the same local VI I have a datasocket read polling a different dataitem on the server.
The remote machine has a VI that reads the permanent dataitem on the server once per second.
For some reason, after adding the local VI mentioned above, the remote VI stopped picking up the first change in the permanent variable.
I'd start both the local and remote VIs...
Then change the local control and the remote V
I would not update - as if the datasocket write(upon adjusting the control) did not take place. So I'd change the control value again - this time the remote VI would update to this new value. And from here on out - the remote VI would update correctly. This problem only occurs when the local VI is first started up.
What in the heck is going on?

Answer 1

dingler44 wrote:
>
> Has anyone else ever had a problem where you had to perform 2
> datasocket writes before the datasocket read would pick up the change?
>
> I have a local VI that is simply a control that writes to the
> datasocket server whenever the control value changes.(the dataitem on
> the server is permanent - its initialized and never released by the
> server)
> In the same local VI I have a datasocket read polling a different
> dataitem on the server.
> The remote machine has a VI that reads the permanent dataitem on the
> server once per second.
> For some reason, after adding the local VI mentioned above, the
> remote VI stopped picking up the first change in the permanent
> variable.
> I'd start both the local and remote VIs...
> Then change the local control and the remote VI would not update -
> as if the datasocket write(upon adjusting the control) did not take
> place. So I'd change the control value again - this time the remote
> VI would update to this new value. And from here on out - the remote
> VI would update correctly. This problem only occurs when the local VI
> is first started up.
>
> What in the heck is going on?
Gorka is right, this came up on Info-LV a few days ago. Someone
described a similar problem. I replied that I had seen similar
behaviour, reported it to NI, and they verified a bug. There is no fix
yet, but they are aware of it and will fix it. No anticipated release
date for the fix.
Regards,
Dave Thomson
David Thomson 303-499-1973 (voice and fax)
Original Code Consulting [email protected]
www.originalcode.com
National Instruments Alliance Program Member
Research Scientist 303-497-3470 (voice)
NOAA Aeronomy Laboratory 303-497-5373 (fax)
Boulder, Colorado [email protected]