Tag engine dynamic events

[unclebump]

Does anyone have an example using dynamic events with tag values from the DSC engine?? I use 7.0 format.

[Arun_V]

Hello,

We do not have an example available at this time. But I feel compelled to point you out to some developer zone examples and documents that talk about dynamic events. I am sure you would have gone through these documents but still wanted to make sure.

http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=BDB5933673582153E034080020E74861&p_node=DZ52054&p_source=External

http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=B45EACE3F01D56A4E034080020E74861&p_node=DZ52036&p_source=External

http://zone.ni.com/devzone/conceptd.nsf/webmain/aa79ff38336eb38886256d2b004aca49#3

If you have already gone thro' these links, I apologize for being redundant. Also, I was wondering the background in you choosing to go with dynamic events for tag values.

Regards,

Arun V
National Instruments

[unclebump]

I wanted to make a state machine with the event structure based on tag value changes. I was hoping to avoid reading tags and/or the value signaling property. I also tried the HMI wizard on a boolean indicator, but this doesn't seem to activate the value changed event structure.

[chrisger]

hi there

the "Tag Name to DataSocket URL" - VI translates a Tag name to a Logos - URL like "logos://localhost/LabVIEW/Analog Tag". Try to read the URL with DataSocket read function and set a Val.Signaling property when no timeout has occured.

best regards
chris

[unclebump]

This is what I came up with using the value signaling property. I made a new boolean crossing vi that works with an array input and output. This let me monitor multiple tags with one tag read.

[tomker]

Too bad that the example does use polling for tag values. I hoped that there  is a way to create an dynamic event when a tag value actuelly has changed.
A "changed" boolean output does exist in the read tag vi - why can´t I couple this with an dynamic event?
This sort of function really would ease my programming
thanks for any help
tom

[chrisger]

hi there

you can combine DataSocket Read - function with timeout and a registered user event (see attachment)

[chrisger]

oh, yeah, and the 7.0 version....

[tomker]

Thanks chris - I tested your 7.1 vi. It does the job!!!
I tried to pack the top part - "create user event -- until --> destroy user event" into a subvi to get a smaller code,
cause I´ll do this for some Tags. This didn´t work.
tom

[chrisger]

hi there,

well, take a look at this.. (see attachment..)

be sure to read the comments on the block diagrams.