How to use a Switch connected to DAQ Card as event source in an Event Structure

[Shining_Eagle]

Is easy use a Front Panel Switch as event source. However, I want to do use an external switch hardwire to my DAQ Card (NI PCI-6229) as the event source in the Event Structure. Can anyone help?

[stevem181]

You can use "User Events" to generate events whenever/wherever you want. User Events use dynamically registration.

See the example program: Programmatically Fire Events.vi (yes it does have 2 "m"s in LV2009)

Notes:

• To get started, right-click the event structure border and select "Show Dynamic Event Terminals".
• The Events palette is hard to get to quickly, so I just right-click on an event item (like the Dynamic Event Terminals) to bring up the palette
• You can generate the same event from multiple places
• If you have more than one User Event, bundle the "Create User Events" outputs and use naming to "self document" code
• You can replace "value signaling" calls with User Events
• User Events are quite powerful and deserve more attention than they get

steve

[Hueter]

Here is some more usful info on User Events

LabVIEW 2009 Help : User Events 

[Shining_Eagle]

Happy New Year!!!

Thank you. I put all the field wired inputs from the DAQ Card into a Cluster. I use unbundle by name to call the switch, the state changes on the probe but I am having no success in activating an event using the "value change" from any Push Button.  Even if I put an indicator to double check the event is happening, I don't see indicator light turning on. Will you be able to show with an example vi?

================================================================== 

You can use "User Events" to generate events whenever/wherever you want. User Events use dynamically registra I ion.

See the example program: Programmatically Fire Events.vi (yes it does have 2 "m"s in LV2009)

Notes:

• To get started, right-click the event structure border and select "Show Dynamic Event Terminals".
• The Events palette is hard to get to quickly, so I just right-click on an event item (like the Dynamic Event Terminals) to bring up the palette
• You can generate the same event from multiple places
• If you have more than one User Event, bundle the "Create User Events" outputs and use naming to "self document" code
• You can replace "value signaling" calls with User Events
• User Events are quite powerful and deserve more attention than they get

[stevem181 · Accepted solution]

Happy New year to you too!

Attached is an example in LV 8.5

• It uses the timeout loop (running every 100ms) to simulate your reads from the DAQ card.
• A shift register is used to keep track of the previous value of the switch.
• When a switch change is detected, the User Event is fired and the indicator shows the new state.

Running the vi with highlight execution turned on may be helpful.

steve

[Shining_Eagle]

Thank you so much Steve!!!

I will continue playing with Event Structures.