Programmatically trigger a latch boolean?

[rajiv85]

Searched for previously solved solution but could not find a conclusive solution.

so I have a reset button set as a latch. I want a change value event to trigger this latch.

If there is no way to do it via a latch, in this case how to implement:

A value change event within my program ( non user triggered) which should trigger the latch which is found in another loop?

Many thanks for recommendations and help.

[GerdW]

Hi rajiv,

I have a reset button set as a latch. I want a change value event to trigger this latch.

Usually the button triggers the event case, not the other way around…

If there is no way to do it via a latch, in this case how to implement:

Simple solution: change from latch to switch…

[rajiv85]

So Gerd,

Does it mean that once the event is triggered, and I set the boolean to true as a switch then I need to use a sequence to set it back to false? Am just wondering if there is a better practice.

[GerdW · Accepted solution]

Hi rajiv,

Does it mean that once the event is triggered, and I set the boolean to true as a switch then I need to use a sequence to set it back to false?

For the simple solution: yes.

Am just wondering if there is a better practice.

Sure!

• Run your command only on value changes of your button (using BooleanCrossing).
• Use a QMH and send a command from your event loop to your loop containing the button…

[rajiv85]

Thank you very much!!

I already have a QMH in my program, so I will see how implement one for this. 

If I can please squeeze additional questions: I have one QMH, as an enum from my events box which trigggers a notification as shown:

1. So if I add a new notification ( based on an event) should I use a cluster or can I use multiple notifications? Further I see that for multiple notifications I have only ' wait on notification' .. while for a single notification I have 'get status' -> am wondering if the 'wait on notification' will stop my loop from running until it gets a notification ( in the case of multiple notifications 'bundled together' as an array--> build array. ?)

2. Just on this topic, am wondering why does mutiple notification does not have a get status, instead, wait on notification?

Big thanks for further clarifications.

[rajiv85]

Gerd, thank you so much again, the boolean crossing ( also very useful) led me to check the: ''Value Has Changed PtByPt VI'' which was actually what I needed. So I simply need to wire my dbl to this and it will trigger the boolean when there is a change. I was trying to implement this using a more complicated and long way 🙂

 

[GerdW]

Hi rajiv,

So if I add a new notification ( based on an event) should I use a cluster or can I use multiple notifications?

When you need a different notification you need to use a different notification!

(I don't get the question on "use a cluster"…)

am wondering if the 'wait on notification' will stop my loop from running until it gets a notification

There is a timeout input…

Just on this topic, am wondering why does mutiple notification does not have a get status, instead, wait on notification?

Ask the NI support as they should know…

Why do you even compare the "Wait for…" functions with the "notifier status" function? There is a WaitForNotification and WaitForMultipleNotification…

the boolean crossing ( also very useful) led me to check the: ''Value Has Changed PtByPt VI'' which was actually what I needed.

Then why didn't you ask for that in the first message?

[rajiv85]

So: the notifier status, am using it to communicate with different SubVis. I did not test it yet, but am assuming that wait on notification will cause a waiting for a notification to arrive for it to run the SubVI. That subVI needs to run all the time. So I wondered why we dont have 'notifier status' for the multiple notifiers.

[GerdW]

Hi rajiv,

but am assuming that wait on notification will cause a waiting for a notification to arrive for it to run the SubVI. That subVI needs to run all the time.

But you don't need to read the notifier each microsecond!

Set a reasonable timeout value…

So I wondered why we dont have 'notifier status' for the multiple notifiers.

Because you don't need it…

[GerdW]

but am assuming that wait on notification will cause a waiting for a notification to arrive for it to run the SubVI. That subVI needs to run all the time.

But you don't need to read the notifier each microsecond!

Set a reasonable timeout value…

So I wondered why we dont have 'notifier status' for the multiple notifiers.

Because you don't need it…

[rajiv85]

Thank you Gerd!

-I will include a time out!!!

-Am not quite understanding why we would not need it for the case of multiple notifiers. But this is surely a lack of knowledge from my side. I will need to find out what is the difference between: notifier status and wait on notification.