feedback nodes for sequences in LV8.2.1 ?

[BenoitProvost]

Hi,

  I used feedback nodes with stacked sequences several times in the recent past, but lately it does not seem to work anymore...  I reinstalled some LV components lately, and I am wondering if I unintentionaly downgraded parts of LabView. Are automatic feedback nodes in squences included in LV8.2.1?

  Basically I need to transfer data from sequence 0 to sequence 1 in a stacked sequence. I used to simply wire it and a feedback node would appear automatically. Now it just gives me a broken wire and complaints about creating a cycle. I tried adding the feedback node manually, but it does not accept it. The "Help" explain methods exactly like I would expect it, but it just does not work...

  Also, my older VIs with feedback nodes still compile correctly (no errors).

  Any idea what may be going on?  I guess I can use a flat sequence, but I was really planning to use a stacked sequence to keep the block diagram small and uncluttered.

  Thanks,

  Benoit

[HaD]

Please attach a simple vi that demonstrate the error.

[Dennis_Knutson · Accepted solution]

You use Sequence Locals to pass data from one frame to another. I don't understand how you could be using a feedback node. Need your VI or an image.

p.s. Sequence structures of any type are seldom required and the use of a stacked sequence is considered by many to be very poor style. You should consider how to remove the sequence structure all together and use dataflow.

Message Edited by Dennis Knutson on 03-10-2009 01:33 PM

[BenoitProvost]

I don't know why I did not see this "Add Sequence Local" menu item before...  It works well.  Thanks!

For some reason LabView used to insert feedback nodes before and it also worked. I will start using sequence locals from now on.

Benoit

[Dennis_Knutson]

Even better would be stop using sequence structures.

[BenoitProvost]

The reason I was using a sequence was that I needed a delay between steps (using the simple "wait" VI). However, now I am using the "Time Delay" VI instead, which has Error In and Error Out terminals. This provides delay dependency from previous and following steps, and therefore I don't need a sequence anymore.

Thanks,

Benoit