Share data cluster between two loops?

[Ola_A]

I realize it is friday afternoon, head not working so fast anymore.

I have a fairly big data cluster (100k data points altogether) that I use in the main loop, keep it in shift registers, adding/changeing data over time.

Now I like to read some of that data also in another loop, but did not find a good solution up front. It feels like it is a schoolbook example, and therefore I thought someone more clever than me might see a good solution directly!

[BowenM]

If you are running 2016, you might consider using channel wires.

[Ben · Accepted solution]

See here for a nugget I wrote on Action Engines.

If you are not familiar with them read that nugget and imagine moving your shift registers into a sub-VI that can be accessed from more than one loop.

It will cleanup your diagram a bit as well.

Ben

[aputman]

Functional global maybe? 

[Ola_A]

Sorry, I am at labview 2015, and need to compile at LV2012 in the end...

[crossrulz · Accepted solution]

With the assumption that you are only updating the value in one place and your other processes just need to read the latest value (do not care when it updates), I give you 2 options:

1. Data Value Reference (DVR)

2. Global Variable

If you are dealing with a large amount of data (I would put 100k data points in that category), I would go with a Data Value Reference (DVR).

[Ola_A]

Crossrulz, how would I code a Data Value Reference if I like to keep my shift register? The quick tests I just did suggested I need to make a new reference for each round in the main loop, and somehow transfer that reference to the other loop.

Ola

This vi does not work at all...

[crossrulz]

You need to create the DVR before both loops and pass the reference into the loops.

[Ola_A]

I understand the simple example, and is there a way to use a similar approach to read data that is stored in a large shift register?

[crossrulz]

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@Ola_A wrote:

I understand the simple example, and is there a way to use a similar approach to read data that is stored in a large shift register?

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Just make sure the data type of the DVR matches that of the shift register and it will work exactly the same way.