Error 74 occurred at Unflatten From String

[GerdW]

Hi Cristina,

- provide both VIs of sender and receiver

- provide example data of sent and received strings

- create and use a typedefined cluster for sender and receiver

[kevinks]

Hi, you might have already figured it out by now, but anyway, when you used TCP Read function, occasionally it would return an Error 56 because your TCP Write function in the specified IP address had not written anything or because the reading loop is executing faster than the writing loop (or so I think, don't kill me. I am a beginner 😄 ). 

The Type Cast function that you used however won't be aware of this Error 56 and would still try to convert the incoming string into the specified format. I am pretty sure that this can cause Error 74 as I have experienced the same. In order to solve the issue you can use a combination of shift register and case structure to filter out the Error 56 before you go to Type Cast it into a number.

[edmund99]

Hi i encountered the same problem and i am not sure where did it go wrong in my code.......

ClientServer

[altenbach]

Here are the most glaring errors, bu there are probably more.

Client:

• Your client is only sending the size because the flattened string is not wired to the second TCP write. (You fix that and the VIs will work just fine! :D)
• I don't understand the TCP read (and all that case structure stuff). Nothing is ever sending anything on that connection. Can you explain? (Also, "clear error" lets you specifically clear error 56, no need for that pyramid of case structures)

Server:

• The TCP read has a 1s timeout. I don't think you need the wait. The loop rate is determined by the sender.
• The typecast inside the case structure makes no sense. Typecasting a string to a string does nothing
• ...

General:

You should give all your cluster elements a descriptive label, then use bundle/unbundle by name. Much more self-documenting. You might even make the cluster a typedef.

Put all your controls/indicators in a cluster on the front panel. No need for bundling/unbundling. If you make the cluster container transparent, you would not even be able to tell the difference on the front panel.

...

[edmund99]

Thanks for the feedback alten,

to create the cluster i must do so by creating Reference of the various indicator/controls that i want in my cluster and use them to create clusters right? 

[altenbach]

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@edmund99 wrote:

to create the cluster i must do so by creating Reference of the various indicator/controls that i want in my cluster and use them to create clusters right? 

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Sorry, I have absolutely no idea what you are talking about. There is no need for references here. Can you add a few more sentences to explain what else is needed?

(Add the missing wire as instructed and you have a working VI. You can polish it up later.)

[edmund99]

Hi sorry what i meant was how do i create a type def cluster as suggested.

[GerdW]

Hi Edmund,

create the cluster with all needed elements, then store it as type definition...

Did you read the LabVIEW help on type definitions?