Rif.: graph multi courbes XY

[juliedtr]

Bonjour, 

J'ai plusieurs problèmes avec mon graph multicourbes xy (problèmes que j'avais aussi avec un graph déroulant), pourriez vous m'aider ?

En effet je n'arrive pas :

-à relier les axes avec les variables correspondantes (le time, soit l'abscisse du graph, ne correspond pas à ma variable temps que j'ai défini et qui diffère du temps introduit par le graph)

- ni à faire correspondre les courbes avec ce qui leur correspond (par exemple la courbe de température prend les valeurs de débit) 

- 2 autres courbes ne s'affichent pas (alors qu'elles sont sélectionnées, les couples câblés et ayant des valeurs)

Je vous joins des screens (car le VI nécessite des DLL et des sous VI) 

[pincpanter]

Vous avez oublié les images...

Posting your vi, even broken, can be useful anyway. Pictures often hide important details.

[juliedtr]

Ah ça n'avait pas marché...

Les voici et je mets le vi aussi

  

[pincpanter]

You need to wire an array of times and an array of corresponding values to each cluster.

If you want to wire scalars, you need to go back to the strip chart.

Also remark that you don't need to create a variable for each wiring: it's ok to directly wire to all clusters the value coming from the division (by 3600).

Similarly, the array of times is certainly the same for the temperature and for the rate (débit), since they are acquired simultaneously.

Sorry, my technical French is not good enough.

[juliedtr]

I tried to do what you told me but I'm not sure to have understand clearly what you meant ...

Could you make me a little VI for exemple or modify mine please ? 

Julie 🙂

[pincpanter · Accepted solution]

Ciao Julie,

I attached a modified version of your vi. Although I can't test it, it should display properly the temperature and the rate.

The other two quantities - CO2 and fermentation - could be added too but they need a different array of timestamps, since their value is only produced when you SAVE.

Unfortunately the graph is not the only problem in this vi. You should really try to understand the dataflow paradigm. Using a local variable every time you need to use a given value is wrong and can lead to unexpected results. See for example the SAVE case: you are at the same time calculating and saving CO2 cumulé, but since there is no sequentiality enforcement, you don't know if you are saving the previous or the newly calculated value. LabVIEW will pick one of the two values, but it may not be the same you would choose.

Instead, wire values directly as much as possible. Check the SAVE case for a partial example of what I mean.

Also remark, for example, that I dropped all variables for temps (h): they are definitely not needed, since for each iteration there is only one value for the time.

[juliedtr]

Thx a lot !!!

Julie