error 200524 with Simultaneous analog output multiple channels

[ange_gardien]

Hi 

when i try to runmy vi i got the error 200524. can you please help me? what can i do to change the graph"courbe intensité-Tension" with an xy graph with multiple plots.

thanks

[cbutcher]

The error code you report relates to a different number of inputs to the Write function than the number expected. I'm not entirely sure why this is with the code that you sent. Is it exactly the same as the code you tested? In particular, you did it with the Simulate Signal wired to the False case of the Select node?

The DAQ Assistant in the top right corner of the loop appears to be the only place where a write occurs. The dynamic data type that you're wiring to the select function has more that one value (it contains a waveform consisting of multiple values) but the coercion at the Select node is (at least for me) taking only the last value (-0.04).

If you switch the two options (such that the Simulate Signal goes to True, and the "Pas de variation de V_RE Voltage" is the false case, then you output a dynamic data wire, which will trigger this error. The DAQ Assistant is configured with only one channel as I can see it - is this also true in the code you tested?

Regarding your second problem, I wasn't able to see a graph labelled "courbe intensite-Tension" (sorry, don't remember the key-code for acute) but I always find the Detailed Help (available via Context Help) to be of great assistance when plotting XY Graphs with multiple plots (and sometimes even for single plots!).

You can open context help by pressing Ctrl-H and then the Detailed Help is linked at the bottom when you hover over the XY Graph terminal. Scrolling down a tiny bit will get you the following text:

Displaying Multiple Plots on XY Graphs
The XY graph accepts three data types for displaying multiple plots. The XY graph accepts an array of plots, where a plot is a cluster that contains an x array and a y array.

The XY graph also accepts an array of clusters of plots, where a plot is an array of points. A point is a cluster that contains an x value and a y value. The XY graph also accepts an array of clusters of plots, where a plot is an array of complex data, in which the real part is plotted on the x-axis and the imaginary part is plotted on the y-axis.

which is to say, there are three ways to place multiple plots on an XY Graph. The way that I expect you'll want to use is the one I highlighted in bold. You bundle your X and Y values into a cluster, then use Build Array to add that point each iteration. You then bundle these 1D arrays of clusters, and then use Build Array on the (new) cluster, such that when hovering over the output wire it reads (in Context Help) as follows:

Here the names of the data elements are "number: 0 to 1" because I used the random number input, but yours will be different.

[ange_gardien]

thanks for your help

for the DAQ assistant i use 2 analog ouputs not one. i tried to switch beteween dynamic data (signal) and "pas de variation" but i still have the same error. for the xy graph, can you please give me an exemple how to do it because i am a neophyte regarding the use of LabVEW. please excuse my ignorance

thanks

[cbutcher · Accepted solution]

It seems to me that your goal with the output is to switch between a constant value (controlled by the front panel control) and a simulated shape (like triangle). You should set the number of outputs to 1 (since you only have 1 output channel) and use the switch like you have, but you either need to set the Simulate Signal to only output 1 value (which might give you a poor quality output) or set the DAQ Assistant responsible for Writing to use an array of N points 1 Channel, and then use Initialize Array with the appropriate constant value (N_Samples) to create your constant like so:

This is only a screenshot, but shows Simulate Signal configured to output 100 points, and the constant value being converted to an array of 100 values (all with the same value). This can then be wired to the input of the DAQ Assistant, if the assistant is reconfigured to write multiple points at once.

Which inputs did you want to graph for the XY-Graph?

[ange_gardien]

please take a look to the screenshot i"ve sent. i would like to change the Graph"courbe intensité-tension" to XY Graph.

thanks

[cbutcher · Accepted solution]

Right, so to be clear, you have 4 DBL inputs, which form two X-Y pairs, and you want to add a new pair to each plot once per iteration, and you want to update the graph each iteration with both plots?

If so, you can do this:

Here you see me bundle the X and Y values, then I place them in an array using Build Array. This step is used to allow the For loop to auto-index, preventing the need to use something like Index Array. For only two cases, you could do this without the For loop, but it would probably take more room on the block diagram. If your number of plots increases, it's definitely worth trying to keep it in one place.

Then, inside the For loop, I unbundle the auto-indexed incoming array of clusters. This leaves me with the content of the cluster - the array of points. I append to this array, using the Concatenate Inputs option for the Build Array node. After that, I use Bundle to put it back inside a cluster (of 1D array of clusters of 2 DBL values) and then pass it out of the For loop, using auto-indexing again to create an Array of Clusters of Array of Clusters of 2*DBL, which I can wire to the XY-Graph.

[ange_gardien]

thanks for your help. you save my day.

thanks