Is this graphical representation possible?

[mikel_jo]

Hello,

I started looking into Diadem to see if it fits to my needs, and I'd like to ask here if it is possible to use it for creating a specific graphical representation.

For example, I'd like to have the charactersitic of a bipolar transistor, as shown here: https://en.wikipedia.org/wiki/File:Current-Voltage_relationship_of_BJT.png (only the black traces). There is an output parameter (the collector current) that is measured by sweeping two input parameters (the base-emitter voltage and the collector-emitter voltage).

Or, in a more general case, there is an output parameter Out, that depends on several input parameters In_1, In_2, In_3, etc. I'd like to have an XY chart with Out on the Y axis, In_3 on the X axis and several traces for all values of In_1, while In_2 and all others have some fixed values.

Is something like this possible, preferably without scripting? Should the data be structured in a certain way in order to achieve this?

[Jupiter02]

 Hi mikel_jo,

From my understanding of your post, it sounds like you'll want each curve to be a different channel in a group. If you want In_3 to be your X-Channel, you can place this channel first in the group. If you drag and drop this group from the Data Portal to a 2D Axis System on the REPORT tab, this will plot your remaining curves as Y-Channels with respect to that X-Channel. With regard to the fixed channels you mentioned, this might be accomplished using constant curves. 

If this is not what you are looking for, can you please provide a little more detail about what you are trying to do? I don't completely understand the general case you explained.  

[mikel_jo]

Hi, thanks for the answer!

I'll give a better example of the data I currently use. The measured value is a voltage, Vout, and it depends on 3 parameters: temperature (T) and 2 other input voltages (V1 and V2). The measurement program (some custom program, not Labview) is writing the data into a TDMS file with the following structure, where each line below is a channel within a group:

T       25  25  25  25  85  85  85  85

V1       1   1   2   2   1   1   2   2

V2     0.5 0.8 0.5 0.8 0.5 0.8 0.5 0.8

Vout     x   x   x   x   x   x   x   x

Based on this, I would like to have various graphs, all with Vout on the Y axis, e.g.:

- one graph for each temperature, with Vin1 on the X axis and the graphs should have several traces, one for each value of V2

- or one graph for each V1, with the temperature on the X axis and again V2 as a parameter for the traces

I hope it's more clear now. What I'd like to know is if Diadem is able to create this type of graphs, maybe with a different structure of the data.

[Brad_Turpin]

Hi mikel_jo,

You specified the Y axis for us, but which of these quantities belongs on the X axis?.  The remaing two quantites will determine a series of logical arrays that will each contain the Y values of one of those black lines in your linked diagram, and which should each be stored in a separate Y value channel.  So you will have one X channel and four Y channels resulting from this reorganization, which will result in four XY curves.

Brad Turpin

DIAdem Product Support Engineer
National Instruments

[mikel_jo]

Hi, Brad

I wrote that in the last part of my previous message, sorry if I was not clear.

For the first case, I'd like to have 2 charts. The 1st would be for T = 25 degrees, would have V1 on the X axis and Vout on the Y axis and it would contain a family of curves, one for each V2 value. The 2nd would have the same format, but for T = 85 degrees.

[Brad_Turpin]

Hi mikel-jo,

OK, this last description from you is very clear, thank you. I would recommend that you create one Group in the Data Portal per graph, like this:

Group "T=25 degrees" with Channels "V1", "VOUTat0.5", "VOUTat0.8"

Group "T=85 degrees" with Channels "V1", "VOUTat0.5", "VOUTat0.8"

All the channels in the "T=25 degrees" Group would have values (rows) where the temperature was always 25 degrees.

All the channels in the "T=85 degrees" Group would have values (rows) where the temperature was always 85 degrees.

All the "VOUTat0.5" channels would have values (rows) where V2 was always 0.5

All the "VOUTat0.8" channels would have values (rows) where V2 was always 0.8

If you send me one of your data sets, I may be able to provide you with a VBScript that will do this rearrangement.

Brad Turpin

DIAdem Product Support Engineer

National Instruments

[mikel_jo]

OK, thank you!

I understand that it is not possible to plot the data directly from the original dataset, it needs to be rearranged so that the data for each trace is in a different channel.

I'll look into my software to see how this postprocessing could be handled. This might not be so easy, as sometimes there are 4 or 5 input variables and I do not know in advance the exact type of graph that will be needed.

[hbgmysite]

Hi, thanks for the answer!