background image problem

[altenbach]

It is a major problem, but not the only problem. 😉

[Ben]

If you are interested in performance please check-out this Tag Cloud devoted to performance related threads.

If you read, understand and adhere to the tid-bits shared in those threads, you will become a giant.

Ben

[Silversky]

Ok guys first of all i want to thank you a big thank you for your support, i'm a good programmer with java and C# but in Labview i'm pretty new and with your help now my program speed like a Ferrari, i've reduced the property node in function generation to only 1 😄 and i've rewritten the scope-vi like Altenbach suggest me and now it's all clean and smooth, but there is a problem that i can't solve alone because i'm not familiar with Feedback node. The problem is that when i change the offset in the Y or X on the graph the value show don't match the real value and strange things happen. Can you help me with this issue? Thanks so much.

[altenbach]

OK, that looks much better. You still have useless value property nodes for the offsets. Delete them and wire the terminal directly in their place. Indicators retain their data until they are overwitten with new data, so there is no need to place them outside the case structure.

For the offset problem, you need to play around a little bit. Here is some background:

The axis scale ranges determines which part of the data is in the visible range of the graph. For example if you have data from 0..1000 and set the max to 500, you'll only see the data from 0..500.

Offset and multiplier are completely different. They are useful if your graph data is a simple 1D array and has no x information. The offset and multiplier define the mapping that translates array index to the actual X value. For example if x0=5 and dx=2, the first element of the array will have x=5, the second will have x=7. etc. If you change the offset, the range will be different and needs to be reset.

Here are a few things to try:

You have waveforms, so the timing data is already included and the offset might thus not be consistent.

In the graph properties there is a checkbox to ignore timing data, try to enable it.

Since the range and offset/multipliers are interacting parameters, you might also want to change the order of the properties. Set the offset first and then set the range. See if it makes a difference.

I actually believe that all you should do is change the range. Leave the offset at 0 and set the offset indicators to halfway between max and min, for example.

Sorry I am a big vague.... just play around.

[Silversky]

Thanks Altenbach, are you maybe a developer of Labview? You know all 😄 i've swapped the offset first and range after and all now work like a charm. Now i'm going to implement the trigger function and after the FFT. Do you think Altenbach that the express vi Trigger&Gate is good to implement the trigger function that show the signal stable on the screen (Trigger locked on the signal)? Thanks sorry for all the questions!!