shuoshuo

I think I can see what's happening - LabVIEW is what's called a dataflow language - the data flows from one node to another. I can't run you code (still a whole of stuff missing, and I don't have the hardware anyway), but it looks like at least your lock-in amplifier is running, but then doesn't output the data (that's why you're not seeing any data). It's not really set up to be a subVI (like a subroutine) that does some work and returns some data, but rather a top level VI where you do everything (the hint is that it needs user interaction to work). Your top level vi (2in1) calls the lock-in amp vi as a subVI and waits for it to finish to get the data out. That's one very important facet of dataflow programming: the express vi that sets up your x-y graph won't operate until it has data at all of its inputs.

You might want to spend a little time checking this out...

hi, crelf,

Thank you for you help. I can got the output data from both lock-in amplifier and temperature in labview, i think i understand how to use x-y graphs, thank you very much.

shuo shuo

You VI couldn't be simpler, but you didn't include the 2 subVIs (modbus021.vi or lock-in amplifier.vi) or any of their sub VIs. My guess (and it's only a guess since I can't see the data) is that either of those VIs isn't returning anything. Put a probe on the wires coming out of those and let us know what the values are.

Also, an XY graph is a graph of X values against Y values - the wires suggest that the subVIs give out only one number each and not 1 dimension arrays of values...

oh, thank you. do you think i should use 1d array, not DBL value, i can change it. but the problem is that, when i use this subvi , i insert the probe on both wire, there are nothing happend, in other words, there is no value, always 0. But the lockin amplifier Vi and temperature VI are running fun, no errors, and have values.I don't know why.

here is my lockin VI and temperature VI, and the lockin amplifier driver.

Thank you for ur help.

shuoshuo

Download File:post-5682-1156512768.vi

Download File:post-5682-1156512789.vi

Download File:post-5682-1156512825.llb

Please show us what you've tried and we'll try to help out.

Hi, thank you for you reply.

I built the 2 Vis, one is indicate the temperature and other one indicated the resistance, when i try to use subvi to plot the two kinds of data in xy axies, there are nothing. as you can see from the graph below, the value of the probe are both zero, i don't know why, can any one give me some ideas?? thanks lot. :worship:

Hi, thank you for you reply.

I built the 2 Vis, one is indicate the temperature and other one indicated the resistance, when i try to use subvi to plot the two kinds of data in xy axies, there are nothing. as you can see from the graph below, the value of the probe are both zero, i don't know why, can any one give me some ideas?? thanks lot. :worship:

sorry forgot the VIs.

Hi, thank you for you reply.

I built the 2 Vis, one is indicate the temperature and other one indicated the resistance, when i try to use subvi to plot the two kinds of data in xy axies, there are nothing. as you can see from the graph below, the value of the probe are both zero, i don't know why, can any one give me some ideas?? thanks lot. :worship:

sorry forgot the VIs.

sorry wrong one!!!! this is correct!!

Download File:post-5682-1156429804.vi

Download File:post-5682-1156429874.vi

In the Main menu go to Help>Find Examples... It's full of codes that you can use/modify/combinde to your needs and they are usable (not like some MS-helps )

I did look the help, thank you anyway. i try few ways, but doesn't work. I think there are some problems about access data.

hello, everyone, i am new here.

I am try to plot a graph with x axies(resistance), y axies(temperature.)the data both are DBL 64bit. Can any one give me some ideas how to do it?? thanks lot

best wishes

shuoshuo

hi, thanks for you help! :thumbup: It is works very well. But i still have a small problem. how can I call the saving, I mean when I need to save the graph it will allow me to save(not with while loop, i know the way with while loop. ) Can anyone give me some help!! thanks lots.

Download File:post-5682-1153927815.vi