Few questions about LabView and thermocouples ( rather complicated )

[sprzysta]

Hi again 🙂

In my personal opinion using DAQmx API for acquiring the signals is more flexible than using DAQ Assistant.
DAQ Assistant is ok if you wan to only read data and visualize or save to file.
When you are using DAQmx API you can configure from level of LabVIEW what kind of data You want to to receive.
Changing the names of the thermometers is not a problem. You can change convert array to cluster and then every element in the cluster can have a different name and even have a different type.
Im attaching the example.

Of course if Your solution is working is also great. The choice is Yours depending on Your requirements 🙂

And don't sorry for learning

Please write a feedback

Regards

[Galjuntur]

Hi sprzysta,

thanks for your strong commitment to my topic. I'm trying to make my program quite simple because my knowledge is simple so that's why I use daq assistants. Nevertheless, I think, I'll make two versions of my program. ( with daqs and with your solution ) Firstly I would like to have a working base that I know to have clear mind and then I would start with improving it with your tips.

I think, I will need to implement cursors and that is impossible for waveform charts. I found the VI with such code but I suppose that I have to convert the data again. I'm worried if the channel names will still work after the conversion. ( Dynamic Data needs to be converted to DBL, right ? )

BTW Is this possible to make an option which will allow to see the difference between values of the channels from the last hour up to the present time ?For example my reading took 2 hrs, and I would like to check the difference ( on each channel )  between the end of the "experiment" and the last hour. ( after my data reading is ended )

[sprzysta · Accepted solution]

Hi

You don't need to convert data because Waveform Graph support dynamic data type.

In Your case using Waveform graph don't have sense because Waveform Graph is designed to display series of samples.

Below you can find nice tutorial about Waveform Graps and Chaarts

https://www.youtube.com/watch?v=HtjgeoJc4zA

http://digital.ni.com/public.nsf/allkb/95FEE9F5B252507E862562BA00007657

http://zone.ni.com/reference/en-XX/help/371361J-01/lvconcepts/types_of_graphs_and_charts/

About Your second question the simplest way is to post process acquired data.

If I would be You I will just read series of data from file(after finishing of the measurment) and then I will just chose (with controls or cursors, the choice is Yours)

whitch samples I want to compare.

Please look into provided materials and LV basics tutorial this will help You to define what You realy need, because there are multiple ways to

answer Your questions but finally You need to choice what is the best for You.

Please write a feedback

Regards

[Galjuntur]

Right, thanks for tutorials. I looked into them once again. I realised that I wrote a silly thing but forum doesn;t allow to change answers after some time. 

As I said, I was planning to add cursors which is impossible on charts. I read that you can only zoom in to get the exact value. ( at least values will be saved to a file so it has to be done manually )

Graphs show series of samples but what if I set the amount of samples that would equal the total number of samples, gathered during the reading ? Lots of computer resources could be consumed probably.