LabVIEW
Temperature has stabilized after determinate time?
Hi aaswil,
@aaswil wrote:
- Do you really need to read Pt100 sensors this fast? Does your DAQ device even support such sample rates? (Which hardware do you use?) Daq 9216
Please read the datasheet for your NI9216! It only allows upto 400S/s (high-speed mode) or 5S/s (high-resolution mode)…
@aaswil wrote:
I still don't understand how the DAQ 9216 data will be represented graphically.
They will be shown in the graph labelled "no label!"…
@aaswil wrote:I'm amazed at how clean your codes are.
Simplicity is the Ultimate Sophistication- Leonardo da Vinci (ydraw.com)
Very relevant to programming. Simplification should be a constant concern.
@aaswil wrote:
- Do you really want to read "finite samples" - or do you intend to use "continuous samples" in the DAQAssistent? Using a loop suggest you want to read samples continuously… Continuously
That's a problem. The data is continuously added, so at some point you'll run out of memory.
@aaswil wrote:I still don't understand how the DAQ 9216 data will be represented graphically.
Do you only want to show it in a graph?
That isn't too much off from what you have.
But as your dT is constant, you probably don't need to keep the time at all.
A chard will take an array of (scalar) points, and keep history on it's own. So you also won't need to keep an array of history.
GerdW might cook up something. (EDIT: That crossed) (BTW: Do you know about kudos?)
Search LabVIEW like a graph!
wiebe@CARYA wrote:(BTW: Do you know about kudos?)
Just gave you your first!
Pass that glorious feeling to people helping you. (EDIT: I meant GerdW of course, but Thanks!)
@aaswil wrote:
I was able to measure the temperature using the Daq 9216 and plot the graph,
Great!
@aaswil wrote:
now I need to show a table of each channel within the labview indicating the history of the measured values with an interval of 30 min, I also need this when there is a variation of less than 1 °C at the temperature of a given channel for 3 hours, the labview indicates the stabilization of the channel, i also need to know how much each channel has changed since the last measurement (eg in the last 10.15 or 30 min)
You'd need to start buffering the data to get those stats. The table might be tricky. That's a lot of data to be updating on the screen. Note that nobody would be able to read it, as it will be updating continuously.
With the amounts of data you have (200 Hz? X n X 3 X 60), it will be very wasteful to continuously add to an array on the end, and remove from it's beginning. This will make LabVIEW copy the array over and over. You'd probably be able to get a way with it, modern PCs are very capable, but it will be wasteful.
I'd suggest some sort of circular buffer.
This can be done in different ways. The 'right' way is very much a matter of experience and goals.
You can make a Function Global (FG or FGV). It would have an add function that adds new data, and one or more functions to get the statistics from it.
You can do the same (but better 😋) with a class. Put the data in it's private data, add methods to add, and get stats.
You don't want to go back to buffers (shift registers) with all the data in the main. This will mean all handling of the data in the main, and the main will grow, and grow. This will make the main unmaintainable (pun intended).
@aaswil wrote:
finally save the results (graphs and tables) in Excel.
That's a (non-trivial) topic on it's own.
I'd avoid this at all costs, as your application will be strongly bound to the exact Excel version used at compile time. At least, AFAIK, if you use the report generation toolkit. I don't have a good alternative...
Hi aaswil,
@aaswil wrote:
now I need to show a table of each channel within the labview indicating the history of the measured values with an interval of 30 min, I also need this when there is a variation of less than 1 °C at the temperature of a given channel for 3 hours, the labview indicates the stabilization of the channel, i also need to know how much each channel has changed since the last measurement (eg in the last 10.15 or 30 min) finally save the results (graphs and tables) in Excel.
So what have you tried so far?
What is the problem to display values in a table?
Do you really want to use a table indicator, or a MultiColumnListbox, or an array indicator?
Do you really need to save "in Excel"? Would it be sufficient to store your data in TDMS or simple text files (aka CSV files)?
Please be as specific as possible when discussing problems!
Please provide your current VI. Show the attempts you made to tackle your problem.
