RS232 data logging

I am trying to modify the example VI for RS232 read for data logging. Basically, trying to record my measuring guage reading data with time stamp. My modified VI logs the data but it saves only last value before i stopped the program, whereas i want it to keep reading and logging data until I stop. I am not sure where I am going wrong. I am attaching my VI with this post. could anybody help me out please.
Kudos are (always) welcome for the good post. :-)
Solved!
Go to Solution.
Attachments:
Guage data logging.vi ‏39 KB

Never mind, just figured what I was doing wrong. The create file function was in the loop so each interval it was making new file, overwritting on the previous one thus earasing all previous data but the last data point.
Kudos are (always) welcome for the good post. :-)

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I am writing regarding DAQWare, data logging software, and the PC-LPM-16
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We are a group of college students in a computer programmer/analyst
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*** Example of a capture below... ***
DAQWare File
Version: 2.0
Number of Lines in Header: 10
Comment:
Date: 10-18-1999 Time: 10:01:39
Sample Rate: 60.0
Scan Rate: 0.0
File Format: 1
Samples per Channel: 480.0
Number of Channels: 5
O3 SO2 NOX NO2 NO
4 3 2 1 0
1 1 1 1 1
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*** and so on... ***
Regarding this attempt to use DAQWare:
1. Can you tell us where this factor (8 or 12 or however many more readings
than we would expect) means, where it is read from or set?
2. Is there an updated version of DAQWare that we should download that
would be better?
3. Is there some other existing software that we can download to use to
perform basic logging of multichannel analog input to a text file (with
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I realise that the software comes with tools (DLL functions) that one can
use to create custom software to interface with the DAQ board, but in the
limited amount of time we have we are not sure we can learn enough about
these functions to write our own datalogging software.
However, to see if I could grasp the basics, I have looked through the
examples for Visual Basic and think that a program would run something like
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1. at the beginning, use LPM16_Calibrate to reset the board
2. configure acquisition with DAQ_Config
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Any help you can give to point us in the right direction would be
appreciated.
Sincerely, Marc Bell ([email protected])

I am writing regarding DAQWare, data logging software, and the PC-LPM-16
board, which a group of us a trying to come to grips with. This is rather
lengthy, I'm afraid...
We are a group of college students in a computer programmer/analyst
program. We have a course that involves doing a project to go through the
software development lifecycle (or as much of it as can be done in a term).
For our project we teamed up with a group in the industrial hygiene
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and the NI-DAQ software (all of this has been around for a few years, but
has not been used much), and our goal was to capture the data they are
measuring (atmospheric pollutants) to an Microsoft Access database.
We are not familiar with DAQ systems, but were shown the software they had
installed. This included DAQWare (appears to be version 2.0). We thought
we could use DAQWare to log data to a text file, which we then would import
into the Access database. We came up with VBA code to parse the ASCII text
file created, but have run into one problem: DAQWare does not timestamp
each sample, but only puts a single timestamp in the header information.
Now we could extrapolate the time for each line based on the sample rate,
except that sometimes it seems to put in 8 values per sample, sometimes 12
values. For instance, in the sample of a text file below, the capture was
run for 1 minute at a sample rate of 60, and there were 480 measurements in
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we got 800 measurements in the file etc.) This was two weeks ago. Today,
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*** Example of a capture below... ***
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Version: 2.0
Number of Lines in Header: 10
Comment:
Date: 10-18-1999 Time: 10:01:39
Sample Rate: 60.0
Scan Rate: 0.0
File Format: 1
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O3 SO2 NOX NO2 NO
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*** and so on... ***
Regarding this attempt to use DAQWare:
1. Can you tell us where this factor (8 or 12 or however many more readings
than we would expect) means, where it is read from or set?
2. Is there an updated version of DAQWare that we should download that
would be better?
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timestamp)?
I realise that the software comes with tools (DLL functions) that one can
use to create custom software to interface with the DAQ board, but in the
limited amount of time we have we are not sure we can learn enough about
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However, to see if I could grasp the basics, I have looked through the
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this:
1. at the beginning, use LPM16_Calibrate to reset the board
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4. loop to check is acquisition done with Lab_ISCAN_Check
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Unfortunately, a sample app using Access and VBA I created came back with
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Windows system directory); probably it is not a good idea to try to do this
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Hi everybody,
hope I can explain my problem good enough that anyone can help me:
I have a VI which continuely shows on a graph the voltage of a Analog Input of a DAQ device. Now I want to allow the user to start/stop with a click on a button data logging. Means that a second loop writes to a selected path every ms the data to a spreadsheet file.
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Logging voltage.vi ‏93 KB
screenshot.JPG ‏98 KB

@NaruF1 and GerdW
you are right, there is a mistake, both loop rates should be the same (10 ms) :-)
@NaruF1
yes you understood correctly that the file dialog should appear every time the user wants to start writing a new log-file. The voltage we measure is a analog signal, so there will be several interesting periods we want to save for a later analysis in Excel.
To your 2nd point: if it works with a array it will be fine. But it must be possible to log data for lets say 5 minutes, so the array won´t be too large? (5 min @ 10 ms loop rate will be 30000 rows..
attached is the VI, saved as LV2009..
Thanx a lot!
@GerdW
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Logging voltage.vi ‏80 KB

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Hello,
Hope someone could help with this issue. I have simple application which process ASCII data coma separated from serial port at speed of 115.2kbps. There is 6 columns of unsigned short data . I set-up COM call back function to receive data and I created separate thread function to plot data on a 6 graphs - PlotWaveform() used. Plots roll-over from beginning every time it receives more then 3000 samples. There is couple of more command buttons to set-up serial port, save data to a file, and exit application.
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Go to Solution.

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TimedWriteMeasurements.vi ‏84 KB

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break;
//trial of unpacking/unstuffing byte buffer
else if( readBuf[i+1] == 0x10 ) //two tens in a row, remove it
memmove( &readBuf[i],&readBuf[i+1],bufLen-i);
bufLen--;
//at this point, we should have a full packet. What if we don't....???
packet_length = i - start_offset;
//CmtGetLock(lock);
ParseResponse(start_ptr,packet_length);
PostPacketToOutputBuffer(start_ptr,packet_length);
if(start_ptr[start_offset] == 0x10 && start_ptr[start_offset+1] == 0xAA )
com_Send_Acknowledge(comPort);
start_offset = packet_length + start_offset;
if(start_offset < bufLen-1)
goto parse_some_more;
//For now, assume everything else we don't care about in buffer, however, probably shouldn't. Should it be bufLen -=start_offset; if so, need to handle partial data better; timeout??
bufLen = 0;
//CmtReleaseLock(lock);
skip:
return 0;
Thanks!

Hi ngay528,
I think there is a great example for you to use that comes with CVI which can be found by clicking Find Examples on the splash screen or Help >> Find Examples in your project. From there, click into Optimizing Applications >> Multithreading. In that folder there is a project that is called BuffNoDataLoss that shows how to create a thread safe queue and setup a producer/consumer type program. In this example the data is a random sine wave but could be adapted to your RS232 data. If you have any questions concerning this example please let me know but this should be a great starting point.
Patrick H | National Instruments | Software Engineer

Help In keithley 2400 VI!!(Problem with the data logging and graph plotting)

Hi,need help badly=(.
My program works fine when i run it,and tested it out with a simple diode.The expected start current steps up nicely to the stop current.The only problem is when it ends,i cannot get the data log and the graph,though i already have write code for it.Can someone help me see what's wrong with the code?I've attached the necessary file below,and i'm working with Labview 7.1.
Thanks in advance!!!
Attachments:
24xx Swp-I Meas-V gpib.llb ‏687 KB

Good morning,
Without the instrument it might be hard for others to help
troubleshoot the problem. Was there a
specific LabVIEW programming question you had, are you having problems with the
instrument communication, are there errors?
I’d like to help, but could you provide some more specific information
on what problems you are encountering, and maybe accompany that with a simple
example which demonstrates the behavior?
In general we don’t we will be unable to open specific code and debug,
but I’d be happy to help with specific questions.
I did notice, though, that in your logging VI you have at
least one section of code which appears to not do anything. It could be that a small section of code, or
a wire was removed and the data is not being updated correctly (see pic below). Is your file being opened properly? Is the data being passed to the file
properly? What are some of the things
you have examined so far?
Sorry I could not provide the ‘fix’, but I’m confident that
we can help. Thanks for posting, and
have a great day-
Message Edited by Travis M. on 07-11-2006 08:51 AM
Travis M
LabVIEW R&D
National Instruments
Attachments:
untitled.JPG ‏88 KB

Clarification on packet data log

I understand the Packet Data logs can remember upto last 30 days. What I don't
understand is are they rotating logs or do they reset to zero every 30 days. To take
an example: if I use exactly 1MB every day and my log setting is set to 30 days. After
40 days ...
- with rotating logs, I'll see 30 MB usage
- with reset-to-zero logs, I'll see 10 MB usage
So which one is it ? I'm using C5-00 on 032.010 if that matters. Thanks.

k

RS232 data logging

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