help needed-- error code 1815

[gupta.nitesh87]

i m using 'visa configure serial port' followed by 'visa read' to take input from com1 port. The received signal is spreadhead string. i need to convert it to digital waveform for further processing. there is a VI available for this named 'spreadsheet string to digital.vi'. but while using this VI for the conversion, i m getting an error as given below

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Error -1815 occurred at DTbl Spreadsheet String to Digital.vi

Possible reason(s):

LabVIEW:  An invalid character was present in the spreadsheet string. Use only 0, 1, L, H, X, Z, V, or T.

Complete call chain:
     DTbl Spreadsheet String to Digital.vi
     DWDT Spreadsheet String to Digital.vi
     visa read.vi

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I need your help to solve this problem. its very urgent for my project

Message Edited by gupta.nitesh87 on 05-05-2008 07:12 AM

[MikeS81]

Hi gupta.nit…,

check your string for the invalid characters. Can you upload your vi, because it´s easier to see what you have done?

Mike

[Ray.R]

You should try "Spreadsheet string to array".  You can set the array to your desired numeric format (ie: Double, etc).

Depending on how you do your acquisition, you may want to build your array until it is ready to be processed, plotted, etc.

RayR

Message Edited by JoeLabView on 05-05-2008 08:22 AM

[gupta.nitesh87]

i m uploading the vi here

[MikeS81]

Hi gupta.nit,

i thought you can upload the vi in the same configuration as you use it, can you? I see no "Spreadsheet String to digital" function. Can you upload it with some characters you have already received?

Mike

[gupta.nitesh87]

sorry mike. that was my mistake.

now i m uploadig correct vi.

[gupta.nitesh87]

One more thing I want to tell is like our data is coming from a microcontroller that is sending all 000-FFF and without ant delimiter. So suggest any other visa read vi which can directlr take in binary or as byte instead of reading it as string.

[smercurio_fc]

There is only 1 VISA Read, and it returns a string. It's up to you to deal with that string. You state:

our data is coming from a microcontroller that is sending all 000-FFF and without ant delimiter

So why are you trying to use the Spreadsheet String to Digital Waveform VI? If you have no delimiters, then that VI won't work.

It seems to me that what you actually want to do is typecast the data recveived from the microcontroller as an array of numbers. You did not provide a sample of what you're actually receiving from the microcontoller.

[gupta.nitesh87]

Actually we dont want it in string its just that we found only VISA read VI to take data from device connected through com1 port which stores in buffer as string by default. What we are recieving is a signal recording some heart beat pulses and we want to have it displayed in amplitude time graph. When we are seeing on other oscilloscope programs its showing nicely but we are facing problem in labview possiblly due to these data format mismatch. Its showing YYYYYYYYYY in read buffer and when we are tring to convert in byte array and converting in digital waveform it gives Error -1815 occurred at DTbl Spreadsheet String to Digital.vi LabVIEW:  An invalid character was present in the spreadsheet string. Use only 0, 1, L, H, X, Z, V, or T.

[Ray.R]

If you are getting strings of "YYY", the it doesn't meet the criteria.  You can only use 0, 1, L, H, X, Z, V, or T.

So as Smercurio stated, you cannot use the Spreadsheet string to Digital waveform.  You have to deal with the string in a different manner.

Use the VISA Read to get the serial data.  But you must then handle that before you try to plot it. 

In order for anyone to propose something, we would need to see an unmodified version of the received string straight from the serial port.  You could save it in a text or binary file, whichever is more appropriate and post it in this thread. 🙂

Message Edited by JoeLabView on 05-05-2008 01:01 PM