Re: Displaying waveforms

[hill@luke.atdiv.lanl.gov (Jeff Hill)]

Hello all,

> 
> double waveform_array[16384];
> assign waveform_array to "WAVEFORM_ARRAY.VAL";
> 
> /****** Acquire data and stuff it into an array: this part  *****/
> /****** works because I can print out believable data using *****/
> /****** the printf statement below.                         *****/
> 
> /* write to waveform */
> %%	array1_ptr=lpanarray1;
> %%	for(count=0;count<lnumsamples;count++)
> %%	  {
> %%		waveform_array[count] = (double)(array1_ptr[count]*3.091e-10);
> %%		printf("%e\n",waveform_array[count]);
> %%	  }
> 	pvPut(waveform_array);
> 
> 
> My database file for this record looks like this:
>  
>     record(waveform, "WAVEFORM_ARRAY")
>     {
>         field(DESC, "Array for HP positions")
>         field(NELM, "16384")
>         field(FTVL, "DOUBLE")
>     }
>     
> Instead of putting this array into my waveform record, the dang computer 
> prints the error message: 
> 
> error from CA on WAVEFORM_ARRAY.VAL
> The array or data structure specified will not fit in CA message buffer
> 
> Any ideas what's wrong? Thank you very much!
> 


You are experiencing the infamous Channel Access array element count 
limit.  Channel Access limits network transfers to roughly 4k 4 byte 
elements (or 2k 8 byte elements). When the Channel Access client and 
the process variable are located within the same host then this limit 
does not apply. This is why your sequence program does not see the 
limit (the sequencer also uses channel access client library).

My priorities at this time are:
1) finish the new ca server
2) remove the ca array element count limit 


Jeff


______________________________________________________________________
Jeffrey O. Hill			Internet	johill@lanl.gov
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