Daqarta for DOS Contents



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Daqarta for DOS
Data AcQuisition And Real-Time Analysis
Shareware for Legacy Systems
(Use Daqarta for Windows with modern systems)

From the Daqarta for DOS Help system:



You may store and recall multiple traces in internal memory for quick access. This can be especially handy if you want to follow trends or make comparisons, since only two keystrokes are required to select any trace for display, and a whole series of traces can be displayed at once using the Memory Array option.

The traces are stored with all relevant parameters and the comment line, just as they would be saved to a disk file with OutDt. You may store any mix of waveform or spectrum traces, averaged or instantaneous, having any number of points N. DDisk recordings may not be stored in their entirety as memory traces, although you may store any selected screen just as you could use OutDt to create a file from it.

Traces are stored sequentially, with ID tags given by a single character starting from 0 to 9, then A to Z. Traces beyond these 36 are selected with an ALT-key plus the character, and are labeled A0 to A9 and AA to AZ. Beyond these, use CTRL to get C0 through CT, for a maximum of 102 traces. That limit is fixed by the size of the buffer reserved for memory storage, which is 64 Kbytes (65536 bytes) of "hidden" video memory that would otherwise be wasted. The amount of this memory required to store each trace depends upon the type of trace (which determines data size per point), and the number of points N used... plus a 128 byte parameter and comment header:

                  256 pts       512 pts       1024 pts

 Inst Waveform    640 bytes     1152 bytes    2176 bytes
 Avg Waveform     1152          2176          4224
 Inst FFT         640           1152          2176
 Avg FFT          896           1664          3200

So if you were storing only 1024 point waveform averages, you could fit 15 traces into the 65536 byte memory area, whereas if you had only 256 point instantaneous waveforms you could use the maximum of 102 traces. In practice, you will probably find that you rarely need more than a dozen traces.


To save a trace to memory, hit SHIFT-M. If the trace was Live, it will be automatically Paused first. You will be prompted for a sequential ID to save the trace as, starting with 0:
  'Save to Mem 0 ?  (ENTER, ESC, or Mem 0)'
If you hit ENTER, the prompt ID will be used, which may also be entered directly by just hitting the 0-key. ESCape will cancel the save operation. After the initial save, subsequent saves give a different prompt:
  'Save to Mem 1 ?  (ENTER, ESC, or Mem 0 to Mem 1 {END})'
The prompt ID will now be one more than the last trace saved or read. Here you can ENTER or ESCape as before, or hit 0 or 1 to save to that respective trace. If you select a trace that already exists (0 in this case), that trace will be overwritten by the new trace. Since this system is designed for quick operation, there is no separate write confirmation step, so make sure this is what you really want to do.

If you hit the END-key instead of ENTER or a direct ID, you will automatically select the next free ID past the maximum in use, so you will never overwrite prior data. Of course, there is no need for this if you are just sequentially saving traces from scratch, since you will be prompted with that ID anyway and can just hit ENTER. But after you have saved several traces and you decide to go back and review or overwrite an earlier trace, the prompt will be one more than that trace. For example, if you have saved Mem 0 through Mem 4 and then overwrite Mem 2, the next time you hit SHIFT-M to save a trace the prompt will be:

  'Save to Mem 3 ?  (ENTER, ESC, or Mem 0 to Mem 5 {END})'
Here you can rely on the END key to select the next trace, shown here as Mem 5. You never need to remember where you left off with the original saving sequence.

When you overwrite an existing memory trace, Daqarta will slide things around to make room if the new trace is bigger than the one it is replacing, or to compress space if the new trace is smaller.


After you have saved one or more traces in memory, you can review them by hitting the unshifted M-key. If the current trace is Live, it will be Paused first. If there is only a single trace in memory, the prompt will be:
  'Recall Mem 0 ?  (ENTER, ESC, DEL, or Mem 0)'
Here you can hit ENTER to select the prompted trace or hit the 0-key to select it directly. (You can also hit ESCape if you change your mind.) When the recalled trace is displayed, the status will show 'Mem 0'.

If there are multiple traces in memory already, you will be prompted with the most recent addition, or most recently read. If you have saved traces 0 through 4 and have recently recalled trace 2 (but it is not now on the screen), the prompt will be:

     'Recall Mem 2 ?  (ENTER, ESC, DEL, or Mem 0 to Mem 4)'

If you hit MemRd while you are currently viewing any memory trace, you will not see either of the above prompts. Instead, the 'MemRd' option will change to 'Mem' with a small double-headed vertical arrow as a special prompt. This will allow the up and down cursor keys to scroll through all traces in memory for rapid review. When you find the one you want, ENTER or ESC will accept it.

Daqarta also offers the Memory Array mode to see multiple traces at once, which you may prefer to use instead of MemRd scrolling. However, that option can only display comparable traces together on one screen, whereas with MemRd scrolling you can scroll through all the traces in memory. You can use MemRd scrolling to select the base trace for the Memory Array.

During MemRd scrolling, you still have the option of directly selecting any trace by its ID number. If you want to see the full-range prompt as before, you must ESCape and unPause to clear the exiting memory trace from the screen, then hit MemRd again.

When a trace is recalled, Daqarta will change the screen display mode in an attempt to accomodate the recalled trace in the current mode. If the recalled trace was originally a single or averaged waveform or a single FFT, it will have been stored as a waveform. It can thus be displayed in either waveform or spectrum mode (since Daqarta can take the FFT of the stored waveform data). But if the trace was an FFT average, Daqarta can't convert it back to a waveform... the display will be forced to FFT mode. If you try to change to waveform mode after the trace is displayed, you will see:

  'FFT data only.'
There is no "inverse FFT" function in Daqarta.

While a recalled trace is being viewed, certain control menus will be restricted by removing the cursor, or access to certain menu items blocked by limiting cursor motion. This prevents changes to the record of parameter settings for that trace. The ADC Board menu will be replaced with the Trace Info menu.

One notable execption is the comment line... you can Edit it and then use MemSv to send it back to the same ID, if you wish. (Note that this will be one less than the prompt ID.) When you do this, however, Daqarta treats it as a "new" trace and updates the time record.


To delete a trace and all traces above it, invoke MemRd and display the selected trace. Hit the DEL-key and you will be prompted with:
  'Delete Mem N and above? (Y default/N):'
where 'Mem N' is the selected trace ID. Hitting any key other than Y or ENTER at this point will escape the operation.

If you hit Y or ENTER the trace and all above it will be deleted, and the next lower trace will be displayed in its place. If you had selected Mem 0 to delete all traces, the "ghost" of Mem 0 will remain in view (since there is no lower trace to show) and the status indicator will change from 'Mem 0' to 'Mem ?' as a reminder that it is not really in memory.

Since traces are always stored with sequential IDs, there is no provision for deleteing individual traces other than the top one. This avoids the confusion of either changing all the IDs to close up gaps, or trying to remember where the gaps are. Note, however, that you are always free to use MemSv to overwrite any trace with new data.


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