Operating Modes

 When you start LabHelper X, it asks you which A-D converter to use (the UI2-specific version skips this step):

In this example, the user has chosen the Sable UI2 (click the 'OK - close' button to finalize this selection, or click the 'Test/demonstration mode' button to proceed with a simulated A-D converter.

Before LabHelper can acquire data, it must be given a sampling protocol which includes:

  • the recording mode
  • the number of input channels
  • sample rates
  • the duration of sampling
  • matching of logical with hardware channels,
  • signal processing and voltage conversion
  • signal averaging method
  • control of external devices
  • triggering options
  • screen appearance options
  • alarm settings
  • audible timer

The initial input window of LabHelper (shown at right) offers a choice of 1 to 16 channels in four modes of operation:

  • Chart
  • Oscilloscope
  • Oscilloscope plus chart

You can also load a 'setup file' with a complete pre-recorded sampling protocol (setup files are stored from the OPTIONS window).

  CHART MODE gathers a fixed maximum amount of data from 1 to 16 channels (up to a million cases); the operator can intervene at any time to stop acquisition before the maximum number of samples is obtained.  The computer automatically selects the optimal gain on each channel to maximize resolution.  Data are plotted as line graphs, with a separate graph for each channel.  Data are stored either under manual supervision (i.e., the operator selects a new file name for each set of data) or automatically under the autorepeat option.  In autorepeat mode, the operator provides a 'root' file name before data acquisition starts.  Subsequently the program automatically saves data whenever its buffer is full, appending sequential suffixes (1, 2, 3, 4, etc.) to the file root name for each save.  Sample rates for single channels can be as fast as 500/sec (or more) if you have a fast CPU, but are slower (again depending on machine type) if the number of channels is large.

  • If you are using an ADC-1 or DataTaker, the maximum sampling rate is about 3-4 samples/second, depending on input voltage and machine type. 

  OSCILLOSCOPE MODE works like a typical oscilloscope.  At low to moderate sampling rates, data from a single channel are plotted from left to right.  Whenever the next point would 'fall off' the right edge of the screen, plot position is swapped to the left edge and each new point 'erases' the previous point at that x-coordinate.  The operator provides a 'root' file name before data acquisition starts.  Whenever the TAB key is struck, the existing screenfull of data is saved under the root name plus a sequential suffix number (see detailed description in the SETTING UP section).  An oscilloscope screen can contain up to 65,500 samples.

  • If you are using an ADC-1 or DataTaker, the maximum sampling rate is about 3-4 samples/second.  Therefore, oscilloscope mode is NOT available.

  OSCILLOSCOPE PLUS CHART MODE combines one oscilloscope channel plus one to four chart channels.  Note that sampling rates for oscilloscope and chart channels are usually different.  Because this mode is a combination, it is also a compromise: The oscilloscope channel cannot sample as fast as in 'pure' oscilloscope mode, sample averaging is keyed to the sample rate of the oscilloscope channel, a total of only five channels is permitted, autorepeat is not available, and sequential switching of external devices (see below) is not permitted.  You should also be aware that if the chart channel sample rate is high, chart timing may be affected by the time lost when oscilloscope screens are saved to disk.  If you are saving to a hard disk, the latter problem is usually not significant unless chart sampling intervals are less than 1 second or data files are very large.  The TAB key saves oscilloscope data, and the ESC (escape) key permits you to stop sampling to adjust sample parameters or save chart channels.  Large screens can contain up to a million samples.

  • If you are using an ADC-1 or DataTaker, the maximum sampling rate is 3-4 samples/second.  Therefore, oscilloscope plus chart mode is NOT available.

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