Display Setup

Overview	Testing channel parameters
Adding and deleting channels	Chart channel display control
Scope channel display control	Adjusting channel plot heights
Adjusting the number of samples	Autorepeat

• In Oscilloscope and Oscilloscope plus Chart mode, some edit fields are 'fixed' and cannot be changed.  These have a dark gray background.  In Multichannel Oscilloscope mode, ALL edit fields except the channel labels are fixed. 
• Note that a channel used for the keyboard event recorder must have an A value of -9999.  The B and C values are not used. 
• If you are using a 3-degree polynomial conversion for a channel, the A, B, and C values for that channel will be replaced by a button labeled 'Polynomial conversion'.  Click this to change the polynomial variables, the factor used to convert input volts to millivolts, and the "scaling" factor to be applied to the result. 

  In Chart mode, the number of readings averaged for the final channel is shown as a button instead of an edit field; if this channel is set for continuous readings until the time of the next sample ("Continuous averaging" mode) the button reads 'cont'.

  The CONVERSIONS menu is accessible.  This allows you to use the regular Voltage Conversions window to adjust the voltage conversion parameters on each channel (except for oscilloscope channels, which read raw input voltage only).  You can also access the set alarms window to configure an appropriate alarm setup (see the MENU section for details).

  To test the voltage conversion and display parameters for any channel, click the appropriate "Chan.  #" button in the leftmost column.  A window will open showing a scrolling display of the current input values on the selected channel:

This will allow you to adjust any voltage offsets, gains, etc.  before starting a data acquisition run.

In the FP version, you can switch between fast and slow updating by pushing the 's' key (slow updating is often more readable).

   In Chart mode, Scope plus Chart mode, or Multichannel Oscilloscope mode, you can add or delete channels with buttons in the lower left corner.  This example shows one channel being removed from a 4-channel setup:

You cannot add beyond 12 channels in Chart mode (5 in Scope plus Chart mode and 4 in Multichannel Oscilloscope mode), and you cannot cut to less than 1 channel in Chart mode (2 in Scope plus Chart or Multichannel Oscilloscope mode).

   You may also change the sample interval (both the oscilloscope and chart channel intervals can be changed if you are in Oscilloscope plus Chart mode), the control of external devices (see below), or restart LabHelper from scratch (this is useful if you want to load a setup file, or change the recording mode).

  The button called 'Chart View' opens a window that allows selection of the 'density' of data plotted in chart mode:

The normal view contains one sample per pixel on the x-axis.  However, you can select compression ratios of 2, 2.5, 4, 5, and 10 (these options are available only if the number of chart samples is greater than the number of samples per screen).  Thus with a 640-pixel-wide screen, up to 6400 samples can be shown on a single screen.  The range is 832 - 8320 when using an 832 pixel-wide screen, and so forth with larger screen sizes.

Using the more compressed views increases the amount of recording time that fits on the screen, but at the same time the screen resolution is decreased (for viewing only; not recording) because several samples are plotted within the same x-axis pixel position.

Some combinations of view compression and maximum sample number may generate fractional time units on the X-axis of the chart display.  However, you can manually adjust the scaling of the 'time tics' on the x-axis (if they are used) with the 'use custom tic unit' button.

If the number of samples is greater than can be shown on a single screen, the chart display must be scrolled when the data plot reaches the screen's right edge.  The default scrolling value is 100% -- that is, the entire screen is redrawn, showing none of the previously-acquired data.  Alternately you may select fractional scrolling (50%, 67%, or 75%), which leaves some of the previously-acquired data in view.

  The button called 'Scope View' opens a window that allows selection of the 'density' of data plotted in chart mode.  It is similar to Chart View, except that it offers options to show only a fraction of the gathered data (all will be saved if a file is stored).  This can greatly increase the display rate (and hence the fraction of total time spent in sampling data).  Note that you should use the "show every point" option UNLESS in discontinuous or multichannel oscilloscope mode:

   A button called 'Plot Height' (not accessible in Multichannel Oscilloscope mode), allows you to divide the screen up among the different channels according to your own preferences.  For example, you can show some channels in large vertical scale and others in much smaller scale.  Note that because there is a fixed amount of screen space available, making a channel larger than normal requires shrinkage of other channels:

To set channel heights, move the cursor within the simulated plot area until it is at the desired height, then click.  The program steps through the channels in sequence.  When all channels are complete, you can accept the results, use normal values (all channels with equal heights), or redo the selection.  The program always reserves a minimum amount of space for any remaining channels (20 pixels high).  Channel heights do not affect other aspects of the data acquisition process.

  The maximum number of samples to be gathered in chart mode before LabHelper stops to save the recorded information on disk (up to 32,760).  The value can be incremented in units of screenwidth pixels.  These buttons are not available when in Oscilloscope mode.

   The number of samples in a scope screen (in Oscilloscope, Oscilloscope plus Chart, or Multichannel Oscilloscope mode).  The choices are 640 up to 32,760 (depending on the size of the screen).  The value can be incremented in units of 640, 832, etc.  depending on screen width.  These buttons are not available when in Chart mode.

  Whether or not the computer beeps at each sample (not available in Oscilloscope or Multichannel Oscilloscope mode, or at high sampling rates in other modes).

  The AUTOREPEAT option.  Autorepeat (available in Chart mode only) allows LabHelper to automatically save data when the maximum number of samples has been recorded, and then automatically restart data gathering.  If this option is selected, a standard Mac file opening dialog will appear, requesting a file root name.  Saved files will have a name consisting of the root (e.g., 'bird data') plus a suffix corresponding to the sequence number (e.g., 'bird data 1', then 'bird data 2', then 'bird data 3', etc.) of the file.

WARNING:  if you selected a large number of samples, be sure you have plenty of disk space available to save the expected number of files!

After the file root is selected, LabHelper presents a window for entering a comment string and data for gas exchange calculations (body mass, flow rate, barometric pressure, etc.).

If you are in Oscilloscope plus Chart mode, a button for Automatic markers is displayed at the bottom left of the screen.  If this button is ON, LabHelper will insert a marker into the chart files whenever an oscilloscope screen is saved.  These markers are a sequence of numbers from 0 to 9, which repeats up to a total of 640 markers.  You can also enter markers manually by pushing any letter or number key.

   Edit these values as necessary (or ignore them if they are not relevant), then click the 'Setup OK' button.

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