LabHelper has five active menus available when the program is not busy gathering data. Note: In Mac OS 8 or above, the "Help" menu contains LabHelper's on-line help option (it's in the Apple menu in earlier operating systems), and several calculator functions useful for open-system respirometry.
| FILE | EDIT | VIEW | A-D | D-A |
CUSTOM CONVERSIONS 
+Z Permits entry of custom voltage
conversions to suit the user's instrumentation. There are two ways
of doing this:
You can transfer your existing channel parameters into custom voltage conversions, complete with buttons. To do this, select the "transfer current conversions..." button in the initial selection window, and the following window will appear:
Click the appropriate button to change, and the current channel label and conversion values to use with the new button, and push the "save this change" button. When done, click the "Conversions OK" button. This option is not available for the 3-order polynomial conversion. If you want your newly-transferred conversions to appear as buttons the next time LabHelper is run, you must store them by pushing the 'Save conversions' button in the following window.
Alternately, you can directly enter the various parameters (a, b, and c values, scaling limits, labels, etc.) in the custom conversions window (this window appears after you exit the 'transfer conversions' window). By pushing the 'Save conversions' button, you can store the new values in a preferences file. If you use the filename 'LabHelper prefs' and store the prefs file in the same folder as LabHelper itself, your selections will be loaded and used at startup. This sample custom conversions window contains the default values, but you can enter your own button and channel labels, conversions, and scaling limits:
CUT TEXT +X
CUT, COPY, and PASTE work in the standard way,
but only on text (and not on other program items). COPY TEXT +C PASTE TEXT +V
PLAY SOUNDS +A Toggles the sound
function. If sound is on, the program uses custom sounds to call attention
to important events. If sound is off, the current Macintosh alert
sound is used in situations when it is really important to attract
your attention..
DATA FILE INFO +I This option allows
editing of the comments and data stored with each file (in most cases, this
option is offered automatically when files are saved):
This option is not available unless you have selected binary file mode (a more limited view, with just the comments available for editing, is used with Sable-format files).
RATE RECORDS PRECISION
Activates a window that lets you adjust the 'margin
of error ' for saving the sample rate of chart channels. The default
is ± 3% -- that is, if an "actual" sample rate (as calculated
from the time recording starts and ends) is within 3% of the user's
requested rate, then the requested rate is stored in the data file.
If the calculated rate differs from the requested rate by more than 3%,
an warning is shown and the calculated rate is saved. This window
lets you change the acceptable error to values other than 3%.
| The following four selections are only available after a recording mode has been specified (either from the 'Recording modes' window or from a setup file. |
CHART SAMPLE RATE...
+R
Opens a window that lets you set
the sample rate and recording time for Chart channels.
SCOPE SAMPLE RATE...
Opens a window
that lets you set the sample rate and recording time for Oscilloscope
channels
EXTERNAL DEVICE
CONTROL... +E Opens a window
that lets you specify how digitally-activated external devices will be controlled
during sampling.
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