Menus (non-FP versions)
BINARY DATA FORMAT When this is selected, data files will be
saved in the default binary format. Binary files are small, contain
comments and header data, and are saved and loaded very rapidly -- almost
instantly if the computer has a fast hard disk (see the file
formats page).
ASCII DATA FORMAT When this is selected, data files will be
saved in text format. This is a much slower and more bulky method
than binary storage, but these files are more easily created and read by
other programs. Scope files start with the sample interval
in seconds and consist of a single 'column' of voltage values separated
by 'returns'. Chart files start with a list of variable names.
The first column is the elapsed time in seconds, and the remaining columns
(separated by tabs) contain the different variables. Note:
comments and other header data are NOT included in ASCII files;
you must use the binary file format to save these data.
SABLE SSCF FORMAT This option allows data to be saved in the
"SSCF"
format used by the Sable Systems
acquisition and analysis package that runs on DOS - Windoz computers.
SSCF is a binary format (the IEEE floating-point standard) that is compact
and fast. With LabHelper, SSCF files can be saved almost as
quickly as Warthog binary files. SSCF files do contain sample interval
data, comments (a maximum of 240 characters), and start date and time information
-- but they lack channel labels and the other header data that are standard
in Warthog files.
Note: SSCF files can be read by LabAnalyst,
as well as by Sable software on PCs. If you save files in SSCF, they
will appear (on a Macintosh) with their own special icon:
DATA FILE INFO 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).
TIMED DATA SAVES This option sets up an automatic backup function
during data acquisition runs, which helps safeguard data from program or
system crashes, power failures, and other potential catastrophes.
At very high sampling rates and short acquisition periods, automatic backup
is of limited utility (and can actually slow your acquisition speed), but
it can be a lifesaver if you need to sample over long periods -- especially
if the computer must be left unattended.
To turn on automatic file saving, you need to specify
the 'backup interval" between saves. Obviously, the shorter the
interval, the greater the protection. However, it takes some time
to save data (not much if you are saving in binary format), and at high
sample rates this can slow acquisition. The LabHelper default
is to use a saving interval equal to 50% of the expected acquisition period
(i.e., the sample interval times the maximum number of samples), or 30 minutes,
whichever is smaller. You can use the window shown at right to specify
any backup interval, or to switch off automatic backup.
If automatic file saving is operating, a gray menu ("backup ON") appears, and as backups occur this menu is incremented (i.e., "backup 1", then "backup 2", etc.). The data are saved in the current folder. They are named "backup file" and (optionally) have the current date appended (i.e., "backup file 10/10/98"). Sequential backups saved on the same day will overwrite each other, but if the date is appended a new backup name will be used when the date changes at midnight.
If acquisition concludes normally, you can save the complete set of data under any name you wish, and the backup file(s) can be disposed of.
GET PREFERENCES Allows loading of a preferences file
containing general parameters such as default screen colors and user-specified
voltage conversions. This is not the same as a setup file,
which contains specific channel, screen format, and external device information.
By creating a number of different preference files, you can set up a variety
of clickable voltage conversions or default screen colors. Note that
the program automatically loads a file called 'LabHelper prefs' when
launched.
SAVE PREFERENCES Stores the current acquisition values (colors,
conversions, etc.) in a preferences file. If you use the filename
'LabHelper prefs' and save it in the folder containing LabHelper,
your selections are automatically loaded at startup.
QUIT exits the program.
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 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..
SAMPLE RATE 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%.
USE MONOCHROME Toggles between color and monochrome display.
This may not have a visible effect until a new window is opened. Note:
if you use a monochrome monitor, LabHelper should automatically
shift into this mode when launched.
SCREEN COLORS Lets you select colors for chart and oscilloscope
screens from the standard Mac color wheel. Obviously, this option
is not available on monochrome monitors. Color preferences can be
saved for automatic re-use the next time the program is launched (use the
SAVE PREFERENCES menu selection). This option is deselected
unless color is in use.
SHOW TIME GRID Activates or deactivates the display of time
grids and tics in plot areas during data acquisition.
DASHED MARKER LINES Toggles between normal (dashed) and solid
marker lines in plot areas. During chart file acquisition, markers
appear when individual keys are pressed.
SCREEN SIZE On a large screen, this option allows use of several
window sizes (from 640 X 400 pixels up to the maximum screen size).
LabHelper windows are always located in the upper left corner of
the screen and cannot (or should not) be dragged.
STATUS DISPLAYS At moderate sampling rates, LabHelper
provides several status displays on the data acquisition screen. These
include the 'data bar' at the top of the screen (showing sample number,
percent completion, time-to-go, etc.), a numeric readout in each
channel, and alarm or device switching status (if selected
by the user). Unfortunately, it takes time to update these displays,
which can slow data acquisition at very high sampling rates. Switching
off the status displays will speed up acquisition, particularly at the fastest
sample rates. Since both updating and sampling speeds are highly
dependent on the speed of the particular CPU and screen, it is something
of a trial and error process to find sampling rates that are compatible
with status displays.
Use this window to adjust the 'cutoff' sampling rate above which status displays are switched off (you can also instruct LabHelper to leave them on or off at all speeds).
SHOW SWITCH STATUS Activates or deactivates a display of the
external device control status during data acquisition. This shows
whether a particular channel's device is acquiring sample data, reference
data, or is inactivated (zeroed).
In addition to the graphical display, LabHelper shows digital
readouts of channel values during data acquisition. The LARGE READOUTS
option toggles between the normal size digital readout displays (in 10-point
type) and a much larger display (in 20-point boldface) that is more easily
visible from a distance.
SLOPE TRENDS Opens a window containing controls for the display
of recent trends in the data (positive or negative slope) for any channel:
The number of points used to generate the slope trend is user-selectable; the default value is 5. Slope trends are shown as a "+" or "-" indicator in the digital display for each channel selected. NOTE: slope trends is only available in CHART mode, and it does not store in a 'Setup' file.
CONVERSION EQUATIONS This selection has a submenu that allows
you to change the voltage conversion and labeling from the regular voltage conversion window, instead of editing
a series of values in different edit fields. NOTE: oscilloscope channels
are not accessible to such manipulations, since they record raw voltages
only.
The next few selections allow the user to override the automatic selection of an internal A to D converter (Lab-NB, PCI-1200, or DAQCard-1200) if necessary.
Use this entire menu very cautiously, as a system crash or lockup may result if you tell the program to use a nonexistent device or an incorrect port or baud rate with an external A-D device. |
USE DIGITAL PORT 0 and USE DIGITAL PORT 2 These items
specify which of the digital output ports on a National Instruments card
is used to control external devices. NI cards have 3 digital ports;
2 is the default and 1 is not available.
USE ADC-1 Switch to using an external Remote Measurement Systems
ADC-1 A-D device.
USE DATATAKER Switch to using an external Data Electronics DataTaker
A-D device.
DATATAKER A-D STATUS Allows use of the DataTaker's ability to
return temperatures (instead of microvoltages) from thermocouples (note
that the default setting is for copper-constantan thermocouples).
It also allows selection of differential or single-ended inputs for voltage
measurements, or use of the high-speed counter:
In this example, there are 10 channels in use. One of them (#9) uses the high speed counter, which starts counting with a value of zero. Three channels (#1, #4, and #5) use copper-constantan thermocouples. The remaining channels read voltages; two are connected as single-ended inputs and three as differential inputs.
CONFIGURE SERIAL PORT...' This option lets you may override
the default serial port and baud rate if using an external A-D device.
Make sure you set the same baud rate on both the computer and the external
A-D device. Note that LabHelper assumes that any external A-D
device (ADC-1 or DataTaker) is set to run with no parity, 8 data bits, and
2 stop bits. If you chose to change the serial port, make this selection
immediately after launching the program. DO NOT switch between
printer and modem ports during a run, as this will probably crash the program
(maybe even the computer).
TEST MODE (DEMO) This option uses a random number generator
to allow program setup and experimentation without connection to an actual
analog-to-digital converter.
The set alarms selection opens a window (shown in the following
example) that allows you to set up the alarm status for each channel.
An alarm is triggered whenever the input to that channel violates certain
conditions -- some fixed, some user-specified. If alarms are set,
warnings of alarm conditions appear in the upper right corner of chart output
during data gathering. Optionally, an audible buzzer can be triggered
by an alarm condition. Finally, a summary of alarms can be called
up from the Options window at the end
of a data run. Note that alarms do not function with oscilloscope
channels.
Three types of alarms are possible:
Note that using alarms can slow the maximum possible sampling rate. However, for most sampling rates, use of alarms has no effect on performance.
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