LabHelper X interfaces with external serial A-D converters and offers the option of using the Sable Systems Universal Interface UI2, Remote Measurement Systems ADC-1, or some of the Data Electronics DataTakers.  NOTE: use of the ADC-1 or DataTaker does not permit high sampling rates, and older laptops do not easily interface with serial devices.

• The Sable UI2 has 8 channels of 16-bit A-D conversion (plus or minus 5 volt range) and 4 channels for temperature inputs using special thermistors; these can also be used for voltage inputs (0-5 volts), or current, or resistance measures. The UI2 has 8 digital outputs that can switch external devices, and two analog voltage outputs.  LabHelper X sets the UI2 to run at 115,200 baud for fast communications.   A USB to serial converter is necessary to use the UI2 or any serial device; the Keyspan units work well; some others do not (for unknown reasons).
          PLEASE NOTE: the new UI3 (with a USB connection) is not supported by LabHelper X.

• The ADC-1 (now long discontinued) has 16 input channels, and most versions have a 50X programmable gain option on a ±0.42 volt input range.  The ADC-1 also has 6 output channels that can be used to switch external devices.   It's very slow, but these old units are still useful for some purposes.

• DataTakers (several models) are quite sophisticated (but slower than the UI2).   They have a variable number of analog input channels, depending on which model is used and whether any extension modules are attached.  They can also read thermocouples directly (i.e., they return a temperature instead of the microvoltage potential).  Several digital outputs to switch external devices are also available (depending on model).  As for the UI2, a USB to serial converter is required to communicate with a DataTaker; the Keyspan units work well; some others do not, for unknown reasons.   Wiring of the cable between the computer and the DataTaker is more complex than with the UI-2 (but is clearly described in the DataTaker manual).
  

A simulated A-D converter is used in the Test Mode option.  No A-D hardware is needed to explore the software.

LabHelper X stores data in a floating-point format with a precision of roughly 8 decimal digits.  This saves considerable disk and memory space compared to storage at higher precisions, but provides somewhat lower numeric resolution.  For example, in 8-digit precision (but not 10-digit precision) the numbers 12445.239 and 12445.23914 are 'identical'.  This minor limitation should pose few problems to the average user, especially because the accuracy of most data is considerably less than can be represented in even 6 decimal digits.  A 16-bit analog-to-digital converter working optimally can resolve one part in 65,535, for example -- five decimal digits. 

LabHelper X was written in FutureBasic and FBtoC by Mark Chappell (a.k.a.  'Warthog Systems', with apologies to Gilbert Shelton) with facilities provided by the University of California, Riverside.   No warranty of any kind is offered or implied.  LabHelper X is NOT a commercial product and may not be sold or copied for commercial purposes.  If you have questions you may contact me at the Biology Department, U.C.  Riverside, Riverside, CA 92521.  My email address is: chappell@ucr.edu