DIGITAL INPUT/OUTPUT CARD IOD-144 USER MANUAL
5-3
Note that in all of the above functions, an inherent limitation of BASIC in general and
VisualBASIC in particular makes the values sent less intuitive. All integers in BASIC are
signed numbers, wherein data are stored in two's complement form. All bit patterns must
be converted to-and-from this two's complement form if meaningful display is required.
Otherwise, values returned from the InPortb function will be -128 to 127, rather than 0 to
255. An alternative is to perform all assignments in hexadecimal, rather then decimal form.
Before the program will execute, the .GBL file must be modified to include the path to the
VBACCES.DLL as appropriate for your system. Merely replace the statement "-
VBACCES.DLL" with "drive:path\VBACCES.DLL".
As an alternative to changing the source code, you can copy the VBACCES.DLL file into
your Windows directory. This will allow multiple programs to find the same .DLL without
having to know where it is located. Just leave off all references to a path in the .GBL file
as shown in the sample.