Technologies Computer Driver Instruction Manual

FS-8700-41 Simplex 4100 Driver Manual Page 43 of 58
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Appendix B.3. Resolving Network Addresses above 255
The Standard format for addressing a simplex point is c-p-s (Card-Point-Subpoint). Each of
these components in the address supports a maximum value of 255. However, when using
an NDU (Network Display Unit), addresses may be supplied in a Card-Address format
where the address value could be substantially larger than 255. In these applications it will
be necessary to convert the Card-Address format into c-p-s format before configuring the
points in the FieldServer.
The formula used to convert between the two formats is as follows:
Card is the same for both formats.
Network Address = ((Point-1)*256) + Sub-Point + 1
This conversion procedure is best illustrated by means of an example:
Example:
Card–Address point supplied = 5-2936
From this we deduce the card number to be 5. The next step is to break the address into
multiples of 256 in order to determine point and sub-point. Since this is also a hex
denominated calculation, an easy way to do this is to convert the value to Hex:
2936 = 0xB78
Now, break out the last two hex numbers for sub-point portion, and use the rest for point
address. So we get:
0xB = 11 = (Point-1)
0x78 = 120 = Sub-Point + 1
Solving this equation, we get:
Point = 12
Sub-Point = 119