snap ethernet-based i/o units protocols and programming guide

Appendix B
Table of Offsets
Introduction
Table
APPENDIX B
If you are using the SNAP Ethernet-based brain’s memory map, the table on the following pages
can help you find addresses more easily. Addresses for successive points in the memory map are
often offset by 40 hex or by 4 hex, depending on the data space needed for that area of the map.
For example, in the area “Digital Point Read—Read Only” on page 121, each successive point
begins on an even 40 hex boundary. Points 0, 1, and 2 are shown for you, but what if you need to
read point 28? Using the table in this appendix, read down the Point (Decimal) column to find
point 28, then read across to the Offset 40 Hex column, where you’ll see the beginning address
for point 28: 0700. Following the pattern established on page 121, you can see that the Digital
Point Read addresses for point 28 are:
FFFF F080 0700 4 Point 28: Point state (Boolean)
FFFF F080 0704 4 Point 28: On-latch state (Boolean)
FFFF F080 0708 4 Point 28: Off-latch state (Boolean)
FFFF F080 070C 4 Point 28: Active counter (Boolean)
FFFF F080 0710 4 Point 28: Counter data (unsigned integer)
Module Point (Decimal) Point (Hex) Offset 40 Hex Offset 4 Hex
0 00 00 0000 0000
0 01 01 0040 0004
0 02 02 0080 0008
0 03 03 00C0 000C
1 04 04 0100 0010
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