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

CHAPTER 4: USING THE IEEE 1394-BASED PROTOCOL
If you want to save the response data—or if you want to calculate offset and gain by hand—you
can write this data to the memory map area “Analog and Digital Point Configuration
Information—Read/Write” on page 125.
Configuring I/O Points, Event/Reactions, and
Security
See Chapter 2 for important information on configuring I/O points, I/O point features,
event/reactions, and other system functions.
Reading Module Types
Analog/digital/serial brains can recognize analog and serial modules on the rack and report what
they are. All SNAP Ethernet-based brains report digital modules and empty slots the same,
however.
To read a module type, use the “Analog and Digital Point Configuration
Information—Read/Write” area of the memory map. (See page 125.) Module type values are
shown in the table on page 18.
Configuring I/O Point Types
Although analog/digital/serial brains recognizes module types for analog modules, they do not
recognize digital modules or individual analog point values. If the actual module type or point
values differ from the defaults, you must assign the correct values by writing to the “Analog and
Digital Point Configuration Information—Read/Write” area of the memory map. (See page 125.)
Point type values are shown in the table starting on page 19.
Configuring I/O Point Features
For counters and quadrature counters, you must also configure the I/O point feature. See
page 88.
92 SNAP Ethernet-Based I/O Units Protocols and Programming Guide