NIM Primitives
4-2
TIWAY 1 TI505 NIM User Manual
4.2
PURPOSE
Primitives serve as the command structure that a TIWAY I Primary uses to access (read
or write) information in a TIWAY I Secondary. The Primitives defined in the following
paragraphs serve these basic functional needs.
Access and retrieve data
Ascertain the status and configuration of attached devices
Perform control operations on the attached device
4.3
STRUCTURE AND OPERATION
A Primitive consists of multiple fields that specify the Primitive’s length and function,
type and location of data to be accessed, and data to be transferred. In TIWAY I, a Primi-
tive forms the information field of an HDLC Information frame (I) or Unnumbered Infor-
mation frame (UI) if HDLC operation is selected. If X.25 operation is selected, the Primi-
tive is contained in the User Data field of an X.25 Data Packet.
WARNING
When you write to memory, you may be directly affecting the
process which is under control by the programmable controller.
Before you make changes in memory, be certain that the
changes which result in the controlled process will not endan-
ger any personnel or equipment.
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