Rockwell Automation 2LW3000 LonWorks Communication Option Module for VTAC 7 Drives - Manual (Page 53)

Operating the Drive Using a LonMark Profile 7-1
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HAPTER
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Operating the Drive
Using a LonMark Profile
A LonMark profile defines the functional profile for a node communicating with other
nodes. The profile specifies which SNVTs (Standard Network Variable Types) and
SCPTs (Standard Configuration Property Types) are used, and provides a semantic
meaning about the information being communicated.
When a profile is implemented in a node, it’s called a LonMark object. One node can
have several objects implemented. The LonWorks module has two objects: a node
object and a drive object. The node object is used to control the other objects in a
node. See figure 7.1
The drive object is based on a specific LonMark functional profile, as shown in figure
7.2.
Data exchange on a LonWorks network is handled with Standard Network Variable
Types (SNVTs), which represent different types of standard data (e.g., temperature,
pressure, voltage). The LonWorks module contains a fixed setup of SNVTs, and each
SNVT is mapped to a VTAC 7 drive parameter.
A network variable is any data item (such as temperature or a switch value) that a
particular device application program expects to receive from other devices on the
network (called an input network variable or NVI) or expects to make available to other
devices on the network (called an output network variable or NVO).
When a program writes into one of its output network variables, the new value of the
network variable is propagated across the network to all nodes with input network
variables connected to that output network variable.
Specific network variables are described in sections 7.1 through 7.3.
Figure 7.1 – Node Object
Node Object
Mandatory
Network
Variables
nv1
nviRequest
SNVT_obj_request
nv2
nvoStatus
SNVT_obj_status