Constantattribute – Echelon OpenLNS User Manual
Page 195
OpenLNS Programmer's Reference
158
by an array of network variables, the array elements will be
implemented by consecutive network variables. This
property returns the network variable index of the first
element. To determine the network variable index for
subsequent elements, simply increment this network variable
index the appropriate number of times.
Note: This property is not currently available from within a
DeviceTemplate object; therefore, it will throw a
LCA, #38
LCA_APP_DEVICE_REQUIRED
exception when accessed.
Availability
Local, full, and lightweight clients.
Syntax
nvIndex = cpObject.ConfigNvIndex
Element
Description
nvIndex
The index of the configuration
network variable implementing this
configuration property.
cpObject
The network variable-based
Data Type
Short.
Read/Write
Read only.
Added to API
OpenLNS.
ConstantAttribute
Summary
Reads or writes the constant attribute of the configuration
property.
Many configuration properties contain a constant attribute,
which indicates that the value of the configuration property
should not be changed by a network management tool such
as an OpenLNS application. You can use this property to set
or turn off the constant attribute of a configuration property.
Generally, configuration properties with the constant
attribute set should not be modified by OpenLNS
applications, or by any other means. However, version LNS
Release 3.20 of the LonMark Application-Layer
Interoperability Guidelines LNS Release 3.20 introduced
constant, device-specific configuration properties, which can
be modified by the device, but not by a network management
tool. Modifiable device-specific configuration properties were
introduced in version 3.4 of the LonMark Application-Layer
Interoperability Guidelines. These device-specific
configuration properties can be modified by the device, and
by a network management tool.
In the interim, many LonMark devices were defined with
constant, device-specific configuration properties. Some of
these configuration properties would more naturally have
been defined as modifiable, device-specific configuration
properties, if these had been defined by the LonMark