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Network variables – Echelon IzoT NodeBuilder User Manual

Page 25

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Field

Description

• Standard manufacturer IDs are assigned to manufacturers when they

join L

ON

M

ARK

International, and are also published by L

ON

M

ARK

International so that the device manufacturer of a L

ON

M

ARK

certified

device is easily identified. Standard manufacturer IDs are never
reused or reassigned. If your company is a L

ON

M

ARK

member, but

you do not know your manufacturer ID, you can find your ID in the
list of manufacturer IDs at

www.lonmark.org/spid

. The most current

list at the time of release of the NodeBuilder tool is also included with
the IzoT NodeBuilder software.

• Temporary manufacturer IDs are available at no charge to anyone on

request by filling out a simple form at

www.lonmark.org/mid

.

Device Class (C)

A 4 hex-digit value identifying the primary function of the device. This
value is drawn from a registry of pre-defined device class definitions. If
an appropriate device class designation is not available, the L

ON

M

ARK

International Secretary will assign one, upon request.

Usage (U)

A 2 hex-digit value identifying the intended usage of the device. The
upper bit specifies whether the device has a changeable interface. The
next bit specifies whether the remainder of the usage field specifies a
standard usage or a functional-profile specific usage. The standard usage
values are drawn from a registry of pre-defined usage definitions. If an
appropriate usage designation is not available one will be assigned upon
request. If the second bit is set, a custom set of usage values is specified
by the primary functional profile for the device.

Channel Type (T)

A 2 hex-digit value identifying the channel type supported by the device’s
transceiver. The standard channel-type values are drawn from a registry
of pre-defined channel-type definitions. A custom channel-type is
available for channel types not listed in the standard registry.

Model Number (N)

A 2 hex-digit value identifying the specific product model. Model
numbers are assigned by the product manufacturer and must be unique
within the device class, usage, and channel type for the manufacturer. The
same hardware may be used for multiple model numbers depending on the
program that is loaded into the hardware. The model number within the
program ID does not have to conform to your published model number.

See the LonMark Application Layer Interoperability Guidelines for more
information about program IDs.

Network Variables

Applications exchange information with other L

ON

W

ORKS

devices using network variables. Every

network variable has a direction, type, and length. The network variable direction can be either input
or output, depending on whether the network variable is used to receive or send data. The network
variable type determines the format of the data.

Network variables of identical type and length but opposite directions can be connected to allow the
devices to share information. For example, an application on a lighting device could have an input
network variable that was of the switch type, while an application on a dimmer-switch device could
have an output network variable of the same type. A network management tool such as the IzoT
Commissioning Tool could be used to connect these two devices, allowing the switch to control the
lighting device, as shown in the following figure:

IzoT NodeBuilder User's Guide

11