IDEC SX5L Series - Manual (Page 7)

1: G ENERAL I NFORMATION
1-2 SX5L C OMMUNICATION T ERMINAL U SER ’ S M ANUAL
L ON W ORKS Device and Functional Block
The following figure illustrates examples of L ON W ORKS devices. Device A consists of switches to send the ON/OFF status
signals of three switches to the network when they are operated. Device B consists of two lamps which go on or off when
receiving ON/OFF signals from the network.
The intended operation programmed in the L ON W ORKS device is represented by a functional block. The interface with the
network to send the operation results and receive commands is the network variable.
In the next figure, the operation performed by device A is represented by functional block A, which contains three network
variables to send the statuses of three switches. The operation performed by device B is represented by functional block B,
which has two network variables to receive commands to turn on and off the lamps. Network variables to send data are
called output network variables, and those to receive data are input network variables.
When network variable D is designated as the destination of network variable A, it is made possible for the device A
switches to turn on or off the device B lamps. This procedure is called binding.
Standard Network Variable Type and Standard Configuration Property Type
As shown in the figure of the example of L ON W ORKS Network on the preceding page, the L ON W ORKS network can deal
with various types of data in addition to ON/OFF statuses, such as angle, temperature, illuminance, voltage, and current.
Unlike other field-level networks which transmit data without physical units, L
ON W ORKS can send data with physical
units. The L ON M ARK Interoperability Association defines Standard Network Variable Types (SNVTs) to facilitate interop-
erability by providing a well-defined interface for communication between devices made by different manufacturers. The
association also defines Standard Configuration Property Types (SCPTs) to further facilitate interoperability by providing
a well-defined compact mechanism for handling large amounts of configuration information on a device
Address and Table
The LonTalk protocol usually uses a combination of domain ID, subnet ID, and node ID to identify the address of the
receiving device. Each L
ON W ORKS device has a domain table to store its address (source address) and an address table to
store the addresses to send data to (destination addresses). All SX5L communication terminals can store 2 addresses in the
domain table and 15 addresses in the address table, or the maximum quantities allowed for a L
ON W ORKS device.
To identify each network variable contained in a L ON W ORKS device, each network variable is assigned an address called
selector address. Mutually bound network variables are assigned the same selector address. When the value of a network
variable is sent to multiple network variables, the network variable of the transmitting device sometimes require another
Neuron
Chip
Neuron
Chip
Device A Device B
Example of L ON W ORKS Devices
Functional Block A
Example of Functional Blocks
Network Variable A
Functional Block B
Network Variable C
Network Variable B
Network Variable E
Network Variable D