233 / 413
5/99
X-Way and the OSI model
(
continued)
Modicon Premium automation
platform
0
X-Way communication
X-Way and the OSI model
(
continued)
Uni-TE services
(
continued)
The services provided depend on the type of device (PLC, programming terminal,
supervision station, etc.). Depending on its function, each device can be Client and/
or Server. AClient PLC can access other devices in the architecture via its
application program: it can read/write objects on another PLC or numerical
controller, select programs on a numerical controller, etc.
Network transparency
When connected to any station in the network or directly connected to the Fipway/
Ethernet Modbus/TCP network, a programming terminal can communicate with any
other station in the network (as if the terminal were physically connected to the PLC
with which it is communicating).
Network transparency also applies between stations connected to different
segments of the same multinetwork architecture.
COM service and Shared Table service
(
mutually exclusive services)
The COM service
is made up of a set of dedicated words called common words.
Each Fipway/Ethway network station may or may not be able to access this
database (in read only or read/write mode).
All PLC stations exchanging common words (32 stations on Fipway, 64 stations on
Ethway) are allocated, in a dedicated database (128 words for Fipway, 256 words for
Ethway), a write zone (set at 4 words for Fipway, and variable from 4 to 64 words for
Ethway ) per TSX Micro/Premium station.
COM words are updated automatically during each scan of the general sequential
program (master task) without the intervention of the application program.
The Shared Table service
can be used to exchange a table of internal words
divided into as many zones as there are Modicon TSX Micro/Premium PLCs
comprising the Fipway network. The exchange principle is based on broadcasting,
by each PLC, of a word memory zone (broadcast zone) to the other PLCs on the
network.
Each network station is allocated an exchange table comprising 128 internal words
for the 32 PLCs that share the service, with a broadcast zone assigned to each PLC,
variable from 1 to 32 internal words.
Application-to-application communication
The user application program sends word tables between 2 devices, which may be
Modicon TSX Micro/Premium PLCs.
This service is particularly suitable for:
b
Sending alarm messages from a PLC to a supervision station.
b
Exchanging data tables between two PLCs controlled by the application programs
of the sender and recipient.
b
Sending broadcast messages to all stations and devices.
Telegram
The telegram service available on Fipway is a special case of application-to-application
messages. It enables short messages to be sent and received on a priority basis
(
maximum 16 characters).
A telegram from a Modicon TSX Micro/Premium PLC is sent immediately without
waiting for the end of the cycle. The telegram is received by the Modicon TSX
Micro/Premium PLC in:
b
The event-triggered task (processed as soon as the message arrives in the
network card).
b
The fast task or master task (when scanning the reception function).
A PLC can only process one telegram at a time.
Use in a multinetwork
The X-Way communication architecture is designed to cover multinetwork
applications capable of dealing with problems of:
b
Concentration: The architecture is particularly suitable for feedback of supervision
data to a higher level.
b
Redundancy: Each PLC monitors the correct operation of both networks to which
it is connected. If one of the networks should fail, all traffic can be transferred to the
network that is functioning.
b
Inter-network communication: These architectures comprise several network
segments which are interconnected by “bridge PLC” stations. Transparent
communication is then offered between the entire architecture.
2
1
3
4
5
6
7
8
9
10