Installation manual

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4
4.4
X-Way and the OSI model
(continued)
Modicon TSX Micro
automation platform 0
X-way communication
The services provided depend on the type of device (PLC, numerical controller,
programming terminal, supervision station, etc.). Depending on its function, each
device can be Client and/or Server.
A Client PLC can access other devices on the
architecture via its application program: It can read/write objects on another PLC or
numerical controller, select programs on a numerical controller, etc.
When connected to any station in the network or directly connected to the Fipway/
Ethernet TCP/IP 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 dialoguing).
Network transparency also applies between stations connected to different
segments of the same multinetwork architecture.
The COM service is made up of a set of dedicated words called common words.
Each Fipway/Ethway network station may or may not access the 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 the Fipway network, and variable from 4 to
64 words for the Ethway network) 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 TSX Micro/Premium PLCs which comprise
the Fipway network. The exchange principle is based on the 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.
This consists of using the user application program to send word tables between
2 devices, which may be TSX Micro/Premium and TSX 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 transmission and destination device.
b Sending broadcast messages to all stations and devices.
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 TSX Micro/Premium PLC is sent immediately without waiting for
the end of the cycle. The telegram is received by the 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).
b A PLC can only process one telegram at a time.
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 could be transferred to the
valid network.
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.
Network transparency
COM service and Shared Table service (exclusive services one from another)
Application-to-application communication
Telegram
Use in a multinetwork
Courtesy of Steven Engineering, Inc. ● 230 Ryan Way, South San Francisco, CA 94080-6370 ● General Inquiries: [phone] ● www.stevenengineering.com
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