3 UNI-TELWAY protocol. Schneider Electric XGKS... / XGPS... Communication card, UNI-TELWAY and Modbus / Jbus protocols

3 UNI-TELWAY protocol

I

S

H

E

N

G

L

3.1

General

This section gives a brief summary of UNI-TELWAY requests. Please refer to the

XG field station "User’s Manual" for more details.

The exchange of data between computer systems, PLCs and other intelligent systems must be performed using a common language.

This language must be as simple as possible and understood by everyone involved. It must also be possible to check each exchange to ensure the integrity of the transfers.

The variables exchanged are inserted in a frame which is usually made up in the following way :

Header Address Request Data Check

Each protocol defines the presence, the format and the content of the various groups of variables which surround the data zone.

This structuring makes it possible to define the start of messages, their size, if necessary the system to which the data is addressed, the type of function requested, the variables themselves, a check parameter and an end code which validates the whole message.

The form and content of this frame are different for each type of protocol.

3.2

UNI-TELWAY frames

Header

Destination address

Sender address

Length of message

Category

& request

Data Check

10

3 UNI-TELWAY protocol

3.3

List of requests

The following table lists the requests accepted by the XG field station, and their limits :

Request

Protocol version

Mirror

Read error counters

Reset counters

Read a word (*)

Write a word (*)

Read objects (*)

Write objects (*)

Code

16#30

16#FA

16#A2

16#A4

16#04

16#14

16#36

16#37

(*) : Immediate execution : There is no wait for a tag.

XG field station

Yes

Yes

Yes

Yes

Yes

Yes

64 words max

60 words max

I

S

H

E

N

G

L

11