General
Software compatibility
X-WAY transparency
Transmission l l
The modem card provides X-WAY transparency, and supports two types of protocol:
Uni-telway master or slave protocol, character mode protocol.
When a local network station communicates with a remote station on the switched telephone network, the calling station must be in master mode, and the called station in slave mode.
The speed of transmission varies between 4800 bits/s and 9600 bits/s. The size of the frames sent is 256 bytes in total (240 bytes usable in Uni-telway mode, and 200 bytes in character mode).
Only one communication function can be active at a time on the TSX MDM 10 card.
The application must manage line disconnection. Only the station which initiated connection using External CALL_MODEM (See External CALL_MODEM function,
p. 71) has the right to disconnect the line.
The CALL_MODEM communication function ensures disconnection.
The TSX MDM 10 card defines a set operation for the INPUT_CHAR instruction.
When the INPUT_CHAR function is activated, the frame end character must be received before the end of the task cycle.
If several cycles are needed to receive this character, the character string is lost.
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General
The application Modem configuration requires PL7 software from version V3.3 onwards.
CAUTION
Downloading the application
The modem card cannot be used to up- or download a PL7 application.
If loading is initiated by mistake, a failure message will appear on connection and the PLC application will be lost.
However, it is always possible to load an application via the terminal port.
Failure to observe this precaution can result in injury or equipment damage.
The station called can recognize a maximum of 8 calling stations for TSX Micro
PLCs, and 16 for TSX Premium PLCs where the password service is used. Only the
TSX MDM 10 card ensures the management of passwords. For third party devices, passwords are managed according to the coding protocol for password exchanges.
See
Coding of exchanges, p. 104.
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