sepam 20 user manual - Schneider Electric

7
PE80120
Use SFT2841 setting and operating
software
Configuration of a Sepam network
Configuration window for the communication network via
telephone modem.
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Configuration of called modem
The modem on the Sepam side is the called modem. It must first be configured,
either via AT commands from a PC using HyperTerminal or the configuration tool that
may have been supplied with the modem, or by setting switches (see the modem
manufacturer’s manual).
Modem RS 485 interface
In general, the configuration parameters for the modem’s RS 485 interface must be
defined in accordance with the Sepam communication interface configuration:
b speed: 4800, 9600, 19200 or 38400 bauds
b character format: 8 data bits + 1 stop bit + parity (none, even, odd).
Telephone network interface
Modern modems offer sophisticated features such as checking the quality of the
telephone line, error correction and data compression. These options are not
appropriate for communication between SFT2841 and Sepam, which is based on the
Modbus RTU protocol. Their effect on communication performance may be the
opposite of the expected result.
It is therefore highly advisable to:
b Invalidate the error correction, data compression and telephone line quality
monitoring options
b Use the same end-to-end communication speed between:
v the Sepam network and the called modem
v the called modem (Sepam side) and the calling modem (PC side)
v the PC and the calling modem (see recommended configurations table).
Sepam network Telephone network PC modem interface
38400 bauds V34 modulation, 33600 bauds 38400 bauds
19200 bauds V34 modulation, 19200 bauds 19200 bauds
9600 bauds V32 modulation, 9600 bauds 9600 bauds
Industrial configuration profile
The following table shows the main characteristics of the modem on the Sepam side.
These characteristics match a configuration profile commonly known as an
"industrial profile", as opposed to the configuration of modems used in offices.
Depending on the type of modem used, the configuration will either be via AT
commands from a PC using HyperTerminal or the configuration tool that may have
been supplied with the modem, or by setting switches (see the modem
manufacturer’s manual).
Characteristics of the "industrial profile" configuration AT command
Transmission in buffered mode, without error correction \N0 (force &Q6)
Data compression deactivated %C0
Line quality monitoring deactivated %E0
DTR signal assumed to be permanently off (allows the modem
connection to be established automatically on an incoming call)
&D0
CD signal off when carrier is present &C1
All reports made to Sepam blocked Q1
Character echo suppression E0
No flow control &K0
PCRED301005EN - 06/2008