User manual

IEC61131 User and Reference Manual
April 22, 2008
580
Duplex
The TeleBUS DF1 protocols communicate in one direction at a time. However the duplex
setting is determined by the type of serial data link used. The table below shows the possible
settings for the controller. Note that not all port types are available on all controllers.
Port Type
Possible
Settings
Recommended Setting
RS-232 or
RS-232
Dial-up
modem
half duplex
full duplex
Use full duplex wherever
possible.
Use half duplex for most
external modems.
RS-485
half duplex
full duplex
Slave stations always use
half duplex.
Master stations can use full
duplex only on 4 wire
systems.
Protocol Parameters
The TeleBUS DF1 protocols operate independently on each serial port. Each port may set
the protocol type, station number, protocol task priority and store-and-forward messaging
options.
The protocol configuration can be set in four ways:
 using the TelePACE or ISaGRAF programs;
 using the set_protocol function from a C application program;
 writing to the I/O database from a C or ladder logic application program; or
 writing to the I/O database remotely from a Modbus or DF1 compatible device.
To configure protocol settings through the I/O database, add the module, CNFG Protocol
settings, to the Register Assignment.