4-10
Industio
CI-134 Series User’s Manual
RS-485 Programming
If you intend to do RS-485 communication with
Industio
CI-134 Series, please follow
the RS-485 programming guide below and also refer to the chapter, “
Connection
Cable and Cable Wir ing”
, for more RS-485 operation details.
The
Industio
CI-134 Series supports
only 2-wir e half-duplex RS-485
communication
.
Data+/-
pins are served for both data transmitting and receiving,
depending on the mode selected: either Automatic Data Direction Control or By RTS
mode.
Automatic Data Direction Control Mode (Recommended)
Automatic Data Dir ection Contr ol
scheme is the best solutions for RS-485
applications. The mode switch for the port should be set to
ON
position, to be able to
use Automatic Data Direction Control Mode.
Under this mode, no extra code is required to control the data transferring (data
transmitting and receiving), which is automatically managed with the intelligent
hardware mechanism. That is,
RS-485 pr ogr amming in this mode is just as simple
as RS-232/RS-422 pr ogr amming
.
By RTS Mode (For back-compatibility)
If the mode switch for the port is set to
OFF
position, By RTS Mode is used. The port
is ready for transmitting data if
RTS signal is asser ted
and ready for receiving data
if
RTS signal is not asser ted
.
RTS
scheme is a traditional way and suitable for most system, including Windows
NT, Windows 95/98 and DOS, or even UNIX, that permits RTS control from
application programs. This mode should be compatible with most of the already-
made RS-485 applications.
How to transmit and receive data for Windows NT, 95/98 & DOS
We recommend you to configure
Industio
CI-134 Series ports as follows in order to
acquire precise timing control in RS-485 2-wire transmission.
