Hi,
You program to the requirements of your RS-485 converter (different
manufacturers use slightly different techniques) AND, more importantly, you
musty implement the software protocol that your connected device uses.
There is no standard protocol used for all such devices, though there are
defacto standards used for certain kinds of devices. You need the
documentation provided by the manufacturer of your specific device to
determine how to code the packets of data that are sent and to decode the
data received.
For the actual serial control you can download DesktopSerialIO dll from my
homepage, which gives you full control of CTS and RTS (which you may or may
not need, depending on the RS-485 converter), and you can use it to send and
receive the serial data. There are other serial classes available online,
too.
I have more detailed information on RS-485 in my book, and there is an
online tutorial on
www.bb-elec.com that you may find to be useful.
Dick
--
Richard Grier (Microsoft Visual Basic MVP)
See
www.hardandsoftware.net for contact information.
Author of Visual Basic Programmer's Guide to Serial Communications, 4th
Edition ISBN 1-890422-28-2 (391 pages) published July 2004. See
www.mabry.com/vbpgser4 to order.
