National Instruments 3.22E+04 Manual De Usuario

© National Instruments Corporation

This chapter describes how to set the hardware transceiver control mode for 
your RS-485 interfaces and lists some general programming requirements.

The NI-Serial software is fully integrated into the standard Windows Me/9x 
communications software. NI serial ports are used like any other 
Windows Me/9x communications (COM) port. Windows Me/9x has 
standard communication functions for use within either Win16 or 
Win32 applications.

When you develop your application, remember that you must use 
the standard Microsoft Windows serial communication functions. For 
information about Microsoft Windows serial communication functions, 
refer to the Win32 Software Development Kit and to the Win32 Overviews 
and Win32 Reference online help.

If you have LabVIEW or LabWindows/CVI and want to use it with your 
serial hardware, refer to your LabVIEW or LabWindows/CVI 
documentation for information about serial I/O functions.

Transceiver modes apply only to the PCI-485 boards.

The PCI-485 boards support four modes of hardware transceiver control. 
You can use hardware flow control to enable and disable your transmitters 
and receivers so that they function on different bus topologies. Table 4-1 
lists the status of the transmitters and receivers under each of the 
transceiver control modes.