National Instruments PCI-8430, Manual

Page: 105 / 237

Modifying the RS-485 Transceiver Mode Programmatically
To modify the RS-485 transceiver mode programmatically:
Change the NI-VISA wire mode attribute.
The NI-Serial software uses programmatic control codes and the
DeviceIoControl Windows function for programming the RS-485
transceiver control mode.
Setting the RS-485 Transceiver Control Mode on PCI, PXI,
USB, ExpressCard, and PCMCIA Hardware
To set and retrieve the RS-485 transceiver control mode using the
DeviceIoControl Windows function on PCI, PXI, USB,
ExpressCard, and PCMCIA RS-485 hardware, complete the
following steps:
1. Add the following lines to your source code:
#include <winioctl.h>
#include <NiSerial.h>
Note You can find the header file
NiSerial.h
in the
NI-
Serial
folder where you installed your National
Instruments software (typically,
C:\Program
Files\National Instruments\NI-Serial ). It is also included
on your NI-Serial software CD.
2. The
TRANSCEIVER_MODE
attribute can have the following
values:
RS485_MODE_4WIRE
RS485_MODE_2W_ECHO
RS485_MODE_2W_DTR
RS485_MODE_2W_AUTO
3. To set the RS-485 transceiver control mode, use
NISERIAL_SET_RS485_MODE
and DeviceIoControl. For