National Instruments GPIB-232CV, Руководство пользователя

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Application Examples Appendix C
GPIB-232CV User Manual C-4 © National Instruments Corp.
Using the GPIB-232CV to Connect a HP7475
GPIB Plotter to a PC Serial Port
Many software packages provide printing and plotting utilities which use
your computer's serial port. If GPIB support is not specifically provided in
the package, you cannot communicate with a GPIB device. By using the
GPIB-232CV, you can avoid this situation because the GPIB-232CV allows
communication between the serial port and GPIB devices.
For example, an IBM PC running AUTOCAD sends data to the plotter by
transferring data through the computer's serial port. It cannot send data to a
GPIB plotter such as the HP7475 GPIB plotter. Because AUTOCAD
supports the HP7475 serial plotter, you can use the GPIB-232CV to convert
the serial data from AUTOCAD into GPIB data for the plotter. The GPIB-
232CV automatically takes care of the GPIB addressing and transparently
converts the data from one format to the other. To use the GPIB-232CV in
this way, follow these steps:
1. Start AUTOCAD and select Configure AUTOCAD from the Main
Menu. Select the HP7475 plotter and configure the rest of the
operating parameters that you need.
2. Configure your GPIB-232CV. Set it to operate in C mode with timeout
termination. Set the GPIB address of the plotter using the GPIB-
232CV configuration switches. Set the serial port parameters to
XON/XOFF disabled, 9600 baud, 7 data bits, 1 stop bit, and even
parity.
3. Power on the plotter, then power on the GPIB-232CV.
When the GPIB-232CV is powered on, it addresses the GPIB plotter. Any
data sent to the serial port by AUTOCAD is received by the GPIB-232CV
and stored in its internal buffer. The GPIB-232CV transfers the data to the
plotter over the GPIB connection as fast as the plotter can receive it.
Because the GPIB-232CV provides a data buffer that spools the data as it is
sent, the PC will be able to send data at serial rates instead of plotter rates.
Therefore, your data is output to the GPIB plotter by AUTOCAD in less
time than it would have taken to use the HP7475 serial plotter.