Measurement Computing Personal488 rev.3.0 For DOS & Windows 3.Xi - Manual (Page 218)

II. SOFTWARE GUIDES - 10. Driver488/W31 10C. External Device Interfacing
Personal488 User’s Manual, Rev. 3.0 II-203
10C. External Device Interfacing
Topics
•
Introduction .................................................................................. II-202
Subroutine Calls.................................................................................................II-202
•
Configuration of Named Devices.............................................. II-202
•
Use of External Devices .............................................................. II-204
•
Extensions For Multiple Interfaces ......................................... II-204
Duplicate Device Names .............................................................................II-205
Access of Multiple Interfaces......................................................................II-205
Example .........................................................................................................II-205
Introduction
This Sub-Chapter is a technical review of external device interfacing. It contains information on how
to use external devices and multiple interfaces.
Driver488/W31 controls I/O adapters and their attached external devices. In turn, Driver488/W31 is
controlled via subroutine calls.
Driver488/W31 communicates directly with I/O adapters such as an IEEE 488 interface board. More
than one I/O adapter may reside on a single plug-in board. For example, the IEEE 488 interface board
contains the IEEE 488 I/O adapter.
I/O adapters connect to external devices such as digitizers, multimeters, plotters, and oscilloscopes
(IEEE 488 interface); and serial devices such as printers, plotters, and modems. However,
Driver488/W31 allows direct control of IEEE 488 external devices only.
Note: To reiterate, Driver488/W31 supports IEEE 488 external devices, and does not support serial
external devices.
Driver488/W31 is controlled by sending data and commands, and receiving responses and status by
subroutine calls. This method is the only Application Program Interface, API, available to connect the
application (user’s) program to Driver488/W31.
Subroutine Calls
The subroutine API is a library of subroutines linked to the application program that are invoked like
any other subroutines in that programming language. Once invoked, these routines can control
Driver488/W31.
Configuration of Named Devices
Named devices provide a method to maintain a permanent record of an external device’s configuration
that does not change between application programs. Once the configuration of a particular external
device is established, its Driver488/W31 configuration for that device will remain the same until the
next time you reconfigure it or unload and reload the driver. The external devices supported by
Driver488/W31 are IEEE 488 external devices only.
External devices are most easily configured at installation. For Driver488/W31, the device names,
terminators, timeout period, and bus addresses may be entered into a configuration file (either manually
or using the
CONFIG utility) which contains the device configuration information. This configuration
file is automatically read during driver load to install the configured named devices. The application
program can then refer to the external device by name and have all of the configuration information
automatically set.