Measurement Computing Personal488 rev.3.0 For DOS & Windows 3.Xi - Manual (Page 157)

9C. External Device Interfacing II. SOFTWARE GUIDES - 9. Driver488/SUB
II-142 Personal488 User’s Manual, Rev. 3.0
device, from the initialization file to the application program. Each external device must have a
name to identify its configuration to Driver488/SUB. The name can then be used to obtain a
handle to that device which will be used by all of the Driver488/SUB commands. External device
names consist of 1 to 32 characters, and the first character must be a letter. The remaining
characters may be letters, numbers, or underscores (
_ ). External device names are case
insensitive; upper and lower case letters are equivalent. ADC is the same device as adc .
•
IEEE Bus Address: This is the setting for the IEEE 488 bus address of the board. It will be
checked against all the devices on the bus for conflicts. The IEEE 488 bus address consists of a
primary address from
00 to 30 , and an optional secondary address from 00 to 30 . Where required,
Driver488/SUB accepts a secondary address of -1 to indicate “NONE.”
•
Timeout (ms): The time out period is the amount of time that data transfers wait before assuming
that the device does not transfer data. If the time out period elapses while waiting to transfer data,
an error signal occurs. This field is the default timeout for any bus request or action, measured in
milliseconds. If no timeout is desired, the value may be set to zero.
•
Device Type: This field specifies the type of device represented by the external device name
selected.
•
Bus Terminators: The IEEE 488 bus terminators specify the character(s) and/or end-or-identify
(
EOI ) signal that is to be appended to data that is sent to the external device, or mark the end of
data that is received from the external device.
Note: Because secondary addresses and bus terminators are specified by each handle, it may be
useful to have several different external devices defined for a single IEEE 488 bus device. For
example, separate device handles would be used to communicate with different secondary
addresses within a device. Also, different device handles might be used for communication of
command and status strings (terminated by carriage return/line feed) and for communication
of binary data (terminated by
EOI ).
Note: If installation or configuration problems exist, refer to “Section IV: Troubleshooting.”
To save your changes to disk, press . All changes will be saved in the directory where you
installed Driver488/SUB. If at any time you wish to alter your Driver488/SUB configuration, simply
rerun
CONFIG ..
9C. External Device Interfacing
Topics
•
Introduction................................................................................... II-141
Subroutine Calls.......................................................................................... II-142
•
Configuration of Named Devices .............................................. II-142
•
Use of External Devices............................................................... II-143
•
Extensions for Multiple Interfaces ........................................... II-144
Duplicate Device Names............................................................................. II-144
Access of Multiple Interfaces ..................................................................... II-144
Example ........................................................................................................ II-145
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/SUB controls I/O adapters and their attached external devices. In turn, Driver488/SUB is
controlled via subroutine calls.