HP IBASIC Supplement 8-3
Interfacing with External Devices
Communication with Devices
Communication with Devices
GPIB Device Selectors
Since the GPIB allows several devices to be interconnected, each device
must be uniquely identified. Specifying the select code (such as 7 or 8) of
the GPIB interface to which a device is connected, is not enough to
uniquely identify each specific device on the bus.
Each device on the bus has a primary address that identifies it. This
address can be set by the user. It must be unique to allow individual
access of each device. When a particular GPIB device is to be accessed, it
must be identified with both its interface select code and its bus address.
The interface select code is the first part of an GPIB device selector.
IBASIC programs run inside an instrument and communicate with it
over an internal bus (interface select code 8). IBASIC programs can also
communicate with external devices using the instrument's GPIB
interface (select code 7).
The second part of an GPIB device selector is the device's primary
address, an integer in the range of 0 through 30. For example, to specify
the device on the interface at select code 7 with a primary address of 22,
use device selector 722. Secondary GPIB addressing is also supported for
those devices requiring it. These devices will have at least 5-digit service
selection such as 72201.
Since the analyzer is the only device on the internal interface, its
primary address on that interface is arbitrary and the instrument will
respond to any primary address with a select code equal to 8 (e.g., 800,
811, 822, etc.).
NOTE Each GPIB device address must have a unique GPIB address. The
analyzer is shipped from the factory with a primary address of 16. No
other device on the bus should use the same address.
Setting Device Addresses
The procedure for setting the address of an GPIB device is given in the
installation manual for each device. To set the address of the analyzer,
use the softkeys in the menu, or the SCPI
mnemonic SYST:COMM:GPIB:ADDR.
SYSTEM OPTIONS
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