Section 4-Ieee-488 Programming; Introduction; Shortcut To Ieee-488 Operation; Bus Connections - Keithley 595 Instruction Manual

SECTION 4
IEEE-488 PROGRAMMING
4.1 INTRODUCTION
The IEEE-488 bus is an instrumentation data bus with hard-
ware and programming standards origir@y adopted by the
IEEE (Tnstitute of Eleclxical and Electronic Engineers) in 1975
and given the IEEE-488 designation. ln l!Z3 standards were
upgraded into the lEJ%E-48&1978 standards. The Model 595
conforms to these standards.
4.2 SHORTCUT TO IEEE-488 OPERATION
The information in this paragraph is intended to provide
immediate hands-on experience in bus operation using the
HP-85 computer with some of the most often used
commands.
J.n general, IEEE-488 bus operation consists of connectiig
the instrument to the bus, setting the IEEE-488 address,
and then progr arming the insinunent to listen ancUor talk.
Perform the following procedure to get started using the
Model 595 over the IEEE-488 bus:
l. Bus Connections
A. Install the HP 8293ZA GPIB interface and an I/O ROM
in the HP-85.
B. Connect the GPIB interface of the computer to the
IEEE-488 connector on the rear panel of the Model
595.
Note: Complete information on bus coti&tions is
contained in paragraph 4.3.
2. Primary Address Selection-The primary address of the
Model 595 is factory set to 28. If the instrument is cur-
rently set to a different address, change it back to 28. The
current address can be checked and changed with the
front panel IEEE-488 address program.
Note: The detailed procedure for address selection is
contained in paragaph 4.4.
3. Progmnuning the Model 595 to Listen-Enter the follcw-
ing statements into the computer to place the instrument
in the capacitance function. Make sure to press the END
LJNE key after each line is typed.
When END LINE is pressed the first time, the instru-
ment will be placed in the remote, listen state by the
REMOTE command. The instrument is identifiedby the
number 728; where 7 is the controller's interface select
code and 28 is the address of the Model 595. When END
LINE is pressed the second time, the OUTPUT coti-
mand will instruct the instnunent to go to the
capacitance function (FOX command).
4. Programming the Model 595 to Talk-Enter the follow-
ing statements to instrud~the instrument to output a
reading over
the bus to the computer:
DIM kB[SMl
EHTER 72s; AS
DI~SP A$
When ENDLINE is pressed the first time, the computer
wiU dimension (DIM) an array (A$) that will allow all
37 characters of the reading to be recognized. Normally,
the computer will only recognize 18 chamcters at a time.
When END LlNE is pressed the second time, the ENTER
command will instruct~the instrument to send a reading
to the computer. When END LINE is pressed the third
time the reading will be displayed on the computer CKK
4.3 BUS CONNECTIONS
The following paragraphs provide the detailed information
needed to connect instrumentation to the IEEE-488 bus.
4.3.1 Typical Controlled Systems
system conflgomtions are as varied as their applications.
To obtain as mucl~ v~rs@ility as possible, the IEEE-488 bus
was designed so that additional instmmentation could be
easily added. Because of this versatility, system complexity
can range from very simple to extremely complex.
Figure 41 shows two possible system configurations. Figure
&l(A) shows the simplest possible controlled system. The
controller is used to send commands to the instrument,
which sends data back to the controller.
4-l