Tabor 8020 - Bus Commands; Uniline Commands

NOTE
The programmed primary address is
briefly displayed during the power-up
cycle of the Model 8020. It is stored
in the non-volatile memory of the
instrument and is retained even when
power is turned off.
To check the present address, or to enter a new
one, proceed as follows:
1. Depress the [2nd] push-button once then de-
press the [ADR] push-button. The display will be
modified to display the following:
IExx
Where x may be any number from 0 to 30.
2. Use the MODIFIER [x1⇑] or the [x1 ⇓] push-
buttons for selecting a new GPIB primary address.
3. To store the newly selected primary address
depress [EXE]. The instrument then resumes normal
operation.
4-8. BUS COMMANDS
While the hardware aspect of the bus is essential,
the interface would be essentially worthless without
appropriate commands to control the communications
between the various instruments on the bus. This
paragraph briefly describes the purpose of the bus
commands, which are grouped into the following
three categories:
1. Uniline commands: Sent by setting the as-
sociated bus line low (true).
2. Multiline commands: General bus commands
which are sent over the data lines with the ATN
line low (true).
3. Device-dependent commands: Special com-
mands that depend on device configuration; sent
over the data lines with ATN high (false).
4. Common commands and queries: A special
set of commands that all devices must use and
does not depend on device configuration; sent over
the data lines in the same format as the device
dependent commands.
4-8-1. Uniline Commands
Uniline commands are sent by setting the associated
bus line to low. The ATN, IFC, and REN commands
are asserted only by the system controller. The SRQ
command is sent by an external device. The EOI
command may be sent by either the controller or
COMMAND TYPE COMMAND STATE OF COMMENTS
ATN LINE(*)
Uniline REN X Set up for remote operation
EOI X Sent by setting EOI low
IFC X Clears Interface
ATN Low Defines data bus contents
SRQ X Controlled by external device
Multiline Universal LLO Low Locks out front panel controls
DCL Low Returns device to default conditions
SPE Low Enable serial polling
SPD Low Disables serial polling Addressed
SDC Low Returns unit to default condition
GTL Low Returns to local control
GET Low Triggers device for reading
Unaddress UNL Low Removes all listeners from bus
UNT Low Removes all talkers from bus
Device- Dependent(**) High Programs Model 802020 for various
modes.
(*) X = Don’t Care, (**) See paragraph 4-9 for complete description
Table 4-3. IEEE-488 Bus Command Summary
IEEE-488.2 Operation Model 8020
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