Bus Commands - Keithley 2016 User Manual

D-8 IEEE-488 Bus Overview

Bus commands

The instrument may be given a number of special bus commands through the IEEE-488 inter-
face. This section briefly describes the purpose of the bus commands which are grouped into the
following three categories.
1.
2.
3.
4.
These bus commands and their general purpose are summarized in
Table D-1
IEEE-488 bus command summary
Command type
Uniline REN (Remote Enable)
EOI
IFC (Interface Clear)
ATN (Attention)
SRQ
Multiline LLO (Local Lockout)
Universal DCL (Device Clear)
SPE (Serial Enable)
SPD (Serial Poll Disable)
Addressed SDC (Selective Device Clear)
GTL (Go To Local)
Unaddressed UNL (Unlisten)
UNT (Untalk)
Common —
SCPI —
Uniline Commands — Sent by setting the associated bus lines true. For example, to
assert REN (Remote Enable), the REN line would be set low (true).
Multiline Commands — General bus commands which are sent over the data lines with
the ATN line true (low).
Common Commands — Commands that are common to all devices on the bus; sent with
ATN high (false).
SCPI Commands — Commands that are particular to each device on the bus; sent with
ATN (false).
Command
State of
ATN line
X Set up devices for remote operation.
X Marks end of transmission.
X Clears interface.
Low Defines data bus contents.
X Controlled by external device.
Low Locks our local operation.
Low Returns device to default conditions.
Low Enables serial polling.
Low Disables serial polling.
Low Returns unit to default conditions.
Low Returns device to local.
Low Removes all listeners from the bus.
Low Removes any talkers from the bus.
High Programs IEEE-488.2 compatible
instruments for common operations.
High Programs SCPI compatible instruments for
particular operations.
Table D-1.
Comments