Uniline Commands - Keithley 6430 Instruction Manual

Table D-1
IEEE-488 bus command summary
Command type Command
Uniline REN (Remote Enable)
EOI (End Or Identify)
IFC (Interface Clear)
ATN (Attention)
SRQ (Service Request)
Multiline LLO (Local Lockout)
Universal DCL (Device Clear)
SPE (Serial Poll Enable)
SPD (Serial Poll Disable)
Addressed SDC (Selective Device Clear)
GTL (Go To Local)
Unaddressed UNL (Unlisten)
UNT (Untalk)
Common –
SCPI –

Uniline commands

ATN, IFC and REN are asserted only by the controller. SRQ is asserted by an external
device. EOI may be asserted either by the controller or other devices depending on the direc-
tion of data transfer. The following is a description of each command. Each command is sent
by setting the corresponding bus line true.
REN (Remote Enable) — REN is sent to set up instruments on the bus for remote opera-
tion. When REN is true, devices will be removed from the local mode. Depending on device
configuration, all front panel controls except the LOCAL key (if the device is so equipped) may
be locked out when REN is true. Generally, REN should be sent before attempting to program
instruments over the bus.
EOI (End or Identify) — EOI is used to positively identify the last byte in a multi-byte
transfer sequence, thus allowing data words of various lengths to be transmitted easily.
State of
ATN line Comments
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 out 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.
IEEE-488 Bus Overview D-7