Triggering; Trigger Sources - Keithley 707A Instruction Manual

Operation
Table
4~7
Make/break and hreak/make
front
panel operation
Present State
Action Next
State
Don't
Care
Select
Make/Break Make/Break
Select
Break/Make
Break/Make
Make/Break
Select
Break/Make Break/Make
De-select
Make/Break
Don't
Care
Break/Make
Select
Make/Break Make/Break
De-select
Break/Make
Don't Care
The
optional
light
pen
can be used
to toggle the
LED
states
directly.
The
light
pen can
also
select
rows
for
make/break or
break/make
operation
from
slave
units.
The
row
selection
is
in effect for
all
units
connected
in a
master/slave
configuration.
4.11 Triggering
When
a
Model
707A
stand-alone or master
unit
is
triggered,
the stored relay setup
from
RELAY
STEP+1
is
sent to the
relays.
Triggers
are
enabled with
the front panel
ENABLE
key of
the
TRIGGER
group
(see
Figure
4-15).
This key
tog-
gles
between
triggers
enabled and
triggers disabled.
When
triggers are
enabled,
the
ENABLE LED
is
lit.
TRIGGER
E
NABLE
Od
S
OURC
E
O
M ANUA
L
o
V J
Figure
41
Trigger keys
The
maximum
trigger rate
is
specified with
no make/break
or
break/make rows
selected.
As
will
be described
in
paragraph
4.1
1.3,
additional switching delays are necessary with
make/
break
or
break/make
operation.
4.11.1 Trigger sources
The programmed
trigger
source provides
the stimulus to
increment
to the next stored setup. Trigger sources
include:
• Front panel
MANUAL
key
—
When
triggers are
enabled,
this
key
is
always
operational (on stand-alone
and master
units)
regiudless of
the selected source
(unless the unit
is
placed
in
remote over the
IEEE-488
bus).
•
External
trigger
pulse
—
An
appropriate pulse, applied
to
the
EXTERNAL
T
RIGGER
INPUT
jack
on
the rear
panel, provides
the trigger stimulus.
•
IEEE command
triggers
—
IEEE-488 GET,
X,
or
talk
commands
provide
the
stimulus
when
the
appropriate
source
is
selected.
Select the trigger source as follows:
1
.
Press
SOURCE
and
note
that
the current trigger source
is
displayed:
TRIG
ON
EXT
This
is
the display
for
external triggering (the power-up
default).
Table 4-8
lists
the displays for
all
trigger
sources.
2.
Press
the
SCROLL
or
keys
until
the desired trigger
source
is
displayed.
Then
press
ENTER
to select
it
and
exit
menu
mode.
3. If
another source
is
scrolled to
before pressing
ENTER,
pressing
CANCEL
once
returns the old selection, press-
ing
it
again
exits
menu
mode.
Table 4-8
Front
panel messages
for
trigger sources
Message
Description
1
TRIG
ON
TALK
TRIG
ON
GET
TRIG
ON X
TRIG
ON
EXT
TRIG
ON KEY
IEEE
talk
command
IEEE
GET
command
IEEE
X
command
External trigger pulse
Front panel
MANUAL
key
only*
*tf triggers are enabled, pressing
MANUAL
emulates the selected trigger
source.
4-20