Stanford Research Systems SR470, Operation Manual

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1.2 Front-Panel Operation 1 – 5
1.2.2.2 Shutter polarity
An SR470 Series Laser Shutter head may be operated either as a nor-
mally open (N.O.) or normally closed (N.C.) shutter. The normal
state refers to the unasserted state of the shutter, which is (for exam-
ple) the state in which the shutter idles when a trigger has not yet
come.
The polarity may be selected by pressing [Shift] [N.O.] or [Shift]
[N.C.]. These alternate (“shifted”) functions are located above the [1]
and [2] keys in the “Modify” section of the front panel.
The currently selected shutter polarity is indicated on the timing
diagram near the center of the SR470 front panel. On the left hand
side of the diagram, one of the two indicators
N.O. or N.C. will be lit
to indicate the polarity.
1.2.2.3 Shutter status
The shutter operational status may be determined by looking at the
OPEN , FAULT , and CLOSED indicators in the lower left hand corner.
When an SR470 Series Laser Shutter head is plugged in, powered,
and operating properly, either the
OPEN or CLOSED will be lit,
showing the position of the shutter blade. (Note: It is possible to
disable the front panel LEDs; see
§
1.2.5.6.)
The FAULT indicator on the SR470 may be lit either if the shut-
ter head reports a fault or if the shutter head is unexpectedly un-
plugged. The fault indicator may be cleared by pressing the [
]
(reset) key. Pressing [ ] when a fault condition is present will power
down the shutter head (if attached), and turn o
ff
the OPEN , FAULT ,
and CLOSED indicators. See also
§
1.2.2.5 for more information about
faults and alarms.
When all three of the OPEN , FAULT , and CLOSED indicators are
o
ff
, that indicates that there is not presently a shutter head that is
both plugged in and powered. If there is not a shutter head present,
the words “
” will usually be displayed on the nu-
meric display. If a shutter head is present but powered o
ff
, the word
“ ” may be appear on the seven segment display.
1.2.2.4 Turning on the shutter head
It is possible to manually power down the shutter head by pressing
[Shift][Sleep].
When a shutter head is plugged in but not powered on, it is said to
be in
standby , also known as sleep mode. From this state, pressing
SR470 Shutter Controller