Lambda SR474 User manual

Operation Manual
Four Channel Shutter Driver
SR474
Stanford Research Systems
Revision 1.0 •February 9, 2009
Distribution in the UK & Ireland
Lambda Photometrics Limited
Lambda House Batford Mill
Harpenden Herts AL5 5BZ
United Kingdom
E: [email protected]
W: www.lambdaphoto.co.uk
T: [phone]
F: [phone]

Certification
Stanford Research Systems certifies that this product met its published specifications at the time
of shipment.
Warranty
This Stanford Research Systems product is warranted against defects in materials and workman-
ship for a period of one (1) year from the date of shipment.
Service
For warranty service or repair, this product must be returned to a Stanford Research Systems
authorized service facility. Contact Stanford Research Systems or an authorized representative
before returning this product for repair.
Information in this document is subject to change without notice.
Copyright c Stanford Research Systems, Inc., 2009. All rights reserved.
Stanford Research Systems, Inc.
1290–D Reamwood Avenue
Sunnyvale, CA 94089 USA
Phone: [phone] •Fax: [phone]
www.thinkSRS.com •e-mail: [email protected]
Printed in U.S.A. Document number 9-01635-903
SR474 Four Channel Shutter Driver

Contents
General Information iii
Safety and Preparation for Use ................ iv
Line Voltage ........................... iv
Line Cord and Grounding ................... iv
Line Fuse ............................. iv
Service .............................. iv
Environment ........................... iv
Laser Safety ........................... v
Symbols ............................. vi
Notation ............................. vii
Specifications .......................... viii
1 Getting Started 1 – 1
1.1 Introduction to the Instrument ............. 1–2
1.2 Front-Panel Operation .................. 1–2
1.3 The SR474 Rear Panel .................. 1–7
2 Remote Operation 2 – 1
2.1 Index of Common Commands .............. 2–2
2.2 Alphabetic List of Commands .............. 2–4
2.3 Introduction ........................ 2–6
2.4 Interface Configuration .................. 2–6
2.5 Commands ......................... 2–6
2.6 Command List ....................... 2–8
2.7 Error Codes ........................ 2–22
i

ii Contents
SR474 Four Channel Shutter Driver

General Information
The SR474 Four Channel Shutter Driver is a flexible instrument ca-
pable of driving and providing I/O interfaces for up to four external
SR470 Series Laser Shutter heads.
The shutter heads can be controlled through rear-panel TTL level
inputs that accept external timing signals. Alternately, each of the
four channels can be individually controlled manually through front
panel buttons or through a remote interface.
The Global Control section of the front-panel allows you to set all
channels to their “normal” or “Normal” states. Remote operation
is supported with GPIB, RS-232 and Ethernet computer interfaces.
All instrument functions can be controlled and read over any of the
interfaces. Shutter faults are automatically detected and result in
audible, visible and electronic alarms.
iii

iv General Information
Safety and Preparation for Use
Dangerous voltages, capable of causing injury or death, are present
WARNING in this instrument. Use caution whenever the instrument covers
are removed. Do not remove the covers while the unit is plugged
into a live outlet.
Never connect any of the shutter output ports to anything besides an
CAUTION SR470 Series Laser Shutter head.
Line Voltage
The universal input power supply of the SR474 accommodates any
voltage in the range 90 VAC to 260 VAC, with a frequency in the range
47 Hz to 63 Hz.
Line Cord
The SR474 has a detachable, three-wire power cord for connection
to the power source and to a protective ground. The exposed metal
parts of the instrument are connected to the outlet ground to protect
against electrical shock. Always use an outlet which has a properly
connected protective ground.
The shields of the six rear-panel BNC ports, the rear-panel Chassis
Ground binding post, and the metal chassis of the instrument are all
connected to Earth through the power-line-outlet ground.
Line Fuse
There are two line fuses internal to the SR474 that may not be serviced
by the user.
If no front panel LEDs are lit when line power is applied and the
power switch is in the “on” position, contact Stanford Research Sys-
tems.
Service
Do not attempt to service or adjust this instrument unless another
person, capable of providing first aid or resuscitation, is present.
Do not install substitute parts or perform any unauthorized modi-
fications to this instrument. Contact the factory for instructions on
how to return the instrument for authorized service and adjustment.
SR474 Four Channel Shutter Driver

General Information v
Environment
This product is intended for use only in a clean and dry laboratory
environment. Operation in other environments may cause damage
to the product. To reduce the risk of fire or electrocution do not
expose this product to rain or excessive moisture. Be careful not to
spill liquid of any kind onto or into the product.
Laser Safety
Certain hazards are always present when working with laser radia-
tion. Visible and invisible beams of light have the potential to cause
serious bodily injury including blindness or death and to cause sig-
nificant damage to property. While the SR474 is designed for use
with laser systems, it is fully the users responsibility to ensure
WARNING that safe operating conditions are maintained and to provide for
fail-safe operation whenever an equipment failure could lead to a
hazardous situation.
SR474 Four Channel Shutter Driver

vi General Information
Symbols you may Find on SRS Products
Symbol Description
Alternating current
Caution - risk of electric shock
Frame or chassis terminal
Caution - refer to accompanying documents
Earth (ground) terminal
Battery
Fuse
On (supply)
Off (supply)
SR474 Four Channel Shutter Driver

General Information vii
Notation
The following notation will be used throughout this manual.
A warning means that injury or death is possible if the instructions
WARNING are not obeyed.
A caution means that damage to the instrument or other equipment
CAUTION is possible.
Typesetting conventions used in this manual are:
•Front-panel buttons are set as Button .
•Front-panel indicators are set as Remote.
•Remote command names are set as *IDN?.
•Literal text other than command names is set as OFF.
Remote command examples will all be set in monospaced font. In
these examples, data sent by the host computer to the SR474 are set
as straight teletype font, while responses received by the host
computer from the SR474 are set as slanted teletype font.
SR474 Four Channel Shutter Driver

viii General Information
Specifications
Operation
Shutter Type SR470 Series Laser Shutters.
Shutter Outputs Four independent channels.
Shutter State Shutter states can be individually controlled, ei-
ther manually from front-panel inputs or from
external TTL level inputs.
Shutter Polarity Each channel can be individually set for “nor-
mally open” or “normally closed” operation us-
ing rear-panel DIP switches.
Channel Enable Front-panel Enable buttons individually en-
able or disable each channel.
Global Control Front-panel global Reset and Set buttons
command all shutter channels under manual
control to their Normal or Normal states.
Alignment Mode Front-panel Align buttons for each channel (ac-
tive when in manual mode) open and close shut-
ters at 1 Hz chopping rate to assist with mechan-
ical alignment.
Gate/Inhibit The rear panel aux i/o port can be configured
to allow or disallow TTL control of one or all
shutter channels depending on the value of an
input TTL level.
Fault Detection
and Reporting Automatic detection of shutter disconnect or
fault, with indicator LEDs for each channel.
Rear panel TTL Alarm output plus audible
alarm, which can be muted from the front panel.
Display Blanking Front panel LEDs can be disabled by holding the
front-panel Local button for 2 s.
Remote Operation Shutter polarity and some communications
parameters are controlled by rear-panel DIP
switches. All other instrument functions are
controllable over GPIB, RS-232, and Ethernet
interfaces.
SR474 Four Channel Shutter Driver

General Information ix
Electrical and Mechanical
Shutter Outputs Voltages +12 VDC, +4.5 VDC
Current limits 1.20 A max (12 VDC)
per channel 0.25 A max (4.5 VDC)
Signal lines Serial TX, Serial RX, logic-level control
Connector type Mechanically compatible
with 6-pin IEEE 1394 cables.
Cable length 10 ft (3 m) max
Cable shield Grounded or floating (internal jumpers)
I/O ports Level inputs 4 TTL compatible rear panel input BNC connectors,
internally pulled up to +3.3 VDC through 100 kΩ.
Auxiliary I/O 1 rear-panel BNC connector;
TTL level, multi-purpose.
Alarm output 1 rear-panel TTL output BNC connector
Interfaces Shutter outputs 4 rear-panel shutter connectors
Host interface RS-232; DB–9 (female) DCE
GPIB
Ethernet; 10/100Base-T
Operating Temperature 0◦Cto40◦C, non-condensing
Power 90 VAC to 260 VAC, 47 Hz to 63 Hz
85 W max
Physical Weight 7 lbs
Dimensions 8.25 W×4 H×11 D
SR474 Four Channel Shutter Driver

xGeneral Information
SR474 Four Channel Shutter Driver

1 Getting Started
This chapter gives you the necessary information to get started
quickly with the SR474 Four Channel Shutter Driver.
In This Chapter
1.1 Introduction to the Instrument ............. 1–2
1.1.1 Overview ..................... 1–2
1.1.2 Power-on State .................. 1–2
1.2 Front-Panel Operation .................. 1–2
1.2.1 Individual channel controls ........... 1–2
1.2.2 Global controls .................. 1–5
1.2.3 Remote lockout and front-panel operation . . 1 – 6
1.2.4 Restoring factory default configuration .... 1–7
1.3 The SR474 Rear Panel .................. 1–7
1.3.1 Power entry .................... 1–8
1.3.2 Chassis ground .................. 1–8
1.3.3 TTL Inputs ..................... 1–8
1.3.4 Shutter connectors ................ 1–8
1.3.5 Aux I/O port .................... 1–9
1.3.6 Alarm output ................... 1–10
1.3.7 Shutter polarity switches ............ 1–10
1.3.8 Remote interfaces ................. 1–10
1.3.9 Shutter grounding considerations ....... 1–12
1–1

1–2 Getting Started
1.1 Introduction to the Instrument
The SR474 Four Channel Shutter Driver is ideally suited for appli-
cations requiring one or several laser shutters in situations where
external timing or control signals are available.
1.1.1 Overview
The basic function of the SR474 Four Channel Shutter Driver is to
provide power, manual control, and I/O interfaces to between one
and four SR470 Series Laser Shutters. The shutters connect to outputs
on the rear panel of the instrument, and can be controlled by rear-
panel TTL level inputs or manually from either the front panel or
remote interfaces.
1.1.2 Power-on State
The SR474 stores its operation state in non-volatile memory, includ-
ing the configurations of the four shutter channels and the remote
interfaces.
At power-on, the SR474 will return to its previous configuration after
a brief system check and initialization.
1.2 Front-Panel Operation
The front panel of the SR474 (Figure 1.1) provides simple controls
for the operator and displays the shutter states at a glance. The
panel is divided into five sections: four identical sections that each
correspond to a single shutter channel, and a Global Control section.
1.2.1 Individual channel controls
The four shutter channels can be individually controlled and moni-
tored through the front panel sections labeled “Channel 1” through
“Channel 4.” The interface for each channel is identical.
The top half of the channel interface has two keys, State and
Enable along with status indicators for four possible states that
are possible for each shutter channel: OPEN,CLOSED,OFF, and
FAULT. These states are mutually exclusive and in most cases ex-
actly one of the four indicators is lit.
The bottom half of the channel interface has the key Source and as-
sociated indicators for selecting and monitoring the mode of channel
control. The Align key provides automatic opening and closing to
assist with mechanical alignment of your shutter head.
SR474 Four Channel Shutter Driver

1.2 Front-Panel Operation 1–3
Figure 1.1: The SR474 front panel.
1.2.1.1 State key
The State key for each channel toggles the state of that channel’s
shutter head between open and closed when the channel is enabled
and in manual control mode.
When a channel is switched away from manual control, the “man-
ual state” of the channel is remembered for when it is eventually
switched back to manual control.
1.2.1.2 Enable key
The Enable key for channel nturns on or offthe the shutter head
connected to the channel noutput.
If a given channel is initially in the OFF state, then pressing Enable
will cause the SR474 to attempt to enable the shutter head connected
to that channel. If the head powers on successfully, the channel will
display its state with either the OPEN or CLOSED indicator.
If Enable is pressed when there is not a shutter head present on that
channel, or if there is head but it reports a fault, the channel will not
be enabled, but will instead light up the FAULT indicator. This also
turns on the audible alarm, if not muted, and causes the rear-panel
alarm output to be asserted. In the event of a fault in the channel,
pressing Enable will clear the FAULT indicator and to return the
channel to the OFF state.
SR474 Four Channel Shutter Driver

1–4 Getting Started
Note: The shutter “logic” power supply (at +4.5 VDC) is always
provided to each connected shutter when the SR474 is powered on,
whether or not the channel is enabled. This is a separate power
supply from the +12 VDC line that provides power to the motor
(coil) in an attached shutter head.
When a channel of the SR474 is in the OFF state, a shutter head con-
nected to that channel is said to be in Standby mode. In this mode,
the logic power supply provides power for serial communications,
but the +12 VDC power supply is not available to change the po-
sition of the shutter blade. The shutter blade position is therefore
indeterminate.
1.2.1.3 Source key
The Source key for channel nselects the mode of control for a
shutter head connected to the channel noutput.
Two of the indicators by the key, TTL and Manual, are mutually
exclusive and indicate which of the two possible control modes is
selected for the shutter. Pressing the Source key will toggle between
these two modes.
In the Manual source mode, the state of the shutter is controlled to
be open or closed by direct user input, as selected by the State key
and its indicators (§1.2.1.1).
In the TTL source mode, the state of the shutter is controlled by the
level of the rear-panel TTL input for that channel. When the rear-
panel TTL input is high (unasserted), the shutter is commanded to
be in the Normal state. When the TTL input is low (asserted), the
shutter is commanded to be in the Normal state.
The polarity of each shutter channel is either normally open or nor-
mally closed as determined by the configuration of the rear-panel
DIP switches (§1.3.7).
The third indicator near the Source key is the Remote indicator.
This indicates when the instrument is addressed over a remote in-
terface. The channel is then in the Remote mode. Local control of
the channel can be re-established by pressing the Source key. The
mode can also be cleared for all channels at once by pressing the
Local key in the lower left hand coner of the front panel. See also
§1.2.3 for more about remote and lockout modes.
1.2.1.4 Align key
The Align key for each channel enables an alignment mode, where
the shutter is commanded to chop (open and close) at a rate of ap-
SR474 Four Channel Shutter Driver

1.2 Front-Panel Operation 1–5
proximately 1 Hz. This mode is intended to help facilitate mechanical
alignment and identification of the shutter heads. This function is
only available when connected shutter head is enabled and in the
Manual control mode.
1.2.2 Global controls
The four keys in the Global Control section of the front panel provide
functions that address all four channels or the instrument as a whole.
1.2.2.1 Global manual control: Set and Reset
The top half of the Global Control section has two keys, Reset
and Set . These keys affect all channels that are currently enabled
and in the Manual source mode, and are only operational when the
instrument is under local control. Pressing Set commands each
affected shutter channel to its Normal state, and pressing Reset
returns each affected shutter channel to its Normal state.
If a shutter channel is not in Manual mode when Reset or Set
is pressed, the saved “manual state” will be updated for when the
channel is eventually returned to manual control.
Holding down either Reset or Set for approximately two seconds
will force global Set/Reset, meaning that all four channels will be
placed in the Manual source mode and all enabled channels will be
commanded to their respective Normal /Normal states.
Each shutter channel on the SR474 can independently be configured
to be normally open or normally closed by setting rear-panel DIP
switches (§1.3.7).
1.2.2.2 Alarm key
The Alarm key toggles the configuration of the SR474 audio alarm
between the states of Audible and Mute.
The rear-panel Alarm output (§1.3.6) is asserted (pulled low) when-
ever at least one of the four shutter channel FAULT indicators is lit.
In the event that an alarm is asserted, the SR474 will continuously
emit a loud siren-like noise to attract attention if the Audible mode
is selected. No alarm noise will be made while the Mute mode is
selected.
An active audio alarm can be silenced by pressing the Alarm key,
switching the unit to the Mute state. An alarm can also be silenced by
clearing the fault that is causing the alarm– for example, by pressing
SR474 Four Channel Shutter Driver

1–6 Getting Started
the Enable key to turn offa channel that has its FAULT indicator
lit.
The alarm functions are intended to help draw attention to fault con-
ditions that might otherwise be difficult to detect. For example, if
an enabled shutter head is disconnected, that shutter’s channel will
be placed into the fault condition. The expected configuration of the
SR474 is also saved, such that if a shutter head is accidentally discon-
nected during a power outage, a fault will be declared in that channel
when power is restored, and cannot be cleared by merely cycling the
power. Operator action is required to clear a fault condition.
1.2.2.3 Utility Functions: Local, Display Off
The bottom button in the Global Control section is the Local key.
Pressing this key restores the instrument to local control after it has
been accessed over one of the remote interfaces. See also §1.2.3 for
more about local and remote modes.
The Local key has an alternate function, which is to turn offmost
of the front-panel LED indicators when the key is held down for 2 s.
When this is done, all front panel LEDs will go dark except for the
Disp Offindicator by the Local key. To turn the display back on,
hold the key for 2 s again. Turning offthe display may be helpful
because it prevents the OPEN and CLOSED indicators from blinking
synchronously with shutter operation; a potential nuisance in certain
laboratory environments.
1.2.3 Remote lockout and front-panel operation
When a host computer accesses the SR474 over one of the remote
interfaces, it normally places the unit in the Remote state, where
most manual input is not allowed. This is indicated by the Lockout
indicator, which is located by the Local key at lower left corner of
the front panel.
To return to front panel operation from Remote mode, press the
Local key. It is also possible to individually return any of the four
shutter channels to local control by pressing its Source key. This
selection takes the relevant channel out of remote mode.
The SR474 can also be placed into complete lockout mode by using
the LOCK? query over a remote interface. In this mode the Lockout
indicator is lit, but the instrument will not respond to any front panel
input, including the Local key. This mode can only be disabled
using the UNLK? query over a remote interface or by cycling the
power to the instrument, as described in §2.6.4.
SR474 Four Channel Shutter Driver

1.3 The SR474 Rear Panel 1–7
1.2.4 Restoring factory default configuration
The SR474 can be reset to its factory-default settings by power cycling
the unit with the Reset key depressed. This is equivalent to sending
the *RST command over one of the remote interfaces. It performs
the following actions:
1. Turn offall shutter channels
2. Place all shutters in manual control
3. Set all shutters to the unasserted (Normal ) state
4. Turn offchopping (alignment mode) on all channels
5. Select Audible alarm mode
6. Turn the display on
7. Select manual configuration for the rear Aux I/O port
Recalling factory default settings this way does not affect the interface
configuration. Most of the interface configuration is determined by
the rear panel DIP switches. However, an internal ip address can
be configured via the remote interfaces. These values may be reset
to factory defaults by power cycling the unit with the Local key
depressed. In this case the internal IP addresses are set to 0.0.0.0, and
compatibility mode is disabled.
Figure 1.2: The SR474 rear panel.
1.3 The SR474 Rear Panel
The rear panel of the SR474 (see Figure 1.2) provides input and
output connectors for controlling the four shutters, an alarm output,
SR474 Four Channel Shutter Driver

1–8 Getting Started
an auxiliary I/O port, a chassis-grounded binding post, three remote
interfaces, configuration DIP switches, and the power entry module.
The SR474 serial number and ethernet MAC address are printed on
a label located on the back side.
1.3.1 Power entry
The power entry module is located on the upper left side of the rear
panel and contains an integrated power switch.
The universal input power supply of the SR474 accommodates any
voltage in the range 90 VAC to 260 VAC, with a frequency in the range
47 Hz to 63 Hz.
The SR474 has a detachable, three-wire power cord for connection
to the power source and to a protective ground. The exposed metal
parts of the instrument are connected to the outlet ground to protect
against electrical shock. Always use an outlet which has a properly
connected protective ground.
1.3.2 Chassis ground
This binding post is connected to the SR474 chassis and to earth
ground.
1.3.3 TTL Inputs
The primary control inputs for the SR474 Four Channel Shutter
Driver are the four rear-panel BNC inputs corresponding to the four
shutter channels.
Each channel’s input, labeled “TTL In,” accepts an externally gen-
erated logic-level input signal that controls the state of a shutter
connected to that channel, when the channel is both enabled and
set to the TTL source mode. The inputs are internally pulled up to
+3.3 VDC through 100 kΩand are compatible with +5 VDC (TTL)
input signals.
The inputs are active low. A signal that is unasserted, i.e., logically
high or open (disconnected), commands the associated shutter to
its Normal state. An input signal that is asserted, i.e., pulled low,
commands an affected shutter to its normal state.
Note: The shield of each input BNC is connected to earth ground.
1.3.4 Shutter connectors
The SR474 has four output connectors, each of which provides power
and interface connections for an external SR470 Series Laser Shut-
SR474 Four Channel Shutter Driver