Sutter Lambda VF-5 User manual

One Digital Drive
Novato, CA 94949
Voice: 415-883-0128 Web: www.sutter.com
Fax: [phone] Email: [e-mail]
Lambda VF-5™
Tunable Optical Filter Changer
Control System
Operation Manual
Rev. 1.04a (20190606)

LAMBDA LS OPERATION MANUAL -– REV. 1.04A (20190606)
ii
Copyright © 2019Sutter Instrument Company. All Rights Reserved.
Lambda VF-5™ and Lambda VF-1™ are trademarks, and LAMBDA-10® and
SmartShutter®are registered trademarks, all of Sutter Instrument Company.

LAMBDA VF-5 OPERATION MANUAL – REV. 1.04A (20190606)
iii
DISCLAIMER
The Lambda VF-5 Variable Optical Filter Switcher is designed for the specific use of changing
filters and bandwidth into and out of an optical pathway and no other use is recommended.
This instrument is designed for use in a laboratory environment. It is not intended, nor
should it be used in human experimentation or applied to humans in any way. This is not a
medical device.
Do not open or attempt to repair the instrument. Extreme heat and high voltages are present
and could cause injury.
Do not allow unauthorized and/or untrained operative to use this device.
Any misuse will be the sole responsibility of the user/owner and Sutter Instrument Company
assumes no implied or inferred liability for direct or consequential damages from this
instrument if it is operated or used in any way other than for which it is designed.
SAFETY WARNINGS AND PRECAUTIONS
Electrical
Operate the Lambda VF-5 using 110-120 V AC, 60 Hz, or 220-240 V AC., 50 Hz line
voltage. This instrument is designed for connection to a standard laboratory power outlet
(Overvoltage Category II), and because it is a microprocessor--controlled device, it should
be accorded the same system wiring precautions as any 'computer type' system. A surge
protector and power regulator are recommended.
Fuse Replacement: Replace only with the same type and rating:
T1.0A, 250V, Time Delay (IEC 60127-2, Sheet III)
(Examples: Bussmann GDC-1A or S506-1R (RoHS); or
Littelfuse 218 001 or 218.001.P (RoHS))
A spare fuse is located in the power input module. Please refer to the fuse-replacement
appendix for more details on fuse ratings and for instructions on how to change the fuse.
Avoiding Electrical Shock and Fire-related Injury
Always use the grounded power supply cord set provided to connect the system to a
grounded outlet (3-prong). This is required to protect you from injury in the event that
an electrical hazard occurs.
Do not disassemble the system. Refer servicing to qualified personnel.
To prevent fire or shock hazard do not expose the unit to rain or moisture.
Optical Radiation
This system is designed for use in conjunction with high-intensity light sources. Failure to
comply with any of the following precautions may result in injury to the users of this device
as well as those working in the general area near the device.

LAMBDA VF-5 OPERATION MANUAL – REV. 1.04A (20190606)
iv
Never look into the optical pathway of the high intensity light sources typically used
with this instrument. Doing so can cause permanent eye damage.
The high-intensity light sources typically used with this instrument also produce a
significant amount of heat. Direct contact with the housing of those instruments can
cause serious burns.
Electromagnetic Interference
To comply with FDA and CE electromagnetic immunity and interference standards; and to
reduce the electromagnetic coupling between this and other equipment in your lab always
use the type and length of interconnect cables provided with the unit for the interconnection
of the filter wheel, host computer via serial RS-232 or parallel interface, or other equipment
via TTL connections (see the TECHNICAL SPECIFICATIONS appendix for more details).
Operational
Failure to comply with any of the following precautions may damage this device.
This instrument is designed for operation in a laboratory environment (Pollution Degree
I).
This unit is not designed for operation at altitudes above 2000 meters nor was it tested
for safety above 2000 meters.
DO NOT CONNECT OR DISCONNECT THE CABLES BETWEEN THE
CONTROLLER AND THE MECHANICAL UNIT (FILTER WHEEL) WHILE POWER IS
ON.
Please allow at least 20 seconds after turning the unit off before disconnecting the
mechanical units. Failure to do this may result in damage to the electronics.
Operate only in a location where there is a free flow of fresh air on all sides.
NEVER ALLOW THE FREE FLOW OF AIR TO BE RESTRICTED.

LAMBDA VF-5 OPERATION MANUAL – REV. 1.04A (20190606)
v
TABLE OF CONTENTS
DISCLAIMER ......................................................................................................................................iii
SAFETY WARNINGS AND PRECAUTIONS...................................................................................iii
Electrical .................................................................................................................................................iii
Avoiding Electrical Shock and Fire-related Injury.............................................................................iii
Optical Radiation ...................................................................................................................................iii
Electromagnetic Interference ...............................................................................................................iv
Operational .............................................................................................................................................iv
1. GENERAL INFORMATION ...........................................................................................................1
1.1 Introduction.......................................................................................................................................1
1.1.1 How to Use this Manual............................................................................................................1
1.1.2 Technical Support ......................................................................................................................1
1.2 General Description..........................................................................................................................1
1.2.1 Systems........................................................................................................................................4
1.3 Filter Wheel .......................................................................................................................................4
1.3.1 Mechanical Description .............................................................................................................4
1.3.2 Filter Wheels...............................................................................................................................4
1.3.2.1 Mechanical Description.......................................................................................................5
1.3.3 Filter Wheel Adapters................................................................................................................5
1.3.4 Cables ..........................................................................................................................................5
1.4 Controller...........................................................................................................................................5
1.4.1 Principles of Operation..............................................................................................................5
1.4.2 Rear Panel Connectors ..............................................................................................................5
1.4.3 Front Panel Controls .................................................................................................................7
1.4.3.1 Keypad ..................................................................................................................................7
1.4.3.2 Display ..................................................................................................................................8
1.6 Functional Description.....................................................................................................................8
1.6.1 Stepping Motor Operation ........................................................................................................8
2. INSTALLATION ............................................................................................................................11
2.1 Unpacking........................................................................................................................................11
2.2 Pre-Installation Instructions.........................................................................................................11
2.2.1 Vibrations..................................................................................................................................11
2.3 Installation Instructions ................................................................................................................12
2.3.1 Initializing the Lambda Vf-5 if Not Already Initialized or After Being Reset...................13
2.4 Setting the Wheel Rotation Speed (<LOCAL> <SPEED> <0> through <7>)..................17
2.5 Setting the Wheel Tilt Speed (<LOCAL> <SPEED> < λ> <0> through <3>) ...............17
3. OPERATIONS – GENERAL .........................................................................................................19
3.1 First Time Use ................................................................................................................................19
3.1.1 Line Power (Mains)..................................................................................................................19
3.2 Basic Operation...............................................................................................................................20
3.2.1 Initialization .............................................................................................................................20
3.3 Filter Wheel Assembly....................................................................................................................20
3.4 Make It Go .......................................................................................................................................21

LAMBDA VF-5 OPERATION MANUAL – REV. 1.04A (20190606)
vi
4. OPERATIONS – MANUAL CONTROL .......................................................................................23
4.1 Power up Sequence.........................................................................................................................23
4.2 Main Status Screen.........................................................................................................................23
4.3 The Lambda VF-5 Keypad.............................................................................................................23
4.4 Placing Lambda VF-5 into Local Mode ........................................................................................24
4.5 Immediate Key Control of Attached Devices (While in Local Mode)........................................24
4.6 Main Menu (F1) ..............................................................................................................................25
4.6.1 Test Mode Menu (F1 2) ...........................................................................................................26
4.6.1.1 Loop Test (F1 2 1) .............................................................................................................26
4.6.1.2 Demo (F1 2 2).....................................................................................................................26
4.7 Selecting the Filter Position ..........................................................................................................26
4.8 Selecting the Filter Switching Speed............................................................................................26
4.9 Error Detection and Recovery.......................................................................................................27
4.10 Movement Errors: Causes and Solutions..................................................................................27
4.11 Helpful Tips about Movement Errors ........................................................................................28
5. OPERATIONS: EXTERNAL CONTROL: GENERAL................................................................29
5.1 Principles of Operation...................................................................................................................29
5.2 External Control Interfaces...........................................................................................................29
5.2.1 Serial RS-232-C Interface Port with Control via Host Computer’s Built-in Device Driver
.............................................................................................................................................................29
5.2.2 USB Interface Port with Control via Direct Device Driver.................................................29
5.2.3 USB Interface Port with Control via Additional Virtual Com Port (VCP) Device Driver
.............................................................................................................................................................29
5.3 External Control Command Set....................................................................................................29
5.4 External Control Application Programming ...............................................................................29
5.5 Input Command Structure ............................................................................................................30
5.5.1 Commands Description ...........................................................................................................30
5.6 Command Descriptions ..................................................................................................................32
5.6.1 Switch to Wavelength Command (218d (DAh)) ...................................................................32
5.7 Filter Wheel Commands ................................................................................................................33
5.7.1 Filter Wheel Command Byte Encoding .................................................................................34
5.7.2 Set Wavelength Command Encoding ....................................................................................35
5.8 Special Commands..........................................................................................................................35
5.8.1 Status.........................................................................................................................................36
5.8.2 All Motors Power On ...............................................................................................................37
5.8.3 All Motors Power Off...............................................................................................................37
5.8.4 Transfer to On Line .................................................................................................................37
5.8.5 Transfer to Local ......................................................................................................................37
5.8.6 Reset ..........................................................................................................................................38
5.8.7 Get Controller Type and Configuration ................................................................................38
5.9 Remote Control Command Programming...................................................................................38
5.9.1 Preparing the Command Byte................................................................................................39
5.9.1.1 Encoding Filter Commands Into a Single Byte..............................................................39
5.9.1.2 Special Commands ............................................................................................................39
5.9.2 Command Transmission Protocol..........................................................................................39
5.9.2.1 Confirmation Command Echo .........................................................................................40
5.9.2.2 Command Completion Indicator .....................................................................................40

LAMBDA VF-5 OPERATION MANUAL – REV. 1.04A (20190606)
vii
6. OPERATIONS: EXTERNAL CONTROL: SERIAL RS-232 INTERFACE ................................41
6.1 Connecting to the Serial Port ........................................................................................................41
6.2 Input Command Set and Protocol ................................................................................................42
7. OPERATIONS: EXTERNAL CONTROL: USB INTERFACE....................................................43
7.1 Installing the Lambda VF-5 as a USB Device on a Windows System.......................................43
7.1.1 Installation Steps .....................................................................................................................43
7.1.2 Interactive USB Device Driver Installation..........................................................................45
7.2 Installing the USB Interface for Non-Windows Systems...........................................................47
7.3 Verifying USB Communication between Remote Computer and Lambda VF-5....................47
7.4 Uninstalling the USB Driver for the Lambda VF-5....................................................................49
7.5 Remote Commands and the USB Interface.................................................................................50
8. MAINTENANCE............................................................................................................................51
APPENDIX A. LIMITED WARRANTY............................................................................................53
APPENDIX B. ACCESSORIES .........................................................................................................55
B.1. VersaChrome® Filters..................................................................................................................55
B.2. Other Accessories ..........................................................................................................................55
APPENDIX C. FUSE REPLACEMENT...........................................................................................57
APPENDIX D. TECHNICAL SPECIFICATIONS ...........................................................................59
D.1. VF-5 Tunable Filterwheel............................................................................................................59
D.2. Controller.......................................................................................................................................59
APPENDIX F. EXTERNAL CONTROL COMMAND REFERENCE ............................................61
TABLE OF FIGURES
Figure 1-1 Anatomy of the Lambda VF-5 filter wheel. .......................................................................... 2
Figure 1-2. Lambda VF-5 Filter Wheel .................................................................................................... 4
Figure 1-3. Electrical connections............................................................................................................. 6
Figure 1-4. Lambda VF-5 front panel controls........................................................................................ 7
Figure 2-1. Schematic diagram of two possible experimental configurations. ..................................12
Figure 3-1. Lambda VF-5 Cabinet (rear view). ..................................................................................... 19
Figure 3-2. Switch, fuse, and power connection....................................................................................19
Figure 4-1. The Lambda VF-5 keypad for manual (local) control.......................................................24
Figure 6-1. Serial port pin assignments. ................................................................................................41
Figure 7-1 -- The USB cable device connector....................................................................................... 44
Figure 7-2 -- The Lambda VF-5 USB receptacle................................................................................... 44
Figure 7-3 -- Host connector end of USB cable. ....................................................................................44
Figure 7-4 -- USB host receptacle on remote computer. ...................................................................... 44
Figure 7-5 -- New USB device detected message box. ..........................................................................45

LAMBDA VF-5 OPERATION MANUAL – REV. 1.04A (20190606)
viii
Figure 7-6 -- Digital Signature dialog box.............................................................................................. 45
Figure 7-7 -- Specifying location of driver files...................................................................................... 46
Figure 7-8 -- Browsing for the driver file needed. ................................................................................. 47
Figure 7-9 -- USBTest main screen. ....................................................................................................... 48
Figure 8-1. Power entry module and fuse holder.................................................................................. 57
TABLE OF TABLES
Table 1-1. List of supported tunable filters.............................................................................................. 3
Table 4-1. Filter Switching Times (in milliseconds). ............................................................................27
Table 5-1. Remote Control Command Categories................................................................................. 29
Table 5-2. External control commands. .................................................................................................30
Table 5-3. Filter Command Structure....................................................................................................34
Table 5-4. Special command codes.......................................................................................................... 35
Table 5-5. Status Command Return Codes and Data...........................................................................36
Table 5-6. “Get Controller Type and Configuration” Command Return Codes and Data. .............38
Table 8-1. Controller Cables....................................................................................................................60
Table 8-2. Complete Command Reference............................................................................................. 61
Table 8-3. Filter command structure. ....................................................................................................64
Table 8-4. Status Command Return Codes and Data...........................................................................65
Table 8-5. “Get Controller Type and Configuration” Command Return Codes and Data. .............66

LAMBDA VF-5 OPERATION MANUAL – REV. 1.04A (20190606)
1
1. GENERAL INFORMATION
1.1 Introduction
The Lambda VF-5 is a filter wheel and shutter control system designed for rapid change and
aperture control of wavelength, and comprises a controller and a filter wheel that is placed in
the optical pathway(s) of your existing experimental setup. Next is a description on how this
manual is organized and the manner in which its use is intended, followed by a general and
functional description of the system.
1.1.1 How to Use this Manual
This manual is organized in a manner that is best suited for the typical manner in which the
reader would learn about the system, and then install, operate, and maintain it. Prior to the
table of contents of this manual is a series of cautionary and warning notes that should be
read first. This chapter (Chapter 1) provides an overall description of the system, leaving
more in-depth technical information towards the end of the chapter. The next chapter
describes how to install the system, followed by one or more chapters that provide operation
instructions, and ending with a chapter on maintenance. Following the final chapter are
several appendices that provide supplemental information. The installation chapter covers
everything related to installation, from unpacking the equipment as received, through to
ensuring that everything is correctly installed and is operating correctly. The operation
chapters cover the two basic types of user interaction with the system: Manual (local) control
and external computer control. Please take the time to read these instructions to assure the
safe and proper use of this instrument.
1.1.2 Technical Support
Unlimited technical support is provided by Sutter Instrument Company at no charge to our
customers. Our technical support staff is available between the hours of 8:00 AM and 5:00
PM (Pacific Time) at [phone]. You may also E-mail your queries to [e-mail].
1.2 General Description
The LAMBDA VF-5 is a microprocessor controlled, high-speed filter wheel designed for
microscopy and other applications that require rapid and accurate wavelength switching. The
Lambda VF-5 controller can control one filter wheel and features both USB and serial input
for remote control.
The VersaChrome filters from Semrock have excellent band-pass characteristics for which
Semrock is known, and the center wavelength can be tuned over a significant range by
adjusting the angle of incidence of the light. Sutter has combined this filter technology with
a mechanical system that allows a rapid selection of any center wavelength in the range of 5
filters. This device selects the correct filter and sets the required tilt to obtain the center
wavelength requested using a special version of the Sutter Lambda 10-B filter controller.
Control can be via the keypad, serial port input or USB input. Until a full manual is
produced this supplement will be used with the manual of the Lambda 10-B.
Each of the filters in the Versachrome line is designed to have the center wavelength of the
band pass selected by tilting the filter relative to the light path. It is well known that the

LAMBDA VF-5 OPERATION MANUAL – REV. 1.04A (20190606)
2
center wavelength of a band pass interference filter depends on the angle of incidence of
light, and this is sometimes used to make minor adjustments in wavelength. The coating
design of the Versachrome filters allows tilting up to 60 degrees without loss of the excellent
band pass characteristics so that the center wavelength can be shifted 60 to 100 nanometers.
(The amount of shift depends on the filter).
The maximum design angle for tilt is 60 degrees. As the tilt is increased the center
wavelength is shifted to shorter wavelengths but the width of the band pass does not change.
The relationship between angle and center wavelength is not linear. The first several degrees
of tilt have little effect, but the change is roughly 1 nm per degree of tilt as you approach the
maximum tilt. The required tilt angle for each nanometer has been programmed into the
microprocessor for each filter in the Versachrome series. If you specify a valid center
wavelength for one of the loaded filters the controller will automatically turn the wheel to
the correct filter and tilt the wheel to the appropriate angle.
If you prefer, you can instead specify the angle of tilt in steps of 0.225 degrees. The number of
steps must be in the range of 0 to 267. You can also directly select the filter to use. If you
select a combination of filter and angle that is used for a nanometer value command the
display will show the nanometer value. If the angle does not correspond exactly to a
programmed nanometer value for the current filter the controller will display the closest
whole nanometer wavelength with the ^ symbol to show that it is not the standard micro
step value for that wavelength.
The wheel has 5 positions for filters. In order to allow for possible future expansion the
standard Sutter 10 position filter commands have been used. As a result, the available filter
positions in this 5 position version have the values 0,2,4,6 and 8. The default position at
power on is filter 0 with a tilt of 0 degrees.
Figure 1-1 Anatomy of the Lambda VF-5 filter wheel.
The mechanical system has two step motor subsystems. One motor rotates the filter wheel so
that the desired filter is located in the optical path. The second motor rotates the entire

LAMBDA VF-5 OPERATION MANUAL – REV. 1.04A (20190606)
3
wheel subsystem in order to tilt the selected filter to the correct angle for the desired center
wavelength. Both subsystems have sensors for establishing the correct initial position and
verifying moves that are made in response to commands.
The following VersaChrome1tunable optical filters are available for use with the Lambda VF-
5:
Table 1-1. List of supported tunable filters.
Filter Type Wavelength Range Bandwidth Part Number
Tunable 338-380nm 16nm CO-O573380
Tunable 390-440nm 16nm CO-O573440
Tunable 440-490nm 15nm CO-O573490
Tunable 490-550nm 15nm CO-O573550
Tunable 550-620nm 14nm CO-O573620
Tunable 620-700nm 13nm CO-O573700
Tunable 700-800nm 12nm CO-O573800
The system is connected to the controller via a DB-25 connector. Although there is protection
against hot connection or disconnection of the cables it is important to avoid connection or
disconnection of these cables when the power is on.
At power on the tilt subsystem is rotated to 0 degrees, as indicated by an optical sensor. Once
the correct tilt is established the wheel rotates to the 0 filter position. The unit powers up in
the USB port mode. The local key can be used to select the manual mode, which allows
keypad control. Serial port control is normally established by sending the correct command
over the serial port, but can also be selected as the default mode using the keypad in the
manual mode. The display at power-on should be similar to the example below:
This display is an adaptation of the original 10B version that controls a filter wheel and
shutter. The direct control of the filter wheel in the VF-5 is identical to that of a Lambda 10
series filter wheel, so the top line, starting with W: for wheel, indicates that this is the 25 mm
aperture version, Filter 0 is selected, filter changing speed 1 (SP1) is selected, and the
controller is in the local mode (L). The power-on display will show a U for USB control. In
this case the LOCAL key was pressed to switch to the local mode.
The second line of the display indicates the current center wavelength selected in nm (WL-
380 nm). At power-on the indicated value should be equal to the center wavelength at a tilt
of 0 degrees for the filter loaded in filter position 0.
The selected speed for the tilt is also displayed (T3). The value following the T can be 0-3. As
with the filter wheel, 0 is the fastest speed.
The filters are installed oriented so that the best optical performance is obtained with light
directed into the optical port on the silver colored side of the housing and emerging from the
1VersaChrome®is a registered trademark of Semrock®
W: 25MM F0 SP1 L
S: WL-380 nm T3

LAMBDA VF-5 OPERATION MANUAL – REV. 1.04A (20190606)
4
optical port on the blue colored side of the housing. For best results the input light should be
well collimated. Light that is not well collimated will broaden the bandpass of the filters.
The controller can run the filter wheel under remote control through a USB or serial input
using the same simple protocol as the original Lambda 10-B controller with some differences
in commands. The USB port uses a command set similar to the serial input. Some important
considerations about using a combination of input sources (e.g., the keypad and the Serial
port) are discussed in the Operations – External Control section of this manual.
The following instructions are meant to help you set up the Lambda VF-5 and familiarize you
with the manual mode of filter selection. More detail on controller functionality, filter
installation and remote communications can be found in other sections of this manual.
The following instructions are meant to help you set up the Lambda VF-5 and become
familiar with the manual mode of filter selection. Further details on controller functionality
and remote communications can be found in other sections of this manual.
1.2.1 Systems
1.3 Filter Wheel
1.3.1 Mechanical Description
The basic components of the filter wheel mechanical assembly are shown below in the
following two figures. The only components that are to be removed by the user are the drop-
in or slide-in filter holders and the plug in the loading port. At no time should the user
remove the cover plate from the wheel housing.
Figure 1-2. Lambda VF-5 Filter Wheel
1.3.2 Filter Wheels
Description. Note that you must only use filter wheels manufactured by Sutter Instrument
Company. All filter wheel options are listed in Sutter Instrument’s catalogue and web site
(http://www.sutter.com), and in the following list.
5-position VersaChrome filter
LBVF-5(?).

LAMBDA VF-5 OPERATION MANUAL – REV. 1.04A (20190606)
5
wheel
1.3.2.1 Mechanical Description
The basic components of the filter wheel mechanical assembly are shown in following figures.
The only components that are to be removed by the user are the drop-in or slide-in filter
holders and the plug in the loading port.
1.3.3 Filter Wheel Adapters
Most microscopes, cameras, light sources and other optical instruments to which the Lambda
VF-5 Filter Wheel may be interfaced will require some sort of adapter to link the devices.
Adapters for interfacing the Filter Wheel to most instruments are available from Sutter
Instrument Company or can be custom built by Sutter. Suitable adapters are available from
other sources, as well, but Sutter Instrument Company assumes no responsibility for the
performance, suitability and safety of adapters built by the user or other manufacturers.
1.3.4 Cables
1.4 Controller
1.4.1 Principles of Operation
The Lambda VF-5 controller can be operated locally (manually) from the controller keypad or
remotely from a computer through either the parallel or serial port. These three operational
modes (manual, USB and serial) are functionally identical. Each allows the user to select:
Filter position
Filter switching speed
Filter angle
The remainder of this chapter provides a detailed description of the controller’s rear panel
connectors and front panel controls. Information needed to connect the power cord and filter
wheel(s) is found in the FIRST TIME USE chapter. Instructions on operation of the
controller and manual keypad control of the filter wheel(s) are presented in the MANUAL
CONTROL chapter. The REMOTE CONTROL chapter explains control of the unit from a
remote device, as well as supplying some technical details relevant to local operation.
Technical details, which are not required for operation but which may help you understand
the behavior of the unit, are found in APPENDIX A: Stepping Motor Operation.
1.4.2 Rear Panel Connectors
All electrical connections are all made on the rear panel of the Lambda VF-5. See the FIRST
TIME USE chapter for details on connecting the power cord and filter wheel cable(s).

LAMBDA VF-5 OPERATION MANUAL – REV. 1.04A (20190606)
6
Figure 1-3. Electrical connections.
FILTER WHEEL POSITION AND ANGLE CONTROL – A 25 pin, DSUB connector used to
link the Lambda VF-5 controller with the VF-5 filter wheel.
USB PORT – A USB Type B receptacle used to connect the Lambda VF-5 controller as a USB
device to a USB port of a host computer.
SERIAL PORT – A 9 pin, DSUB connector used for establishing a serial interface between
the Lambda VF-5 and a remote device (computer) using the cable provided. This cable should
not be used simultaneously with the parallel port cable.
POWER SWITCH – This turns on the system power.
LINE POWER – This socket is used to connect the power cord to the Lambda VF-5.
FUSE LABEL – Information found here includes the model number of this instrument,
appropriate supply voltage and the type of fuse required for the supply voltage.
FUSE – Fuse compartment containing the supply voltage fuse and an extra fuse. Replace
blown fuses with a fuse of the appropriate value as given on the fuse label (back panel of the
controller) or on the TECHNICAL SPECIFICATIONS page in this manual.
Not used
Not used
Not used
Connects to
VF
-5 filter
wheel
USB or serial
for external
control
Power switch,
fuse, & cable
receptacle

LAMBDA VF-5 OPERATION MANUAL – REV. 1.04A (20190606)
7
1.4.3 Front Panel Controls
Figure 1-4. Lambda VF-5 front panel controls.
1.4.3.1 Keypad
There are 16 keys on the Lambda VF-5 keypad.
Numerical keys 0 through 9: These keys are used to manually select filter positions and,
with the # key, to choose between the eight pre-set speeds
LOCAL: Takes the controller off-line
ON LINE: Puts the controller on-line
F1: Go to main menu.
F2: Used as “Enter” for neutral density shutter steps.>
SPEED: This key is used to access the rotational speed selection mode. When followed by the
λkey, the tilt speed selection mode is accessed.
λ: Used for switching to specified wavelengths.
Keys are read while depressed but the appropriate action will occur only when the key is
released. If a key is pressed while a move is in progress but released after the move is over,
the key will read normally. Keys pressed and released while a move is in progress are ignored.

LAMBDA VF-5 OPERATION MANUAL – REV. 1.04A (20190606)
8
1.4.3.2 Display
After the copyright screen, the unit display should be similar to the following if the controller
has already been initialized with the base wavelength of each variable filter installed on the
filter wheel.
The start menu shown
If the Lambda VF-5 controller has not been initialized for the first time or if the controller
has been reset, the following screen will display for about 5 seconds,
... and then the following menu is displayed.
Please refer to the Initialization section in the Installation chapter for instructions on how to
initialize the Lambda VF-5 controller for the specific set of variable filters mounted on the
filter wheel that is now attached to the controller. Once the controller has been properly
initialized, the controller will display the standard top-level start menu after the unit has
been powered up and the copyright and firmware version screen has been displayed.
1.6 Functional Description
1.6.1 Stepping Motor Operation
Stepping motors are not as familiar to most people as the common DC motor, but there are
some similarities. The DC motor consists of an armature, an electromagnet mounted on a
rotating shaft, which is located inside a permanent magnet. Current is supplied to the
electromagnet through brushes that rub on contacts on the armature. When the
COPYRIGHT SUTTER
INSTRUMENT v3.16
W: 25MM F0 SP3 U
S: WL-490 nm
W: 25MM F0 SP3 L
S: WL-490 nm
ENTER FILTER POS
NO. 0-9 FOR VF..
F1-BROWSE 999-*
F2-ENT 000-EXIT

LAMBDA VF-5 OPERATION MANUAL – REV. 1.04A (20190606)
9
electromagnet is energized, the armature rotates to align the poles of the electromagnet with
the opposite poles of the permanent magnet. Of course, before this can occur, the rotation of
the armature changes the contact plates rubbing on the brushes so that the current is
reversed. This causes the poles of the electromagnet to reverse, establishing a force for
continued rotation. This switching action is called commutation.
In a stepping motor, the rotating element, called a rotor, is generally a permanent magnet
while the fixed element, the stator, is the electromagnet. The key difference between stepping
motors and DC motors, however, is the method of commutation. The DC motor commutates
automatically as it rotates. Thus the timing of the commutation is determined by the speed
of rotation, which may vary with the load or applied power. The commutation of the stepping
motor is set by external electronics, forcing the motor to rotate at a predetermined rate. If
the load is such that the motor does not have the force to produce the correct rate of rotation,
the rotation will become erratic and may even reverse.
The force exerted between two magnet poles is proportional to the square of the distance
between the poles. A motor with a single electromagnet and only two poles would exhibit
considerable loss of power when the distance between the poles of the permanent magnet and
the electromagnet was greatest. It is understandable that, in most practical DC motors, the
armature has more than 2 poles. This allows the commutation to occur over a smaller angle
of rotation, so that the active poles can always be relatively close to the poles of the
permanent magnet.
Stepping motors are also made with multiple poles on both the rotor and stator; the exact
arrangement determines the number of steps per revolution. The motor used in the
LAMBDA VF-5 has 200 steps per revolution (1.8 degrees per step). There are usually two
windings in the stator, and reversing the current on one of the windings produces a single
step of rotation. Reversing the current on the second winding will then produce another step.
If the first winding is then reversed again, returning to its original value, a third step will
result. Finally, reversing the second winding, so that both windings are back to their original
state, will produce a fourth step. This pattern may then be repeated to continue rotation in
the same direction. Reversing the sequence produces steps of rotation in the opposite
direction.
The rate and distance of rotation is determined by the rate and number of commutation
steps. As long as the current is held constant in both windings, the rotor will not rotate. This
makes the stepping motor ideal for producing fast start and stop movements. Some
limitations should be considered: Given that there are only four states of the control
electronics (2 polarities for each of the 2 windings) but 200 steps per revolution, it follows
that, for each of these 4 states, there are 50 possible rotary positions. In order to establish
the absolute position an external sensor must be added. Absolute position only needs to be
determined once so long as the subsequent moves occur without errors.
Correct operation of stepping motors, which is outlined above, is not always obtained. If the
motor lacks the torque to accelerate and decelerate the load at the rate indicated by the
control electronics, the resulting move may differ from that commanded by the control
electronics. For instance, if enough external force is applied, the motor shaft may be rotated
even though the command signal has not changed. For small rotations (less than 3.6
degrees), the motor shaft will return to the correct position if the force is removed. For larger
rotations, the shaft will stop at the nearest of the 50 correct positions for that command
signal when the external force is removed.

LAMBDA VF-5 OPERATION MANUAL – REV. 1.04A (20190606)
10