THORLABS MC1000A User manual

PO Box 366, 435 Route 206N, Newton NJ 07860
Ph: [phone], Fax: [phone], Web: www.thorlabs.com
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MC1000A Optical Chopper
Operating Manual
Related Products
Model Description
MC1F2 2-slot Replacement Blade, 1 – 99Hz
MC1F10 10-slot Replacement Blade, 25 – 1kHz
MC1F15 15-slot Replacement Blade, 38 – 1.5kHz
MC1F30 30-slot Replacement Blade, 75 – 3kHz
MC1F60 60-slot Replacement Blade, 150 – 6kHz
MC2F57 Dual Slot (5 Inner / 7 Outer)
Replacement Blade
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Table of Contents
MC1000A Optical Chopper ................................................................................................................................................. 1
OPERATING MANUAL.............................................................................................................................................................. 1
TABLE OF CONTENTS ......................................................................................................................................................... 1
TABLE OF CONTENTS ......................................................................................................................................................... 2
WEEE...................................................................................................................................................................................... 4
SECTION 1: SAFETY WARNINGS........................................................................................................................................ 5
SECTION 2: SPECIFICATIONS............................................................................................................................................. 6
2.1 PHYSICAL FEATURES:...................................................................................................................................................... 6
2.2 POWER SUPPLY:.............................................................................................................................................................. 6
2.3 INPUT /OUTPUT SPECIFICATIONS:..................................................................................................................................... 6
2.4 PERFORMANCE SPECIFICATIONS:...................................................................................................................................... 6
2.5 COMMUNICATIONS:.......................................................................................................................................................... 7
2.6 OPTICAL HEAD SPECIFICATIONS:...................................................................................................................................... 7
2.7 BLADE SPECIFICATIONS:................................................................................................................................................... 7
SECTION 3: DESCRIPTION .................................................................................................................................................. 8
SECTION 4: PARTS LIST ...................................................................................................................................................... 8
SECTION 5: FUSE REPLACEMENT / LINE VOLTAGE SELECTION ................................................................................. 9
5.1 MATERIALS NEEDED......................................................................................................................................................... 9
5.2 FUSE REPLACEMENT AND LINE VOLTAGE SELECTION ........................................................................................................ 9
SECTION 6: GETTING STARTED QUICKLY...................................................................................................................... 10
6.1 SETUP ........................................................................................................................................................................... 10
6.2 INTERNAL REFERENCE OPERATING MODE....................................................................................................................... 10
6.3 EXTERNAL REFERENCE MODE ........................................................................................................................................ 10
SECTION 7: DESCRIPTION ................................................................................................................................................ 11
7.1 CONTROLLER FRONT PANEL FEATURES .......................................................................................................................... 11
7.2 CONTROLLER REAR PANEL FEATURES ............................................................................................................................ 12
7.3 OPTICAL HEAD............................................................................................................................................................... 13
SECTION 8: OPERATING INSTRUCTIONS ....................................................................................................................... 14
8.1 INTERNAL FREQUENCY SYNTHESIZER ............................................................................................................................. 14
8.1.1 Setup for Internal Reference Frequency .................................................................................................................................14
8.1.2 Selecting the REFERENCE OUT signal .................................................................................................................................14
8.1.3 Why doesn’t the motor speed exactly match the set speed? ....................................................................................................14
8.2 EXTERNAL REFERENCE MODE ........................................................................................................................................ 14
8.2.1 Setup for External Reference Frequency ................................................................................................................................15
8.2.2 Selecting the REFERENCE OUT signal .................................................................................................................................15
8.3 HARMONIC REFERENCE GENERATION ............................................................................................................................. 15

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8.3.1 Setting the Reference Harmonic..............................................................................................................................................15
8.3.2 Setting the Sub-Harmonic .......................................................................................................................................................15
8.3.3 Combining the Harmonic and Sub-Harmonic Modes.............................................................................................................15
8.4 2-FREQUENCY CHOPPING .............................................................................................................................................. 15
8.4.1 Setting the Chopping Speed in the 2-Frequency Mode ........................................................................................................... 16
8.5 SETTING THE CHOPPER BLADE ....................................................................................................................................... 16
8.6 2-SLOT BLADE ............................................................................................................................................................... 16
SECTION 9: SERIAL PORT................................................................................................................................................. 17
9.1 SERIAL PORT PARAMETERS............................................................................................................................................ 17
9.2 SERIAL PORT PIN OUTS ................................................................................................................................................. 17
9.3 SERIAL INTERFACE COMMAND SCREEN........................................................................................................................... 17
9.4 SERIAL COMMAND SUMMARY ......................................................................................................................................... 18
SECTION 10: MAINTENANCE AND TROUBLESHOOTING.............................................................................................. 19
10.1 CLEANING.................................................................................................................................................................... 19
10.2 DIAGNOSTIC MESSAGES............................................................................................................................................... 19
SECTION 11: CONTACTS ................................................................................................................................................... 19
USA, CANADA,AND SOUTH AMERICA ................................................................................................................................... 19
EUROPE .............................................................................................................................................................................. 19
JAPAN AND ASIA .................................................................................................................................................................. 19
APPENDIX A: CERTIFICATIONS AND COMPLIANCES ................................................................................................... 20

WEEE
As required by the WEEE (Waste Electrical and Electronic Equipment Directive) of the European Community and the
corresponding national laws, Thorlabs offers all end users in the EC the possibility to return “end of life” units without incurring
disposal charges.
This offer is valid for Thorlabs electrical and electronic equipment
•sold after August 13th 2005
•marked correspondingly with the crossed out “wheelie bin” logo (see fig. 1)
•sold to a company or institute within the EC
•currently owned by a company or institute within the EC
•still complete, not disassembled and not contaminated
As the WEEE directive applies to self contained operational electrical and electronic products, this “end of life” take back
service does not refer to other Thorlabs products, such as
•pure OEM products, that means assemblies to be built into a unit by the user (e. g. OEM laser driver cards)
•components
•mechanics and optics
•left over parts of units disassembled by the user (PCB’s, housings etc.).
If you wish to return a Thorlabs unit for waste recovery, please contact Thorlabs or your nearest dealer for further
information.
Waste treatment on your own responsibility
If you do not return an “end of life” unit to Thorlabs, you must hand it to a company specialized in waste recovery. Do not dispose
of the unit in a litter bin or at a public waste disposal site.
Ecological background
It is well known that WEEE pollutes the environment by releasing toxic products during decomposition. The aim of the
European RoHS directive is to reduce the content of toxic substances in electronic products in the future.
The intent of the WEEE directive is to enforce the recycling of WEEE. A controlled recycling of end of live products will
thereby avoid negative impacts on the environment.
Crossed out “wheelie bin” symbol
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Section 1: Safety Warnings
WARNING: TO AVOID ELECTRICAL SHOCK THE POWER CORD PROTECTIVE GROUNDING
CONDUCTOR MUST BE CONNECTED TO GROUND. REFER SERVICING TO QUALIFIED
PERSONEL.
Thorlabs provides the proper power input cable with each MC1000A for use in the United States. If using this unit
anywhere else, the user will need to supply a properly grounded power cable to power the unit. If something should go
wrong with the unit, do not attempt to fix. Call a Thorlabs representative and arrange for repair. The unit should never be
opened unless changing the fuse or line voltage as described in Section 5.
WARNING: THE UNIT MUST BE POWERED OFF, UNPLUGGED FROM THE AC INPUT POWER
SOURCE, AND DISCONNECTED FROM ALL EXTERNAL DEVICES BEFORE REMOVING THE
COVER AND REPLACING THE FUSE. FAILURE TO DO SO MAY CAUSE SERIOUS INJURY TO
THE USER SINCE HIGH VOLTAGES EXIST WITHIN THE UNIT.
Thorlabs ships all units configured to operate in the United States (i.e. line voltage 115VAC, 60Hz and 250mA fuse
installed). It may be necessary to change the line voltage to 230VAC and replace the fuse with a 125mA Slow Blo fuse.
Care must be taken when configuring the unit. See Section 5 for complete details.
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WARNING: ROTATING BLADE. KEEP HANDS CLEAR WHILE THE BLADE IS SPINNING. TURN
POWER OFF BEFORE SERVICING.

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Section 2: Specifications
2.1 Physical Features:
Dimensions (W x H x D): 5.8” x 2.8” x 12.5” (147mm x 71mm x 317.5mm)
Input and Output Connectors: BNC’s
Frequency Control: Up / Down Keypad Switches
Mode Control: Keypad Switch with LED Illuminated Selection
External Control: Keypad Switch Enable with LED indication
Input Power Connection1: IEC Connector w/ US style power cord
Weight: 5 lbs (9.1 lbs shipped weight)
Operating Temperature: 10 - 40°C
Display Type: Green LED Segments
No of Digits: 4
Frequency Resolution: 1Hz (10, 15, 30, 60 and 2f blades)
0.01Hz (2 slot blade)
2.2 Power Supply:
Supply Type: Linear
Voltage Selection: Switch Selectable between 115 / 230 VAC
Input Voltage: 100/115VAC +/-10%, 230VAC +/- 10%
Line Frequency: 50 – 60Hz
Input Power: 20VA max
Fuse Ratings: 250mA @ 115VAC
125mA @ 230VAC
Fuse Type: IEC60127-2/III (250V, Slow Blow Type ‘T’)
Fuse Size: 5 x 20mm
2.3 Input / Output Specifications:
Ext. Input Compatibility: TTL/CMOS
Ext. Input Voltage Range2: 0 – 5V
Input High >2V
Input Low <0.8V
Ext. Input Impedance: 200Ω
Ref Out Compatibility: TTL/CMOS
Ref Out Voltage Range2: 0 – 5V typ.
Ref Out Impedance: 200Ω
Min Load Impedance3: 500Ω
Ref Out Signals: Chopping Blade, Synthesizer, Sum and Diff Frequencies
Ref Out Selection: ‘Mode’ Keypad selection or RS232 command ‘O’
2.4 Performance Specifications:
Chopping Frequency:
MC1F2 (2 slot): 1 – 99Hz
MC1F10 (10 slot) 20 – 1kHz (Default Blade)
MC1F15 (15 slot) 30 – 1.5kHz
MC1F30 (30 slot) 60 – 3kHz
MC1F60 (60 slot) 120 – 6kHz
MC2F57 (2f slot) 14 – 700Hz (Outer)
10 – 500Hz (Inner)
Phase Jitter (@ max freq):
MC1F2 (2 slot): 0.05°rms max
MC1F10 (10 slot) 0.42°rms (0.13°rms typ.) (Default Blade)
MC1F15 (15 slot) 0.68°rms (0.27°rms typ.)

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MC1F30 (30 slot) 1.10°rms (0.45°rms typ.)
MC1F60 (60 slot) 1.10°rms (0.78°rms typ.)
MC2F57 (2f slot) 0.38°rms (0.08°rms typ.)
Frequency Drift: <20 ppm / °C
Chopping Range:
Harmonic: 2x to 15x
Sub-Harmonic: 1/2x to 1/15x
2.5 Communications:
Communications Port: RS232
Com Connection: DB9 Female
Required Cable5: DB9 Male to Female
Protocol:
Baud Rate: 19,200 (fixed)
Data Bits: 8
Stop Bits: 1
Parity: None
Handshaking: None
2.6 Optical Head Specifications:
Chopping Blade Diameter: φ4.0” (φ101.6mm)
Chopping Blade Thickness: 0.010” (0.254mm)
Mounting Base: ¼”-20 (or M8) clearance slots spaced 2.0”
(Compatible with Thorlabs 1” breadboard spacing)
Mounting Hole: ¼”-20 with ¼” max screw depth
2.7 Blade Specifications:
Chopping Blade Slots4:
MC1F2: 2
MC1F10: 10 (Default Blade)
MC1F15: 15
MC1F30: 30
MC1F60: 60
MC2F57: 7 Outer, 5 Inner
Slot Angle:
MC1F2: 180°
MC1F10: 36°(Default Blade)
MC1F15: 24°
MC1F30: 12°
MC1F60: 6°
MC2F57: 51.4°Outer, 72°Inner
Notes:
1. The MC1000A is supplied with a US style power cord. Units purchased in other countries must supply their own certified rated power cord.
2. The reference output and external input is short circuit protected by limiting the current to 25mA. Over and Under voltage protection is
available, but continued use will degrade or damage the unit.
3. The Min Load Impedance represents the smallest allowable terminating resistance. Applying lower impedances will cause the short circuit
protection to limit the output voltage. Continued use in this mode will cause circuit degradation and eventual circuit failure.
4. The MC1F10 blade is supplied with the unit. All other blades specified may be purchased separately through Thorlabs, Inc.
5. Do not use a null modem cable.

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Section 3: Description
The MC1000A Optical Chopper is a precision instrument utilizing advanced features to meet the most demanding applications.
The MC1000A uses a phased-lock loop (PLL) motor speed control design to precisely lock the chopping speed and phase to a
reference signal. An internal, crystal-stabilized frequency synthesizer provides an accurate and stable reference frequency for
ultra-low long-term frequency drift.
Unlike conventional, open-loop speed control designs, the PLL speed control circuit also allows the MC1000A chopper to be
synchronized to external reference signals, including other MC1000A choppers and reference sources such as DSP lock-in
amplifiers.
For more advanced measurements, the MC1000A can lock to a harmonic, sub-harmonic, or fractional-harmonic of an external
reference frequency. A second PLL circuit is used to multiply the external reference up to the 15th harmonic. This multiplier is
followed by a digital divider to divide the reference down to the 15th sub-harmonic. By combining both the frequency multiplication
and division together, a fractional harmonic can be obtained.
The MC1000A also supports 2-frequency chopping from a single chopper blade. A special blade is available with 7 outer slots
and 5 inner slots. This slot combination allows a single beam to be split and individually modulated for ratio metric experiments.
Other applications include pump-probe experiments where the pump beam is modulated at the outer frequency while modulating
a probe beam at the inner frequency. The MC1000A provides the sum and difference frequencies of the 2-frequency blade for
accurate lock-in detection of the frequency-mixed response.
A high quality, Swiss-made, rare earth magnet DC motor and a photo-etched chopper optical wheel drive the precision. The
compact optical head has a wide base for extra stability. The base is slotted for two ¼-20 mounting screws on 2” centers. The
interface cable uses standard RJ-45 modular connectors for easy setup.
The MC1000A controller includes a large, 4-digit, easy to read LED display for monitoring the chopper frequency. All of the
operating modes are accessible from streamlined, front panel push-button controls. Multiple user setups can be easily saved and
recalled from non-volatile memory. An RS-232 serial interface is included as a standard feature for remote interfacing the
MC1000A to other equipment.
Thorlabs offers a number of different blades to extend the range of the chopping frequency. A standard 10-slot blade is
included with the MC1000A. Two slot, 15 slot, 30 slot, 60 slot and the 2-frequency blades are also available.
Section 4: Parts List
Below is a list of all components shipped with the MC1000A Optical Chopper.
MC1000A Control Box
MC1000A Optical Chopping Head
MC1F10: 10-slot chopping blade
2 meter RJ-45 cable for optical head / control box interface
Operating Manual
US Power Supply Line Cord
125mA Fuse for use at 230VAC operation (250mA fuse installed in unit)
1/16” Allen Key for blade replacement
0.05” Allen Key for hub alignment.
(3X) 4-40 x 1/8” Phillips Pan Head Screws with Internal Tooth Washers
The following items are sold separately:
MC1F2: Two Slot Replacement Blade, 1 – 99Hz
MC1F15: 15-slot Replacement Blade, 38 – 1.5kHz
MC1F30: 30-slot Replacement Blade, 75 – 3kHz
MC1F60: 60-slot Replacement Blade, 150 – 6kHz
MC2F57: Dual Slot (5 Inner / 7 Outer) Replacement Blade

Section 5: Fuse Replacement / Line Voltage Selection
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line voltage if n
Thorlabs ships it MC1000A units configure to operate at 115VAC. The line voltage and installed fuse must be changed to
operate this unit at 230VAC. To operate at 100VAC, use the 115VAC setting. Follow the instructions below to change the
ecessary.
WARNING: THE UNIT MUST BE POWERED OFF, UNPLUGGED FROM THE AC INPUT POWER
SOURCE, AND DISCONNECTED FROM ALL EXTERNAL DEVICES BEFORE REMOVING THE COVER
AND REPLACING THE FUSE. FAILURE TO DO SO MAY CAUSE SERIOUS INJURY TO THE USER
SINCE HIGH VOLTAGES EXIST WITHIN THE UNIT.
5.1 Materials Needed
MC1000A Operating Manual – The most recent version of this operating manual will be available on Thorlabs
web site.
125mA Type IEC60127-2/III – (Type ‘T’ Slow Blow Fuse) The 125mA fuse is required for 230V operation only.
Thorlabs supplies a 125mA fuse with all of its MC1000A units and must be installed when operating at 230VAC.
250mA Type IEC60127-2/III – (Type ‘T’ Slow Blow Fuse) The 250mA fuse is installed from the factory. This must
be installed when operating the unit at 100 / 115VAC.
Phillips Head Screwdriver (#2 Preferred) – We do not recommend using electrically powered screwdrivers.
5.2 Fuse Replacement and Line Voltage Selection
1. Important – Disconnect the optical head and any external devices from the MC1000A BNC’s.
2. Important – Disconnect the power cord. Do not open the unit if the power cord is connected. See warning
above.
3. Remove the two screws securing the enclosure cover with a Phillips head screwdriver. The screws are located on
the bottom side, rear corners of the unit. Do not lose the screws.
4. Carefully remove the cover by sliding toward the rear of the unit.
5. To change the line voltage, locate the line select switch behind the power switch. Select the appropriate line
voltage by adjusting the switch to either 110 or 220. Select 110 if operating at 100VAC to 120VAC. Select 220 for
operation from 220VAC to 240VAC.
6. Replace the enclosure cover and secure with the enclosure screws.
7. Remove the line voltage selection screw and reinstall in the appropriate location. See page 11, Figure 2 for
details.
8. Locate the fuse holder below the power input connector. Slide the fuse tray out using a flat head screwdriver.
Remove the fuse and replace with the appropriate value as described below:
100 – 120VAC operation – Use the 250mA Type IEC60127-2/III (5x20mm, 250V, Slow Blow Type ‘T’)
220 – 240VAC operation – Use the 125mA Type IEC60127-2/III (5x20mm, 250V, Slow Blow Type ‘T’)

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Section 6: Getting Started Quickly
This section is provided for those interested in getting the MC1000A up and running quickly as a basic optical chopper.
The more advanced features are described in detail in the following sections.
6.1 Setup
1. Carefully unpack the MC1000A controller, optical head, and accessories. See section 4 for a complete list of
parts. If any of the items appear damaged or missing, do not use the MC1000A. Call Thorlabs, or email
[email protected] and arrange for a replacement.
2. Remove the 3 mounting screws and lock washers from the chopper blade hub using the 1/16” hex key (provided).
3. Unpack the 10-slot blade and install onto chopper blade hub using the 3 screws and washers removed in the
previous step. Tighten the screws securely with the hex wrench.
4. Attach the modular cord into the jack labeled ‘OPTICAL HEAD’ on the back of the MC1000A controller and plug
the other end into modular jack on the optical head.
5. Mount the optical head on a sturdy surface and check that the blade can spin free of any obstruction.
6. Attach the AC line cord to the MC1000A and plug into an AC outlet.
Note: the MC1000A can be operated from 100/115VAC or 230VAC. A voltage selector switch is located inside of the
MC1000A controller. If you are not sure what operating voltage your unit is set to, proceed immediately to Section 5.0 for
instructions on setting the operating voltage.
6.2 Internal Reference Operating Mode
This MC1000A is most commonly used in the internal reference mode. The chopping speed is set by the internal crystal-
stabilized frequency synthesizer.
1. Turn the MC1000A power on. The LED display will go through a startup sequence: first, all of the display
segments and LED’s are lit, then the firmware rev level is displayed, followed by the current blade setting.
2. The display should show “b 10” for the 10-slot blade. If not, press the ‘▲’ key until the “b 10” message is
displayed and then release the button. The unit will time out after a second or two and go into a standby mode
with the display showing “oFF”. If you miss the timing of this, turn the power switch off then back on again to
return to this mode.
3. If the unit comes up in the EXTERNAL REFERENCE Mode (as indicated by the LED above the ‘EXT IN ENABLE’
key being lit), press the ‘EXT IN ENABLE’ key to turn it off and return to the internal reference mode.
4. The unit should be in a standby mode with “oFF” displayed on the front panel. Press any of the keys to start the
chopper motor.
5. To change the chopper speed, press the ‘▲’ or ‘▼’ keys until the desired speed is shown. Release the key and
the unit will adjust its speed and lock onto the set speed within a few seconds.
6.3 External Reference Mode
This mode is very similar to the internal reference mode except that the chopper blade is locked to a logic-level external
reference signal.
1. To enable external reference mode, attach a TTL or CMOS logic level reference signal to the ‘EXT REF INPUT’
BNC on the front panel and follow the above steps.
2. Press the ‘EXT IN ENABLE’ key to enable the external reference mode.
Note: If the chopper does not lock to the exactly frequency of the external signal check that the harmonic multiplier, N, is
set to 1 by pressing the ‘MODE’ key until the light under the ‘SET N’ LED is lit. The display should show a 1. If not, press
the ‘▼’ key until it reaches 1. Repeat his step for the sub-harmonic divider, D.