OPTOGAMA LPA-A v2 Series User manual

!
MANUAL v2.2
LPA-A
ADVANCED and INTEGRATED
MOTORISED LASER
POWER ATTENUATOR
LPA-A v2 series
KEY for DISCOVERIES

Table of contents"
Table of contents#2"....................................................................................................................................
1. Safety requirements#4"...........................................................................................................................
2. Operation principle#5".............................................................................................................................
2.1.Contrast improvement. Angle adjustment!5.....................................................................................................................
2.2.Features and advantages!5..............................................................................................................................................
2.3.Optical design!5...............................................................................................................................................................
3. Product description#6"............................................................................................................................
3.1.Optical specifications!6....................................................................................................................................................
3.2.Mechanical specifications!6.............................................................................................................................................
3.3.Electronic specifications!6................................................................................................................................................
3.4.Conditions!6....................................................................................................................................................................
3.5.Controller!7......................................................................................................................................................................
3.5.1.Interfaces, pinout!7..................................................................................................................................................
3.6.Voltage levels!7................................................................................................................................................................
3.7.What’s in the box?!7........................................................................................................................................................
3.8.Available accessories!7....................................................................................................................................................
4. Software#8".............................................................................................................................................
4.1.Minimum Hardware requirements (recommended)!8........................................................................................................
4.2.System requirements!8....................................................................................................................................................
4.3.Supported client operating systems!8..............................................................................................................................
4.4.Installing the software!8...................................................................................................................................................
4.5.Using the software!10......................................................................................................................................................
4.5.1.Connection, device selector!10.....................................................................................................................................
4.5.2.Settings, calibration!10.................................................................................................................................................
4.5.3.Main window!11...........................................................................................................................................................
4.6.Updating the firmware!12................................................................................................................................................
5. Commands#13"......................................................................................................................................
5.1.Interface!13.....................................................................................................................................................................
5.2.Description!13.................................................................................................................................................................
5.3.Serial communication example in Python!15....................................................................................................................
6. Technical drawings#16...........................................................................................................................
2

LPA-A v2
Advanced & Integrated
Motorised laser power attenuator
Congratulations on your purchase of the advanced
motorised laser power attenuator from Optogama, UAB.
***
September 2019
Copyright UAB Optogama. All rights reserved.
No part of this manual may be reproduced, transmitted in
any form without the permission of Optogama.
Claims will not be accepted and warranty repair will not be
carried out in case of improper use, incorrect service and
maintenance not according to product instructions.
Warranty claim shall not be accepted if there are any signs
of:
•Non-authorised alteration
•Disassembling of the device
•Mechanical or any external damage
•If warranty term has expired
•Serial number of the product is missing
Symbols"
CAUTION!
Sections marked with this symbol indicate dangerous
situations that can result in damage to the device,
components connected to it or operator.
NOTE:
Sections marked with this symbol indicate important
information on laser power attenuator or about this manual.
Due to constant development of our products we reserve
the right to make changes in the production line without
further notice. Up-to-date information is available at our
website www.optogama.com. If there are any further
questions, please contact us.
Optogama is not liable for damage or injury resulting directly
or indirectly from use of this product for anything other than
its intended purpose.
The motorised laser power attenuator is intended for
industrial and scientific use only. If there are any other
electrical devices connected to or used in conjunction with
the laser power attenuator, all legal regulations and technical
standards that are applied to those devices must be
observed as well.
For any technical assistance and consultation please
contact your local dealer or directly [email protected].
3

1. Safety requirements"
•All safety instructions must be followed.
•All rules and regulations concerning the safe operation of
lasers must be known and applied while installing and
operating motorised laser power attenuator.
•Even when wearing safety glasses avoid eye contact
with direct or scattered laser light while assembling,
installing and operating the device.
•The device should never be exposed to dirt, dust or
moisture.
•Before any operation make sure the device is installed
correctly and well adjusted and all cover stickers are
removed.
•Protective measures should be considered if necessary.
•Electrical safety requirements must be complied while
operating this device.
CAUTION! High laser output power may damage or destroy
optical elements.
CAUTION! The device is meant to be used with a
collimated beam. Users take full responsibility when using
the device with a highly converging beam.
CAUTION! Before increasing laser power make sure the
device is aligned and there is no beam cut. It may damage
optical elements.
4
INPUT
COVER STICKERS MUST $
BE REMOVED BEFORE USE
OUTPUT$
P-pol
!
!
REFLECTED
BEAM$
S-pol
Or absorbed
by beam
dump

2. Operation principle"
LPA-A consists of zero-order half-waveplate and High
contrast Brewster type thin film polariser.
Zero-order half-waveplate rotates the polarisation. Brewster
type thin polariser passes P-polarised and reflects the S-
polarised laser beam. Waveplate and polariser are coated
for the desired wavelength. The attenuation adjustment is
achieved by motorised rotating of the waveplate, which is
located in the incident of the laser beam. The attenuation
level is controlled by the software in 0.1-98% range.
NOTE: Before use calibration is required
CAUTION! Before increasing laser power make sure the
device is aligned and there is no beam cut. It may damage
optical elements.
2.1.Contrast improvement. Angle
adjustment"
Incident light’s angle αshould be adjusted to improve device
contrast (± 2 deg maximum). Use HEX 1,5 key.
• Clock-wise to decrease angle
• Counter clock-wise to increase angle
Fig 2. Schematic explanation of optical design of laser power attenuator
(LPA-A)
2.2. Features and advantages"
• Integrated controller"
• Absolute position encoder - no homing required
• High accuracy - ±0.005 deg
(less than ±0.01% of laser power)
• Resolution - 0.002 deg, 7.2 arcsec, 0.035 mrad
• Robust design
• Clear aperture - ø15 mm"
• Fast adjustment - less than 0.2 sec (min to max)
• High damage threshold:
up to 10J/cm2 (10 ns @ 1064 nm)
• Adjustable polariser angle
2.3.Optical design"
LPA-A optical elements are coated for high LIDT (10 (J/cm2)
(10 ns @ 1064 nm) and can be applied for high power
lasers. There are Reflection and Transmission configurations:
Fig 1. Schematic explanations of optical design of transmission (LPA-A)
type laser power attenuator.
Transmission
S - polarised
P - polarised
Half waveplate
Brewster type
polariser
Input
Output
5

3. Product description"
Advanced laser power attenuator LPA-A is a compact
motorised device for laser power control with integrated
controller and absolute position encoder.
The LPA-A is produced in the UV, visible and NIR spectral
ranges, from 250 nm to 2000 nm. This device is combined
with the unique mechanical design which ensures
repeatability and high stability of performance.
All optical components of the LPA-A are made for high LIDT
and provide stable and reliable performance even using
them with high power lasers in industrial applications.
A secondary laser beam from laser power attenuator unit
can be rejected to an external beam dump. The beam dump
is used for avoiding any thermal effects or stress in the
housing of the LPA-A device.
3.1. Optical specifications"
3.2. Mechanical specifications"
3.3. Electronic specifications"
3.4. Conditions"
Clear input aperture
ø15 mm
Clear output aperture
ø15 mm
Power attenuation range
<0.1 % to >98 %
LIDT coating
>10 [J/cm2] (10 ns @ 1064 nm)
Adjustment time
< 0.2 sec (min to max)
Aboslute pos. encoder
Yes
Resolution
175,542 µsteps in full rotation
(0.002 deg, 7.2 arcsec, 0.035
mrad)
Accuracy
± 0.005 deg,
(±18 arcsec, 0.087 mrad, less
than ±0.01 %)
Motor
2 phase stepper motor,
200 steps with 256 µstepping
Available coatings
A. Standard wavelenghts, nm
1st harm
2nd harm
3rd harm
1064
532
355
1020 - 1040
510 - 520
343
760-840
390 - 410
-
C. Custom wavelenghts
Custom coating available
LPA-A
LPA-A with $
beam dump
Lenght
86 mm
86 mm
Width
47 mm
64 mm
Height
58 mm
58 mm
Interface options:
Terminal
Using commands described
in p. 12 “Commands”
Software
Using LPA-A software
Input voltage
DC 12 V
Transmission speed
up to 115,200 bits/s (RS-232)
full speed USB 2.0
Operating temperature
+10 0C to +40 0C
Storage temperature
-15 0C to +50 0C
6

3.5. Controller"
3.5.1. Interfaces, pinout"
1. There are two contacts:
691382000005 for communication;
691382000002 for Power supply - DC 12 V
Fig 3. Side view of LPA-A.
3.6. Voltage levels"
The RS-232 standard defines the voltage levels that
correspond to logical one and logical zero levels for the data
transmission and the control signal lines. Valid signals are
either in the range of +3 to +15 volts or the range −3 to −15
volts with respect to the "Common Ground" (GND) pin;
consequently, the range between −3 to +3 volts is not a
valid RS-232 level. For data transmission lines (TxD, RxD),
logic one is defined as a negative voltage, the signal
condition is called "mark". Logic zero is positive and the
signal condition is termed "space".
LPA-A operates on signal levels of ±5#V and can accept
signal levels of up to ±15 V. Because the voltage levels are
higher than logic levels typically used by integrated circuits,
special intervening driver circuits are required to translate
logic levels. These also protect the device's internal circuitry
from short circuits or transients that may appear on the
RS-232 interface and provide sufficient current to comply
with the slew rate requirements for data transmission.
3.7. What’s in the box?"
Standard kit includes:
1. Integrated motorised laser power attenuator
2. Software
3. Power supply DC 12V
4. USB (1.5 m) cable
NOTE: Other accessories must be purchased separately.
3.8. Available accessories"
Type
Contact
Connector
Communication
691382000005
691381000005
Power supply
691382000002
691381000002
1 2 3 4 5
1 2
DC 12V
RS232, USB
PINOUT
DC 12 V
RS232
USB
1. +12 V DC
3. GND
1. USB D-
2. GND
4. RS232 RX
2. USB D+
5. RS232 TX
3. GND
Beam dump (<6W): $
(with AR/AR coated window)$
for all standard wavelengths
• 1064, 1030
• 532, 515
• 343, 355
• 247, 266
RS232 cable:$
• 1.8 m
• 5 m
• 10 m
• 15 m
7

4. Software"
4.1. Minimum Hardware
requirements (recommended)"
4.2. System requirements"
To install the application you must have administrator rights
on your computer.
To run LPA application Microsoft .NET 4.5.2 Framework or
later must be installed. The installer detects Microsoft .NET
Framework and installs it. Administrator privileges are
required for installation. Contact your network administrator
if you do not have administrator rights on the computer.
4.3. Supported client operating
systems"
•Windows Vista SP2
•Windows 7 SP1
•Windows 8
•Windows 8.1 (.NET included with OS)
•Windows 10 (.NET 4.6 included with OS)
•Windows Server 2008 SP2/R2
•Windows Server 2012 (.NET included with OS)
4.4. Installing the software"
1. Check and download the latest LPA software from our
website (www.optogama.com, www.4lasers.com) or
contact us directly at [email protected].
2. Run the downloaded software installation file. Installation
window will appear, click “Next” to continue:
3. Select “Create a desktop shortcut” if it is necessary and
click “Next”:
Review setup information and proceed the installation. To
continue click “Install”:
4. Setup will finish the installation:
Processor
1 Ghz
RAM
512 Mb
Disk space
32-bit
4,5 Gb
64-bit
4,5 Gb
8

5. Press “Finish” to end the installation:
Connect the device and controller via HD-15 cable.
6. Connect the PC and controller via USB or RS232 cable.
7. Plug in power supply to controller and AC adaptor to wall
outlet.
8. The device will be detected and configured.
9. The device installation is complete.
9

4.5. Using the software"
CAUTION! Do not switch the laser ON if the device is not
adjusted properly, it may damage or destroy optical
elements.
Launch LPA program using LPA icon on the desktop.
4.5.1. Connection, device selector"
10. Device selector window will appear. Select COM port (to
which the laser power attenuator is connected) from the
drop down menu. Press “Connect” to connect the
device or “Rescan” if your device is not visible.
Select “Filter” when device is connected via USB cable.
All other COM ports will be hidden except our device.
NOTE: When connecting via RS232 cable “Filter” must
be deselected, otherwise device will not be visible.
4.5.2. Settings, calibration"
11. Using laser power attenuator for the first time the
calibration is required. The information window will
appear:
12. For LPA-A calibration, move your mouse to the left side
of the window on a gear symbol from the sliding menu
and select “Settings”. Settings menu will appear:
13. To succeed calibration please follow calibration steps:
1. Set default settings.
2. Find minimum laser power position.
3. Set current position as minimum power “Set zero”.
4. Choose additional measurement units if necessary
5. Select procedure after turning the device ON. By
default the device will reach last desired value
6. Calibration is done and device is ready to use.
Press “Finish” and you will be greeted into MAIN
window.
LPA
10

4.5.3. Main window!
11
Preset buttons"
Click “Edit” to add or edit
preset t values for a quick
change
Settings"
Select this icon to open
calibration window to calibrate
an attenuator and change it’s
settings
Desired power value in %"
Enter required power value.
Press “Enter”.
Power Slider"
Move the slider to change into
required power level
Buttons for incremental
change"
Click yellow button for
incremental change. Double-
click on the number to change
the increment size.
Save as preset"
Save current transmitted laser
power value as preset button
in required slot.
Emergency zero"
If active, the attenuator will
instantly go to minimum
position - 0%.
Desired power value in your
desired units"
Enter required power value.
Press “Enter”. To enable go to
“settings”
Connection$
Green - device is connected
Status$
Green blinking - in motion"
Green - target is reached
Error$
Red - indicates and error. Drag
cursor here to obtain error
Reconnect"
Select this icon to reconnect
the device if it is disconnected
Sliding Menu"
Drag cursor here to expand
menu
Command line"
Select this icon to open
command terminal window
Device selector tab
Connected device tab
About$
Click to open About window
for FW upgrader and manual
Connection type"
Shows device’s connection
type: RS232 or USB
Actual value"
Shows actual value which is
read from absolute encoder

4.6. Updating the firmware"
If your device firmware version doesn’t match to software’s
firmware version while connecting to device via LPA
software you’ll be asked to update your device. If update
request pops-up, but you want to keep current firmware
and use LPA software, you must use software compatible
with that firmware version.
NOTE: Compatible software had been delivered with
device.
In order to update your device or rewrite device firmware -
USB cable must be used (update through RS232 cable is
not available).
1. Click button “Firmware Upgrader” in the About tab of
LPA software:
2. In the opened window press “Update” button. You will
be asked if you really want to update device:
After a warning device motors will be shut down and
update will start:
3. Update should be done in about a minute. If everything
went successfully message box like this should pop-up:
Now you’re ready to go.
12

4. Commands"4.1. Interface!
The device can be controlled using either USB 2.0 or
RS-232 interface. The device will switch to the required
interface upon connection of the appropriate cable.
When using the RS-232 interface, the controller
communicates on the configured baud rate (see
Command descriptions), using 8 data bits, no parity and
1 stop bit.
When the device is connected to the PC through the USB
interface, it will appear as a Virtual Serial COM port, so
all PC side communications are interchangeable between
the two interfaces.
All communications with the device are conducted by
sending literal ASCII string commands terminated with
the newline character \n. For example, the power can
be set to 10% by issuing a “LPA>PWR!_10\n” command
to which the device will respond with “LPA>PWR_10\n”.
4.2. Description"
Command
Response
Comments
Example usage
User command
Device response
Motion | Power - PWR, Angle - ANG, Stop - STP
LPA>PWR?
LPA>PWR_X.XXX
Command used to get the current power
value in percentages. (Read and
calculated from absolute encoder)
LPA>PWR?
LPA>PWR!_45.125
LPA>PWR!_X.XXX
LPA>PWR!_X.XXX
Command used to set a new power value
in percentages.
LPA>PWR!_10
LPA>PWR_10.000
LPA>PWR!_45.1
LPA>PWR_45.100
LPA>PWR!_0.07
LPA>PWR_0.070
LPA>ANG?
LPA>ANG_X.XXX
Command used to get the current angle
value in degrees. (Read from absolute
encoder, 0-360 deg)
LPA>ANG?
LPA>ANG_22.143
LPA>ANG!_X.XXX
LPA>ANG_X.XXX
Command used to set the angle value in
degrees (0-360)
LPA>ANG!_22.5
LPA>ANG_22.500
LPA>STP!
LPA>STP
Command used to stop motor instantly.
Device could be used normally, homing is
not require.
LPA>STP!
LPA>STP
Calibration| Calibration - DEF
LPA>DEF!
LPA>DEF_offset
Command used to define current
waveplate position as minimum power
position. Used for calibration.
LPA>DEF!
LPA>DEF_34.067
LPA>DEF?
LPA>DEF_offset
Command used to get an offset value
from zero to minimum power. Used for
calibration.
LPA>DEF?
LPA>DEF_34.067
Settings | Baud rate - BAUD, Buttons lock - KEYLOCK, Default settings - LDF
LPA>BAUD?
LPA>BAUD_baud rate
Command used to get baud rate.
LPA>BAUD?
LPA>BAUD_115200
LPA>BAUD!_baud rate
LPA>BAUD_baud rate
Command used to set baud rate. 115200
by default. Available speeds:
115200, 57600, 38400,
19200, 9600, 4800.
Other values are ignored.
LPA>BAUD!_57600
LPA>BAUD_57600
LPA>LDF!
LPA>LDF
Command used to load default settings. Device after this command must be recalibrated.
13

Information | Device state - STATUS, Wavelength - WL, Firmware v. - FW, Serial number - ID
LPA>STATUS?
LPA>X_Y
Command used to get the current state of
the device. X signifies if motor is ON. Y
signifies the error byte.
X=”1” motor is ON (enabled)
X=”0” motor is OFF (disabled)
Y = 16 bits digit with following bits:
bit0 -> driver error
bit1 -> driver high temperature warning
bit2 -> driver over temperature
bit3 -> some type of error in the driver
load
bit4 -> load warning – open load on
phase A or B
bit5 -> under voltage error
bit6 -> external memory error, working/
calibration data may be corrupted
bit7 -> reset has occurred
bit8 -> -
bit9 -> -
bit10 -> target position is reached
bit11 -> -
bit12 -> motor is stand still
bit13 -> -
bit14 -> -
bit15 -> device calibration is done
LPA>STATUS?
LPA>1_0
LPA>STATUS?
LPA>0_0
LPA>STATUS?
LPA>1_2
LPA>WL?
LPA>WL_XXX
Command used to get the design
wavelength.
LPA>WL?
LPA>WL_355
LPA>FW?
LPA>_Firmware version
Command used to get firmware version.
LPA>FW?
LPA>_1.0.0.1
LPA>ID?
LPA>_LPAAXXXXXX
Command used to get serial number.
LPA>ID?
LPA>_LPAA190001
Other | Echo, Reset, Motor ON/OFF
LPA>ECHO!
LPA>ECHO
Command used for troubleshooting. The
device echoes sent command before
sending the response.
LPA>ECHO!
LPA>TGT?
LPA>ECHO
LPA>TGT?
LPA>TGT_45602
LPA>NOECHO!
LPA>NOECHO
Command used to disable ECHO command.
LPA>RESET!
LPA>RESET
Command used to reinitialise device.
LPA>RESET!
LPA>RESET
LPA>OFF!
LPA>OFF
Command used to turn motor OFF.
LPA>OFF!
LPA>OFF
LPA>ON!
LPA>ON
Command used to turn motor ON.
LPA>ON!
LPA>ON
Command
Response
Comments
Example usage
User command
Device response
14

4.3. Serial communication example in Python"
!
15

5. Technical drawings"
16

"
17

OPTOGAMA, UAB
Mokslininku str. 2A,
LT-08412, Vilnius, Lithuania
[phone]
[email protected]
www.optogama.com