Altechna PowerXP User manual

Watt Pilot
Motorized
Attenuator
Quick Start Guide
PowerXP
Compact Motorized
Attenuator
User Manual
2019 version L.4.00

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Contents
1. Introduction 3
1.1. PowerXP short description 3
1.2. General safety requirements 4
1.3. Regulation 4
1.4. Operating and storage conditions 5
2. Operation Principle 5
3. Package Contents 6
3.1. Optics (dis)assembling 6
4. PowerXP Soware Description 7
4.1 “AltOne” soware 7
4.2. Computer requirements 7
4.2. Soware installation 7
4.3 Program first run 10
4.4. “Select Device” tab page 10
4.5. “Calibration” tab 11
4.6. “PowerXP” tab 13
4.7. “Settings” tab 14
4.8. “User Manual” tab 15
4.9 “About” tab 15
5. PowerXP Controller Hardware 16
5.1. Controller specifications 16
5.2. Controller usage 16
6. Serial and Ethernet Communication 17
6.1 Serial protocol description 17
6.2 Ethernet protocol description 18
6.3 Command execution 18
6.4 Controller Commands 21
7. Main Dimensions 23
7.1. PowerXP 23
7.2. PowerXP Controller 23

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PowerXP
April 2019
Copyright © 2019 Altechna, UAB. All rights reserved.
No part of this manual, including the products and soware described in it, may be
reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any
language in any form or by any means, except documentation kept by the purchaser for backup
purpose, without the express written permission of UAB Altechna (hereinaer Altechna).
Product warranty or service will not be extended if:
1. The product is repaired, modified or altered. Unless such repair, modification of alteration
is authorized in writing by Altechna.
2. The LOT number of the product is defaced or missing.
Altechna provides this manual “as is” without warranty of any kind, either express or
implied, including but not limited to the implied warranties or conditions of merchantability
for a particular purpose. In no event shall Altechna, its directors, employees or agents be
liable for any indirect, special incidental, or consequential damages (including damages
for loss of profits, loss of business, loss of use or data, interuption of business and the like),
even if Altechna has been advised of the possibility of such damages arising from any defect
or error in this manual or product.
Specifications and information contained in this manual are furnished for informational use
only, and are subject to change at any time without notice, and should not be construed as
a commitment by Altechna. Altechna assumes no responsibility or liability for any errors or
inaccuracies that may appear in this manual, including the products and soware describedin it.
This manual is directly connected to firmware version. Latest firmware, soware and
manual versions can be downloaded from www.altechna.com.
Products and corporate names appearing in this manual may or may not be registered
trademarks or copyrights of their respective companies, and are used only for identification or
explanation and to the owner’s benefit, without intent to infringe.
1. Introduction
This user manual is designed to help to install and operate PowerXP. Before installing and
operating PowerXP please read installation and operation instructions carefully. Safety
instructions must be read carefully. If there are any questions about contents of this manual,
please contact [email protected]om. Altechna reserves the right to update contents of this
manual without any notification.
1.1. PowerXP short description
Compact motorized attenuator - PowerXP is a computer-controlled laser beam attenuation
device. It attenuates a free space laser beam/pulse continuously without introducing additional
energy fluctuations. PowerXP is controlled by a computer via via USB or RS232 connection.

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1.2. General safety requirements
Compact motorized attenuator is designed to operate in conjunction with laser systems.
All applicable rules and regulations for safe operation of lasers must be known and applied
while installing and operating PowerXP. The customer is solely responsible for laser safety
while using PowerXP as a standalone device or integrated into system. The customer must
consider protective measures.
While assembling or operating PowerXP, do not stare at the direct or scattered laser
light even with safety goggles. All parts of the body must be kept away from the laser
radiation. While adjusting laser beam through PowerXP, laser power must be kept as
low as possible. Hazardous laser radiation can increase while optical components or
instruments are used in combination with PowerXP. Appropriate eye protection must
always be worn at all times. Electrical safety requirements must be complied while
assembling and operating PowerXP.
1.3. Regulation
Attention!
The following statement applies to the products covered in this manual, unless otherwise
specified herein. The statement for other products will appear in the accompanying
documentation.
These limits are designed to provide reasonable protection against harmful interference in
a residential installation. This equipment generates, uses, and can create radio frequency
energy and, if not installed and used in accordance with the instructions, may cause
harmful interference with radio communications. However, there is no guarantee that
interference will not occur in a particular installation. If this equipment causes harmful
interference to radio or television reception, which can be determined by turning the
equipment o and on, the user is encouraged to try to correct the interference by one or
more of the following measures:
•Reorient or relocate the receiving antenna
•Increase the separation between the equipment and receiver
•Connect the equipment into an outlet on a circuit dierent from that to which the
receiver is connected
•Consult the dealer or an experienced radio/TV technician for help
Altechna is not responsible for any radio or television interference caused by modifications of
this equipment or the substitution or attachment of connecting cables and equipment other
than those specified by Altechna. The correction of interference caused by unauthorized
modification, substitution or attachment will be treated as responsibility of the user.

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Attention!
Cellular phones or other radio transmitters are not recommended to be used within the range
of three meters of this unit since the electromagnetic field intensity may then exceed the
maximum allowed disturbance values according to IEC 61326-1.
1.4. Operating and storage conditions
For proper PowerXP functioning please use the assigned controller (found in the same
package). Using unassigned controllers might be harmful to the device.
Environmental conditions that must be hold while storing, servicing and operating are:
•Storage temperature should be between -25 °C and +60 °C
•Operating temperature is 25 °C ± 10 °C
•PowerXP must be protected from humidity, dust and corrosive vapors to avoid damaging
optical components and electronics
•Avoid strong static electricity and electromagnetic fields
2. Operation Principle
PowerXP incorporates a rotating quartz λ/2 phase waveplate and one polarizer which separate
s-polarized and p-polarized beams (fig. 1). The intensity ratio of the two beams may be
continuously varied without alteration of other beam parameters by rotating the waveplate.
Proper functioning of PowerXP requires optimal configuration of optical elements regarding
to incident laser beam polarization contrast. Higher incident laser beam polarization contrast
leads to higher PowerXP output polarization contrast.
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2. Operation Principle
p-pol
Brewster type
thin film polarizer
Incident linearly
polarized laser beam
Rotating λ/2
waveplate
Beam dump
s-pol
Figure 1. PowerXP operation principle. The intensity of the incident beam is varied by means of
a λ/2 phase waveplate and a polarizer.
PowerXP incorporates a rotating quartz λ/2 phase waveplate and one
polarizer which separates s-polarized and p-polarized beams (g. 1).
The intensity ratio of the two beams may be continuously varied without
alteration of other beam parameters by rotating the waveplate. Proper
functioning of PowerXP requires optimal conguration of optical elements
considering the polarization contrast of the incident laser beam. Higher
incident laser beam polarization contrast leads to higher PowerXP output
polarization contrast.
PowerXP_User_manual_A5_06_20161107.indd 10 07/11/2017 18:08
Figure 1. PowerXP operation principle. The intensity of the incident beam is varied by means of
a λ/2 phase waveplate and a polarizer.

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3. Package contents
•Compact motorized attenuator - PowerXP
•Controller
•USB cable (2 m length recomended but no longer than 3 m)
•12 V power supply
•Soware, installation instructions in USB flash
•Polarizer – (already in the attenuator)
•Waveplate – (already in the attenuator)
3.1. Optics (dis)assembling
In order to get maximum possible attenuation polarizer adjustment is necessary. The back
cover with beam dump can be removed by untightening two screws showed in fig. 2. Aer
removing the closure, 3 microscrews will be uncovered (circled in red). Adjusting them while
measuring laser power output, will allow to reach maximum attenuation.
If necessary, the waveplate and polarizer holder can be removed for cleaning purposes.
To remove the waveplate just untighten the retaining ring and take out the waveplate. For
removing the polarizer holder please remove 3 steel screws and carefully pull it from the main
PowerXP body.
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Figure 2. Disassembly of PowerXP. Adjustment microscrews circled in red. To remove the cover
loosen two screws on each side of PowerXP (marked with yellow circle)
λ/2 waveplate
PowerXP_User_manual_A5_06_20161107.indd 12 07/11/2017 18:08
Figure 2. Disassembly of PowerXP. Adjustment microscrews circled in red. To remove the cover
loosen two screws on each side of PowerXP (marked with yellow circle).

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4. PowerXP Soware Description
4.1 “AltOne” soware
“AltOne” soware is dedicated soware for all Altechna products. It is designed to
automatically detect dierent Altechna products by the product serial number.
Soware can operate only when connected to “USB” or “RS232” ports. When communicating
through “Ethernet” port you should established connection by oneself considering your
system’s configuration.
4.2. Computer requirements
•Free USB port or RS232 port. PowerXP is compatible with USB 1.1, USB 2.0 and USB 3.0
Computer administrator rights (only for installation)
•Windows XP sp3 (32-bit)
•Windows Server 2003 sp2 (32-bit)
•Windows Vista sp1 (32/64-bit)
•Windows Server 2008 (32/64-bit)
•Windows 7 (32/64-bit)
•Windows 8 (32/64-bit)
•Windows 10 (32/64-bit)
•Microso.Net framework 4.0 redistributable (installs automatically)
•Adobe Acrobat Reader 7.0 or above
4.2. Soware installation
“AltOne” is dedicated soware for all Altechna products. All products from Altechna should
work with this soware and it is not required for multiple installations.
1. Run the “AltOne-Setup.exe” installation file. In case the soware is installed on an
operating system that does not meet requirements, only USB drivers will be installed. Click
“Yes” to continue.
2. Installation window will appear, click “Next” to continue:

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3. Click “Next”:
4. Select installation directory and click “Next” to begin installation:

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5. “AltOne” soware requires “Microso.NET Framework 4 Client Profile” or higher version
to be installed. Setup will oer to download it, choose “Yes” if active internet connection
is available. Choose “No” to download it from www.microso.com/en-us/download/
details.aspx?id=17113 and install it manually. One should choose “No” if newer version
of Microso.NET framework is unwanted, or working internet connection is not available.
This dialog will not appear if framework is already installed. Download size is 42 Mbytes.
6. Setup will download “Microso .NET Framework 4 Client Profile”.
7. Aer download is finished, “Microso .NET Framework 4 Client Profile” will be installed,
wait for it to complete. This can take more than 10 minutes on slower machine.
8. Setup will finish by installing drivers. Click “Next” to continue:
9. Click “Finish” to end installation. The program cannot be opened if only drivers were
installed (see step 2 for details).

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10. “AltOne” soware icon will appear on “All Users” desktop and “All Users” start menu.
When using PowerXP with USB:
1. Connect PowerXP to its controller.
2. Connect PowerXP controller and PC via USB cable.
3. Plug in PowerXP power supply jack.
4. Windows will detect new hardware. Wait until windows configures new device.
4.3 Program first run
Launch “AltOne” program using “AltOne” icon on desktop or from “Start Menu → All Programs
→ Altechna → AltOne → AltOne”. AltOne “Select Device” window will appear. At least one device
must be displayed on the list. If the list is empty, please check USB/RS232 cable, power
connection. Red LED must be active if power is OK. Click refresh button to rescan all ports.
4.4. “Select Device” tab page
“Select Device” tab contains a list of currently connected and powered attenuators. This
window is used to choose device to work with if there are several controllers connected to a
single computer. Functions of this window are described in the picture below.
Figure 4. AltOne “Select Device” tab. It is displayed every time program is started. There is one
device (PowerXP) attached to PC in shown screenshot. Click “Connect” to load control tabs for it.

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Every device in “Select Device” tab list has information about connected device. This
information contains:
•Device picture
•Device type
•Device serial
•Port name
•Connection type (“USB” or “RS232”)
Every device in the list can be connected using “Connect” button.
In case of multiple device connection at the same time use pop-up icon “ ” in the top right
corner to open device in separate window.
4.5. “Calibration” tab
Aer successful connection to your device you should be automatically redirected to main
control tab (Figure 5.).
Figure 5. PowerXP tab.
If your device is not calibrated all controls will be disabled. To calibrate your device, go to
“Calibration” tab.

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Figure 6. Calibration tab.
Calibration procedure:
In order to correctly change the output power, the soware needs to know the angle of the
λ/2 waveplate’s fast axis. It can be fixed in any angle with respect to the rotator. The purpose of
calibration is to fix angular oset between the λ/2 waveplate and the rotator hardware zero position.
1. On “1st Step” click on “Zero Point Calibration”. This will drive the waveplate holder to
hardware limit switch (zero position). Step 1 must be performed every time the device is
turned on or aer extensive period of usage to eliminate any accumulated position error.
2. At “2nd Step” select correct clear aperture (CA) of currently connected attenuator.
Waveplate CA could be 8 or 15 mm in diameter.
3. Rotate waveplate by using buttons in section “3rd Step”, and measure laser power aer
the attenuator. Numbers on the text box represent motor moving distance (expressed in
stepper motor steps) and “+”/
“-” buttons represent rotation direction. One step equals to 0.003125 degrees.
Note
It is advised to search for lowest power (max attenuation) position, because usually it can be
spotted more easily and accurately.
4. Find minimum or maximum signal power and select the appropriate check box (“Min
Power” or “Max Power”). Angular oset is recalculated and shown in “Oset” field every
time check box selection is clicked. At this moment, main calibration goal is completed
and “Apply Oset” button should be clicked (if necessary oset value can be entered
manually to an oset value box).
Further step is not mandatory, but should be considered for convenience.
5. Calibration result can be verified by using buttons in “4th Step” panel. By clicking “Min
Power” or “Max Power” motor will go to minimum or maximum power position. If
everything is properly calibrated, you should see minimum or maximum attenuation.

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4.6. “PowerXP” tab
“PowerXP” tab is used to change laser power aer PowerXP attenuator. Main components of
this window are described below (Figure 7).
Figure 7. PowerXP tab.
Power meter panel always shows existing power aer the attenuator. Percentage range is
from 0% to 100% of transmission. Zero percent means that waveplate occurs at 45 degrees
angle, beam polarization is rotated by 90 degrees and is maximally attenuated. Display reading
“100%” means that waveplate is rotated at minimum attenuation – maximum transmission
angle.
Slider changes power from 0% to 100% (or from minimum to maximum custom units of
measure) with resolution of 0.1%. There is a “Min” and “Max” labels which when clicked drive
attenuator to minimum or maximum power accordingly.
Enter required value field is used to manually enter value of PowerXP power. Decimal point
symbol is “.” (dot), two decimal places can be used. Valid range is 0.00% ... 100.00% (when using
dierent units of measure these values will be dierent). Aer entering desired value just hit
“GO” button and value will be set.
Buttons “+” and “-” are used to adjust power continuously according to a button sign.
Preset buttons can be used to quickly set discreet values of output power. Button values could
be changed in “Settings” tab. In order to use preset buttons, go to “Settings” tab to enable
this function. This function is turned o by default.
Button “Zero point calibration” is used to recalibrate physical zero point of the device from
which all movement of waveplate is calculated.

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4.7. “Settings” tab
Figure 8. “Settings” tab.
In the “Settings” tab you can:
•Change controller name (up to 15 characters)
•Change rotation speed of the waveplate
•Change acceleration of the waveplate
•Change deceleration of the waveplate
•Change rotation speed when using physical buttons (“first speed”*)
•Change rotation speed when using physical buttons (“second speed”*)
•Change units of measure and minimum and maximum values which will represent
minimum and maximum attenuation
•Enable preset buttons
•Change preset buttons values
•Load default settings by clicking on “Load Default Settings”
* When using physical buttons to rotate waveplate firstly waveplate moves with “first speed”
and then aer 2 seconds starts to move with “second speed”.

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4.8. “User Manual” tab
In this tab you can comfortably read user manual of your PowerXP.
Figure 9. “User manual” tab.
When you enter this tab, you can maximize this window for greater readability. Also, you can
zoom, print, change page and save document as if you where using “Adobe Acrobat Reader”
soware.
This tab only works if you have “Adobe Acrobat Reader” soware for reading PDF files.
4.9 “About” tab
In this tab you can see your product name, soware version and controller’s firmware version.
Figure 10. “About” tab.

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5. PowerXP Controller Hardware
5.1. Controller specifications
PowerXP controller is bipolar stepper motor driver with specifications listed in Table 1 below.
Table 1. Controller specifications
Characteristic Rating
Max output voltage +12 V
Max output current 2 A
Current regulation type Pulse Width Modulation
Microstepping capability Steps 1/256
Position feedback Open loop operation
(no external position feedback encoder)
Controller protection Driver have overheating and over current (2 A) protection
Device can be operated by USB, RS232 and Ethernet
Limit switch One limit switch can be connected and used only for homing
Connector 26 pin D-SUB connector
5.2. Controller usage
FRONT VIEW
The following connections are situated in the front of PowerXP controller: power jack (12 V), 26
pin D-SUB for motor, Ethernet and RS232 connectors for PowerXP (Figure 12).
A A
B B
C C
D D
E E
F F
8
8
7
7
6
6
5
5
4
4
3
3
2
2
1
1
UAB ALTECHNA Mokslininkų st. 6A
08412 Vilnius, Lithuania
Designed by:
R.Andrulionis
Scale
1:1 A3
Size
One Controller
Part No
.
OneC-1.0
Weight
N/A
Sheet
1/1
Figure 11. Front view of PowerXP Controller.

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TOP VIEW
There are two buttons in the top of the PowerXP controller: MIN and MAX.
•MIN (-) – while holding turns the waveplate to a minimum attenuation
•MAX (+) –while holding turns the waveplate to a maximum attenuation
•HOME - holding both MIN/MAX buttons for 3 sec. moves attenuator to home position
There are 4 LED indicators:
•Power – indicates power from USB connection with PC
•Status:
•If blinking slowly (1 blink in 1 sec.) – need to set homing position
•If blinking fast (3 blinks in 1 sec.) – the waveplate is rotating
•If iluminating continuously – PowerXP is homed, the movement is stopped
•MIN – the PowerXP is at its minimum attenuation
•MAX – the PowerXP is at its maximum attenuation
Figure 12. Top view of PowerXP Controller.
6. Serial and Ethernet Communication
6.1 Serial protocol description
When using “RS232” (or “USB”*) port all communication between controller and PC (or other
device) is established by using RS232 communication protocol.

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COM-port parameters are fixed on the controller-side:
Speed: 115200 baud
Frame size: 8 bits
Stop-bits: 1 bits
Parity: none
Flow control: none
Byte receive timeout: 400 ms
*USB port simulates COM port on a PC.
All the commands are the same for all communication protocols (see “6.4 Controller
Commands”).
For more information please see “RS232 communication example” soware and C# code
(Visual Studio project).
6.2 Ethernet protocol description
When using “Ethernet” port all communication between controller and PC (or other device) is
established by using TCP/IP communication protocol. When controller is connected to “Ethernet”
port it constantly tries to connect to device (server) which IP address is specified in controller’s
memory. To connect and communicate with controller you should create dedicated TCP server
which will send and receive data to and from controller.
To achieve connection between server and the controller you must configure specific
addresses and ports in the controller and the server (they must match in both devices). You can
change controllers IP address and port using “TCP sample” soware.
When creating server on your device don’t use dynamic IP (DHCP), because your server IP
address should be static for controller to maintain the connection.
All the commands are the same for all communication protocols (see “6.4 Controller Commands”).
For more information please see “TCP sample” soware and C# code (Visual Studio project).
6.3 Command execution
All data transfers are initiated by the PC, meaning that the controller waits for incoming
commands and replies accordingly. Each command is followed by the controller response, with
rare exceptions of some service commands. One should not send another command without
waiting for the previous command answer.
Command processing does not aect real-time engine control (PWM and etc).

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Both controller and PC have an IO buer. Received commands and command data are
processed once and then removed from buer. Each command consists of 6-byte identifier
and optionally a data section followed by its 2-byte CRC. Data can be transmitted in both
directions, from PC to the controller and vice versa. Command is scheduled for execution if
it is a legitimate command and (in case of data) if its CRC matches. Aer processing a correct
command controller replies with 1 byte – AA (for “OK”) or 01 (for “not OK”), followed by data
and its 2-byte CRC, if the command is supposed to return data.
Device is a slave – it can’t initiate any data transfer. PC is a master. Each data transfer session
looks like:
Description Note
PC Send command
Device Confirm correct command receive
(0xAA or 0x01)
If 0x01 (not correct command), PC should
send command again
Device Send additional data to PC If needed to complete command
NOTE: OK - 0xAA, NOT OK - 0x01
In case of error in data from device to PC, PC initiate new session, starting from sending a command).
Each frame consists of start symbol (@), data string length (2 bytes), ASCII command
(always 3 bytes), data (if need to transmit some data for command execution), CRC (2 bytes)
which is calculated for ASCII command and DATA fields:
Start Length0, Length1 ASCII command DATA CRC0, CRC1
@ 0x00 0x00 A B C ...... ...... 0x00 0x00
Note for RS232 interface: device recognize end of the data frame if the pause aer last
transferred byte >50 ms.
Example command for homing:
Start
(“@”)
Length0, Length1
(3 bytes)
ASCII command
(“hom”)
DATA
(none) CRC0, CRC1
0x40 0x03 0x00 0x68 0x6f 0x6d ...... ...... 0xd5 0x94
For each correctly received command device answers - 0xAA. If command is not correct it will
answer - 0x01.

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Device calculate CRC, using this procedure ( C ):
uint16_t myCRC16_CCITT_CRC(uint16_t *crc, uint8_t c)
{
uint8_t i;
uint16_t cc;
cc = ( (uint16_t ) c ) << 8;
for ( i=0; i<8; i++ )
{
If (( (*crc) ^ cc ) & 0x8000)
(*crc) = ((*crc) << 1) ^ MTT;
else (*crc) <<= 1;
cc <<= 1;
}
return *crc;
}
Procedure for PC ( C# ):
//CRC16 XMODEM implementation
private static short calcCrc(byte[] data)
{
unchecked
{
short crc = 0;
for (int a = 0; a < data.Length; a++)
{
crc ^= (short)(data[a] << 8);
for (int i = 0; i < 8; i++)
{
if ((crc & 0x8000) != 0)
crc = (short)((crc << 1) ^ 0x1021);
else
crc = (short)(crc << 1);
}
}
return crc;
}
}