Altechna PowerXP User manual

PowerXP
Maxi Motorized
Attenuators
User Manual
2022 version v.1.09

2
Contents
PowerXP 3
1. Introduction 3
1.1. PowerXP Maxi short description 3
1.2. PowerXP Maxi main specifications 4
1.3. General safety requirements 4
1.4. Regulation 4
1.5. Operating and storage conditions 5
2. Operation Principle 5
3. Package Contents 6
4. PowerXP Soware Description 7
4.1. “AltOne” soware 7
4.2. Computer requirements 7
4.3. Soware installation 7
4.4. Program first run 10
4.5. “Select Device” tab page 10
4.6. “Calibration” tab 11
4.7. “PowerXp” tab 13
4.8. “Settings” tab 14
4.9. “User Manual” tab 15
4.10. “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 17
6.3. Command execution 17
6.4. Controller commands 20

3
PowerXP
November 2022
Copyright © 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. 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 Maxi short description
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 USB.
There are 4 dierent configurations of PowerXP Maxi:
• PowerXP Maxi Transmission type – attenuator with one polarizer, for using transmitted beam.
• PowerXP Maxi Reflection type – attenuator with two polarizers, for using transmitted or/and reflected beams.

4
• PowerXP Maxi Cube type – attenuator with polarizing cube, for using transmitted or/and reflected beams.
• PowerXP Maxi Collinear type – attenuator with polarizer and compensator, for using transmitted beam, whereas
preserving collinear input and output beams for preservation of inntial beam path.
1.2. PowerXP Maxi main specifications
Typical application High power CW and pulsed lasers
Time between min and max <0.2 s
Resolution 0.001875 deg
Damage threshold >20 J/cm2@ 1064 nm, 10 ns, 10 Hz
Attenuation range <0.1 – >99%
1.3. 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. Electrical safety requirements must be
complied while assembling and operating PowerXP.
1.4. 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

5
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.
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.
1.5. 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 for storage, service and operation are:
• storage temperature should be between -30 °C and +30 °C
• operating temperature is 25 °C ± 15 °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 Maxi incorporates a rotating quartz λ/2 phase waveplate and one or two polarizers or polarizing cube 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.
Half-wave plate
56°
Linearly
polarized
beam
Brewster TFP
p-pol
s-pol
Brewster TFP
Figure 1a. PowerXP Maxi R-type operation principle.

6
°
p-pol
s-pol
Half-wave plate
56
Linearly
polarized
beam
Brewster TFP
Beam dump
Figure 1b. PowerXP Maxi T-type operation principle.
p-pol
Walk-o compensator
Beam dump
Brewster TFP
Half-wave plate
Linearly
polarized
beam
56 °
s-pol
Figure 1c. PowerXP Maxi CL-type operation principle.
Linearly
polarized
beam
Half-wave plate
s-pol
p-pol
Figure 1d. PowerXP Maxi C-type operation principle.
3. Package Contents
• Compact motorized attenuator - PowerXP
• Controller
• USB cable
• 12 V power supply
• Soware, installation instructions in USB flash
• Polarizer – (already in the attenuator)
• Waveplate – (already in the attenuator)

7
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.
4.3. 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:

8
3. Click “Next”:
4. Select installation directory and click “Next” to begin installation:
5. “AltOne” software requires “Microsoft.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.

9
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).
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.

10
4.4. 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.
4.5. “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 4a. 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.
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.
RS232 connection
In case of connecting device via RS232, you should add devices manually. To do that check “RS232” check box near
the “Refresh” button, then dropdown box and button “add” will appear. When you click on dropdown box, soware will
populate it with all ports available to PC. Then you just select specific port and push button “add” to add new RS232 device
to a “Select Device” window.

11
Figure 4b. AltOne “Select Device“ tab. RS232 connection controls are on the top right corner.
4.6. “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.

12
Figure 6. Calibration tab.
Calibration procedure:
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 0.001875 degrees.
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.
Note:
It is advised to search for lowest power (max attenuation) position, because usually it can be spotted more
easily and accurately.
You only need to find minimum or maximum power only once. When you push “Apply Oset” oset value is
saved to internal memory of the controller and is retrieved even if device has been powered o.
4. 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.

13
4.7. “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. 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.

14
4.8. “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“.

15
4.9. “User Manual” tab
In this tab you can confortabily 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.
4.10. “About” tab
In this tab you can see your product name, soware version and controller’s firmware version.
Figure 10. “About” tab.

16
5. PowerXP Controller Hardware
5.1. Controller specifications
PowerXP controller is bipolar stepper motor driver with specifications listed in Table 1 below.
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 (2A) 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
Table 1. Controller specifications.
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
(fig.12).
Figure 11. Front view of PowerXP Controller.
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 3sec
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 homing
• If blinking fast (3 blinks in 1 sec.) – the waveplate
is rotating
• If iluminating continiously – 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.

17
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.
COM-port parameters are fixed on the controller-side:
Speed: 115200 baud
Frame size: 8 bits
Stop-bits: 1 bit
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 do not 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).
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.

18
Device is a slave – it cannot 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 (16 bits), ASCII command (always 3 bytes), data (if
need to transmit some data for command execution), CRC (16 bits) 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.
For each correctly received command device answers - 0xAA. If command is not correct it will answer - 0x01.
Example command for homing:
Start (“@“) Length0, Length1 (3 bytes) ASCII command (“hom“) DATA (none) CRC0, CRC1
0x40 0x03 0x00 0x68 0x6f 0x6d …… ……. 0xd5 0x94
Example command for moving to “123456” absolute position:
Start
(“@“) Length0, Length1 (3 bytes) ASCII command (“rad“) DATA (“123456”) CRC0, CRC1
0x40 0x07 0x00 0x72 0x61 0x64 0x40 0xE2 0x01 0x00 0x1C 0xFD

19
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;
}
}

20
6.4. Controller commands
Movement commands
Command Data Return
values
Description Notes
“hom”
(0x686F6D)
none 0xAA or 0x01
(OK or NOTOK)
Start the homing
procedure.
“rad”
(0x726164)
4 bytes 0xAA or 0x01 Move to absolute micro
step position x.
Woks only when device is
“Homed”
“rgd”
(0x726764)
4 bytes 0xAA or 0x01 Move x micro steps relative
to the current position.
Woks only when device is
“Homed”
“rgs”
(0x726773)
4 bytes 0xAA or 0x01 Move x micro steps relative
to the current position.
Works even if device is not
“Homed”
“stp”
(0x737470)
none 0xAA or 0x01 Stop motor smoothly if it
is currently running.
Status and information commands
Command Data Return
values*
Description Notes
“ost”
(0x6F7374)
none 8 bytes
(debug)
+ 4 bytes
(flags)
+ 4 bytes
(position)
+ 8 bytes
(debug)
Get controller run state,
position, limit switch
states and etc.
“debug” bytes are just for
debugging purposes.
“flags” (logic 1 – active):
bit0 – device is running
bit1 – homing in progress
bit2 – device is not homed
bit3 – hardware error, can’t move
bit4 – calibration corrupted
bit5, bit6, bit7 – unused
bit8 – motor driver reset detected
bit9 – driver hi temp warning
bit10 – le LS is pressed
bit11 – error in load (motor)
bit12 – motor driver error
bit13 – stallguard is active
bit14 – motor is standstill
bit15 – target velocity reached
bit16 – driver over temperature
bit17 – target position reached
bit18 – under voltage error
bit19 – right LS is pressed
bit20 – device is homed
bit21 – calibration is done
bit22 – load warning (open load
detected on motor phase A or B)
bit23 – device FRAM error
“pw “
(0x707720)
none 16 bytes
(char)
Show serial number of a
device.
“n “
(0x6E2020)
none 17 bytes
(char)
Show name of a device.
“v “
(0x762020)
none 5 bytes (char) Show firmware version of
a device.
“p “
(0x702020)
none 5 bytes (char) Returns “pUSB:” if device
is connected.
This command can be used to “ping”
controller (to check if controller is
attached to particular COM port).