1. Manuals
  2. Brands
  3. Lightware Manuals
  4. Measuring Instruments
  5. SF11
  6. Product manual

Lightware SF11 Product Manual

Laser altimeter
Hide thumbs Also See for SF11:
Table of Contents

Advertisement

Quick Links

Download this manual
SF11
Laser altimeter
The SF11 is a compact, lightweight
laser altimeter for above-ground-
level measurement from small fixed
wing or multi-rotor craft.
The SF11 laser altimeter is ideal for
automated landings, precision
hovering and terrain following.
The SF11 is directly compatible with
the Pixhawk and other flight
controllers.
The SF11 laser altimeter makes
accurate distance measurements to
solid surfaces up to an altitude of 120
meters and water up to 40 meters.
SF11 Laser Altimeter - Product Manual - Revision 6
Product manual
Features:
•
Very compact and lightweight - 35 grams.
•
Accurate AGL altitude measurements on ground,
foliage and water.
•
Fast update rate of 20 readings per second.
•
Includes serial, I2C, USB and analog interfaces
with programmable capabilities.
•
Easy to configure using the built-in menu and
LightWare Terminal software.
•
Fully calibrated and ready to run.
•
Compatible with Pixhawk, APM and other flight
controllers.
•
Accurate, reliable altitude measurements in
sunlight or dark conditions.
•
Not affected by: speed; wind; changes in
barometric pressure; noise; ambient light; terrain
or air temperature.
1
of
20
© LightWare Optoelectronics (Pty) Ltd, 2016

Advertisement

Table of Contents
loading

Related Manuals for Lightware SF11

Summary of Contents for Lightware SF11

  • Page 1 40 meters. • Not affected by: speed; wind; changes in barometric pressure; noise; ambient light; terrain or air temperature. SF11 Laser Altimeter - Product Manual - Revision 6 © LightWare Optoelectronics (Pty) Ltd, 2016...

  • Page 2: Table Of Contents

    Information found in this document is used entirely at the reader’s own risk and whilst every effort has been made to ensure its validity neither LightWare Optoelectronics (Pty) Ltd nor its representatives make any warranties with respect the accuracy of the information contained herein.

  • Page 3: Overview

    I2C ports. The SF11 works by measuring the time it takes for a very short flash of laser light to travel to the ground and back again. The accuracy of the measurement is not affected by the colour or texture of the ground nor the angle of incidence of the laser beam.

  • Page 4: Quick Start Guide

    Product manual 2. Quick start guide 1. CAUTION - The SF11 laser altimeter contains a laser and should never be aimed at a person or an animal. Do not look at the beam directly with optical instruments. 2. Download LightWare Terminal software from www.lightware.co.za >...

  • Page 5: Making Connections To The Sf11

    3. Making connections to the SF11 The SF11 gets power from either a regulated +5 V DC supply on the main connector or via the USB port when it is connected to a PC. There are analog, serial and I2C interfaces on the main connector and either one or a combination of interfaces may be connected to a host controller.

  • Page 6: Figure 5 :: Analog Voltage Connections

    In analog mode, the maximum distance over which the analog signal is linear can be set using menu item <j>. This allows for higher resolution if the SF11 is only used for low level flight. In alarm mode, the same setting is used as the switch point for the alarm.

  • Page 7: Figure 7 :: I2C Interface Connections

    “slave” mode and uses 3.3 V logic levels. The I2C address can be set through the USB menu system. The host controller acts as the I2C “master” and sends the address to the SF11 as an 8 bit value (7 address bits plus 1 read/write bit). The SF11 then returns the altitude as a 16 bit integer.

  • Page 8: Menu Options

    -10.00 meters to +10.00 meters and this value is subtracted from the altitude reading before it is made available on any of the interfaces. The zero datum offset can be used to compensate for the mounting position of the SF11 in the airframe, where distance readings may best be interpreted from a suitable point on the landing gear, rather than from the front face of the SF11.
  • Page 9 Menu item <h> is used to expand or hide the analog and alarm menu. The settings available in this menu relate to the linear analog voltage output and the alarm. SF11 Laser Altimeter - Product Manual - Revision 6 © LightWare Optoelectronics (Pty) Ltd, 2016...

  • Page 10: Figure 9 :: Altitude Represented By Distance (Serial / I2C) And Analog Voltage

    Do not use the entire measuring range if it is not needed. This value may also be changed using the serial port and I2C command set. SF11 Laser Altimeter - Product Manual - Revision 6 © LightWare Optoelectronics (Pty) Ltd, 2016...

  • Page 11: Figure 10 :: Alarm Settings

    ‘0’ state. The alarm switching point, output voltage range and the hysteresis can also be configured as described in the following sections. Figure 10 :: Alarm settings SF11 Laser Altimeter - Product Manual - Revision 6 © LightWare Optoelectronics (Pty) Ltd, 2016...
  • Page 12 Menu item <p> is used to set how long a lost signal is permitted before the out of range condition selected in menu item n: is applied. When operating close to the measuring limit of of the SF11 or over water, signals may be lost intermittently. Rather than jumping between the measured altitude and the out of range condition, this menu item can be set to hold the last valid altitude for the entered time.

  • Page 13: Figure 11 :: Median Filter Response Graph

    <r> ?FS 8<CR><LF> size = a Median filter size 3 ... 32 #FS,8<CR><LF> .write(27, a) write #FS,8 8<CR><LF a = 3 .. 32 SF11 Laser Altimeter - Product Manual - Revision 6 © LightWare Optoelectronics (Pty) Ltd, 2016...

  • Page 14: Instructions For Safe Use

    Make sure that the SF11 is switched OFF before looking into the lenses. The SF11 should be mounted using the four holes provided in the circuit board. Do not hold or clamp the lens tubes as this may cause damage and adversely affect the laser safety rating.

  • Page 15: Appendix A :: Specifications

    51 millimeters Beam divergence 0.2° Operating temp. 0 ... 40°C Approvals FDA: 1630995-000 (2016/09) Appendix B :: Dimensions Figure 13 :: Dimension drawings of the SF11 SF11 Laser Altimeter - Product Manual - Revision 6 © LightWare Optoelectronics (Pty) Ltd, 2016...

  • Page 16: Appendix C :: Main Cable Type 1, 35 Cm

    SF11 Laser altimeter Product manual Appendix C :: Main cable type 1, 35 cm SF11 Laser Altimeter - Product Manual - Revision 6 © LightWare Optoelectronics (Pty) Ltd, 2016...

  • Page 17: Appendix D :: Connecting To Pixhawk Autopilot Using "Serial 4

    Appendix E :: Electromagnetic interference (EMI) graphs The SF11 family has been tested for radio frequency interference in accordance with MIL-STD-451C. The results are well within the required limits so that neither direct radiation nor secondary radiation from wiring should cause interference to on-board systems such as GPS and optical flow.
  • Page 18 SF11 Laser altimeter Product manual 2. 14 kHz to 1 GHz - broadband 3. 1 GHz to 10 GHz - narrowband SF11 Laser Altimeter - Product Manual - Revision 6 © LightWare Optoelectronics (Pty) Ltd, 2016...

  • Page 19: Appendix F :: Command Set

    ?LN 4.5<CR><LF> noise = (a*256+b)/100 .write(4) .read(a) read ?LF 1<CR><LF> laser control = a Laser control #LF,1<CR><LF> .write(5,a) write #LF,1 1<CR><LF> a = laser control SF11 Laser Altimeter - Product Manual - Revision 6 © LightWare Optoelectronics (Pty) Ltd, 2016...

  • Page 20: Revision History

    SN: S11-10345 and S11-10351 onwards. Change of default I2C address from 0x55 to 0x66 to improve compatibility with PixHawk (page 7). Include the the caution “Ensure that a unique I2C address is assigned to the SF11/C and that no other devices share this address” (page 7). Rev 4 2016/05/19 TLP Updates to this document revision are applicable from SF11/* firmware revision 1.2,...

Table of Contents