Gotting HG 73840ZB Operating and installation instructions

Device Description HG 73840ZB
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Optical Line Tracker for 2
Cameras
CANopen® — serial — parallel port
HG 73840ZB
English, Revision 06 Dev. by: W.M.
Date: 12.07.2011 Author(s): RAD / SIS / L.S. / S.M.
Götting KG, Celler Str. 5, D-31275 Lehrte - Röddensen (Germany), Tel.: [phone] / 80 96 -0,
Fax: [phone] / 80 96 -80, eMail: [email protected], Internet: www.goetting.de

Content HG 73840ZB
English, Revision 06, Date: 12.07.2011 2
Content
1 Introduction.......................................................................5
1.1 Tracker................................................................................... 5
1.2 Track Detection ...................................................................... 5
1.3 Barcode.................................................................................. 6
2 Commissioning..................................................................8
2.1 Presettings ............................................................................. 8
2.2 Track Detection ...................................................................... 8
2.3 Leaving the Main Course ........................................................ 9
2.4 Additional Commissioning Steps ............................................. 9
2.5 Improving the resolution........................................................ 11
2.6 Design of the barcode........................................................... 11
2.6.1 Structure of the 2/5 interleaved barcode....................................... 11
2.6.2 Width of the barcode label ........................................................... 12
2.6.3 Length of the barcode label ......................................................... 12
2.6.4 Inverse track ............................................................................... 12
2.6.5 Position ....................................................................................... 12
3 Hardware ........................................................................13
3.1 Casing.................................................................................. 13
3.2 Block Diagram ...................................................................... 13
3.3 Pin Allocations...................................................................... 14
3.4 Control LEDs ........................................................................ 16
3.5 Operation with CANopen® Interface...................................... 16
3.6 Operation with serial interface (RS 232) interface.................. 17
3.7 Operation with digital/analog interface................................... 17
4 Software / Parameter Settings .........................................19
4.1 Terminal program ................................................................. 19
4.1.1 Locate HyperTerminal / Add to the system .................................. 19
4.1.1.1 Until Windows 2000 ................................................................ 19
4.1.1.2 Windows XP or higher............................................................. 19
4.1.2 Parameter Settings ...................................................................... 20
4.2 Using the configuration program ........................................... 20
4.3 (I)mage Settings ................................................................... 24
4.4 (O)utput-Input Settings ......................................................... 26
4.5 C(A)N-Menu ......................................................................... 28
4.6 (V)24 or Serial Menu............................................................. 29

Content HG 73840ZB
English, Revision 06, Date: 12.07.2011 3
4.7 Barcod(e) Menu .................................................................... 29
4.8 Luminance Histogram ........................................................... 30
4.9 (D)ata of Video Line.............................................................. 31
4.10 (K) Covariance Values .......................................................... 32
4.11 (P)ixel Correction.................................................................. 32
4.12 (M)aintenance ...................................................................... 35
4.12.1 Print (C)SV Values ...................................................................... 35
4.12.2 (W)rite User Parameters to Screen .............................................. 35
4.12.3 (I)mport User Parameters from Host to Antenna / (E)xport User
Parameters from Antenna to Host ................................................ 36
4.12.4 {S}ervice Menu ............................................................................ 36
4.12.5 [F]irmware Update ....................................................................... 36
4.12.5.1 Installation of the flash program .............................................. 36
4.12.5.2 Using the flash program .......................................................... 37
4.12.6 [D]efault Values to EEProm.......................................................... 37
5 Data Interface CANopen® ...............................................38
5.1 Description of the Process Data Object (PDO)....................... 38
5.1.1 TxPDO ........................................................................................ 38
5.1.2 RxPDO........................................................................................ 39
5.2 Heartbeat ............................................................................. 39
5.3 Node Guarding ..................................................................... 39
5.4 Description of the Service Data Objects (SDOs) .................... 39
5.5 Object Index ......................................................................... 40
5.5.1 Communication specific Entries within the Range of 0x1000 to
0x1FFF ....................................................................................... 40
5.5.2 Manufacturer specific Entries starting at 0x2000........................... 42
5.5.3 Standardized Device Profile higher than 0x6000........................... 42
5.6 CANopen® Directory............................................................. 43
5.6.1 Device Type ................................................................................ 43
5.6.2 Error Register.............................................................................. 43
5.6.3 COB-ID SYNC message .............................................................. 43
5.6.4 Device Name............................................................................... 43
5.6.5 Hardware Version ........................................................................ 43
5.6.6 Software Version ......................................................................... 44
5.6.7 Save Parameter........................................................................... 44
5.6.8 Restore Default Parameter .......................................................... 44
5.6.9 Producer Heartbeat Time............................................................. 45
5.6.10 Identity Object ............................................................................. 45
5.6.11 Receive PRO_1 Parameter .......................................................... 45
5.6.12 Mapping RxPDO_1 ...................................................................... 46

Content HG 73840ZB
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5.6.13 Transmit PDO_1 Parameter ......................................................... 46
5.6.14 Mapping TxPDO_1 ...................................................................... 47
5.6.15 Manufacture Parameter ............................................................... 48
5.6.16 Codes for System Configuration (delivered in PDO_1).................. 48
5.6.17 Manufacture Parameter - Node Parameter ................................... 50
5.6.18 8 Bit Digital Input (transmission in TxPDO1) ................................. 50
5.6.19 16 Bit Status (transmission in TxPDO 1)....................................... 51
5.6.20 16 Bit Analog Inputs (transm. in TxPDO 1) ................................... 51
5.7 EDS Configuration File ......................................................... 51
6 Serial Interface................................................................52
6.1 Telegram Structure (Optical Line Tracker -> Host)................. 52
6.2 Telegram Structure (Host -> Optical line tracker) ................... 53
7 Troubleshooting ..............................................................56
8 Technical Data ................................................................57
8.1 Optical Line Tracker.............................................................. 57
8.2 Ordering Information............................................................. 58
9 Appendix.........................................................................59
A Accuracy .......................................................................................... 59
10 List of Figures .................................................................60
11 List of Tables ..................................................................61
12 Index ..............................................................................63
13 Handbook Conventions....................................................64
14 Copyright and Terms of Liability ......................................65
14.1 Copyright.............................................................................. 65
14.2 Exclusion of Liability ............................................................. 65
14.3 Trade Marks and Company Names........................................ 65

Introduction HG 73840ZB
English, Revision 06, Date: 12.07.2011 5
1 Introduction
1.1 Tracker
This document describes the Optical Line Tracker (interpreting unit) G 73840ZA which
is part of an Optical Guidance System for Automated Guided Vehicles (AGV) enabling
travelling along a contrast line on the ground. The Optical Line Tracker interprets the
location of this line within the view of the camera and outputs its position with regards
to the center of the produced picture. In addition, it is possible to detect branchings
from the original course. The Optical Line Tracker is made for the connection of two (2)
PAL standard video cameras with composite video signal, in order to automatically
guide a vehicle in two different directions of travel (forwards and backwards). It in-
cludes a video multiplex unit. It is possible to connect a video monitor in order to con-
trol the detected track/line. The detected track is indicated on the display. In addition,
an LED line indicates the location of the guidance line.
An optical track guidance is only suited for an application in which a minimum level of
cleanliness is guaranteed.
The firmware 73840A12.01 described in this documentation includes the decoding of
a 2/5 interleaved barcode. Decimal encoding can range from 0 to 99 — a code analysis
will not be carried out. The barcode provides a high-density information. Thus it is pos-
sible to limit the barcode width nearly to the track width.
The Optical Line Tracker is located inside a top hat rail casing. The suitable cameras
HG 73841ZA inside an M30 industrial casing with M12 connector are available from
Götting KG. 
The data output is generated via:
-CAN-bus. A CAN open protocol (Device Profile DS 401) has been implemented.
-Serial interface with an adjustable transferable parameter.
-PLC interface with parallel inputs / outputs as well as an analog ’track offset' sig-
nal with a max. range of ±10 V is available. Offset and amplitude of this voltage
are adjustable.
The power supply of the cameras is generated via the built-in DC/DC converter. Out-
put voltage for the camera supply is 12 V.
The parameters of the Optical Line Tracker are either set via a serial interface using a
commonly available terminal program (e.g. Hyperterm) or via the various SDOs of the
CAN open protocol.
This description is valid for hardware version 73840ZA4 and software version 73840A3
2.01.
1.2 Track Detection
The video signal is imported with a resolution of 500 pixel per line. It is possible to se-
lect interpretation lines between the lines 30 and 255, as only these lines offer a useful
picture content. Up to 15 consecutive lines can be combined. The update rate for
each half-picture is 20 ms.

Introduction HG 73840ZB
English, Revision 06, Date: 12.07.2011 6
For the detection of the track, a static procedure that compares the relevant selected
lines of the camera picture with a model track of predefined width, is used. The degree
of compliance is important. The higher the degree of compliance with regards to the
width and contrast of the line, the higher the so-called covariance value. If the covari-
ance value exceeds a threshold determined during the commissioning of the system,
the track becomes valid and the location of the covariance maximum is converted into
a deviation value.
In case there are two maxima the location of the stronger maximum is used for the cal-
culation of the track deviation. If there are two or more maximas and branching is
planned, the locations of the two biggest maxima are used. For the calculation of the
deviation, depending on the indicated branching mode, the right or left maxima are
used accordingly. Afterwards two different sets of parameters can be used for each of
the two connectable cameras.
NOTE! For each optical image processing a constant lighting for good
results is required. Because of this, environmental light and its
reflection on the ground have to be shielded from the camera. A
shining/reflective dark track or background are also not good for
the camera for track detection.
1.3 Barcode
The following picture shows the recording of a track with an additional barcode. The
record was taken with a Frame Grabber, which is connected to the monitor exit of the
line tracker.
Figure 1 Track with barcode
The calculated track deviations will be displayed in combination with the covariance
values.
The code is read form the first and last line of the track marker, then it is decoded and
compared. If the codes match, it will be checked whether the minimal symbol contrast
exceeds the set threshold SCmin or not.
track marker
Rest areas
track
2/5 interleaved,
Barcode, 2-digit

Introduction HG 73840ZB
English, Revision 06, Date: 12.07.2011 7
If those conditions are fulfilled, so code is transferred in the TPDO of the CANopen®
protocol. Furthermore the bit CODE_OK is set in the system status. If the outputs
OUT_1 to OUT_4 are activated to proceed a parallel output of the code, the four lower
bits will be out put using those. So only the codes 0 to 15 can be put out using the
parallel port.
The output OUT_5 (DATA_READY) is always set for a certain time as soon as a code
is decoded, it does not matter if the parallel output is activated or not.
A new pulse is only possible after changing a code, to prevent a multiple
Data_Ready_Pulse, for example due to dirt etc. on a label.
To let the device read the same label again, for instance after changing the driving di-
rection, the following options are provided:
-Parallel port: the inputs IN_1 and IN_2 have to be set to 0 for a moment
(here it has to be taken care of the adjusted debounce time, see picture 13
on page 27).
-CANopen®: a communication reset has to be proceeded.
-Serial interface: A configuration sequence has to be produced.
After that the code which was read previously generates again a Data_Ready pulse
and the bite CODE_OK in the status is set again.

Commissioning HG 73840ZB
English, Revision 06, Date: 12.07.2011 8
2 Commissioning
2.1 Presettings
The CAN baud rate is set to 125Kbaud, the Node ID is preset to 1. The interpreter is
preset to a track width of 24 mm (dark track on light background) and 100 mm reading
distance for the camera G 73841. The thresholds for signaling deviation are set to
±10 mm and ±15 mm. The parallel interface is deactivated.
The presettings can be altered using either a terminal program (e. g. Hyperterm on
your PC) or via the various SDOs of the CANopen® protocol (also refer to section 4 on
page 19 and 5 on page 38).
2.2 Track Detection
In order to assure a reliable track detection, it is essential that the contrast of the line
on the ground compared to its environment is significant. Due to the signal processing
respectively the integrated filter, the system is able to bridge a short-time drop out of
the track, depending on duration of the drop out and the velocity. Shadows and light
beams may have significant influence on the performance of the system as the track
recognition may be impaired. It is, for example, possible that a combination of shad-
ows and light beams simulates a virtual guidance that may be followed by the vehicle.
Therefore it is recommended to ensure that the guidance line is protected from exter-
nal light using an appropriate cover (not included in this scope of supply).
In order to avoid reflections from reflective or sealed surfaces, the cameras should be
mounted with an inclination of 15 to 20oin direction of travel.
Figure 2 Recom. inclination of the camera in case of reflective surfaces
The max. width of the guidance line depends on the used camera lens as well as on
the height above the guidance line at which the camera is installed. The width of the
guidance line is ideal once its width on the control display is between 1/6 and 1/3 of
the overall width of the display. There are two options for the guidance line: dark on
light surface or light on dark surface.
opticalaxis
to
Installation height

Commissioning HG 73840ZB
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2.3 Leaving the Main Course
In case a vehicle has to leave the main course, the ancillary track has to start as shown
in Figure 3. In addition to the main course, only one ancillary track may be within the
view of the camera. It is therefore essential to locate the branch-offs on the right and
left side with an offset at places where two courses cross.
The instruction to leave the main course in order to get to one of the ancillary tracks
can be given either by the track selection input serial or by using the CAN bus.
This instruction is to be set just before the branch-off gets in sight - and to be reset just
after the branch-off has disappeared from sight.
Figure 3 Structure of branch-offs and crossing tracks
2.4 Additional Commissioning Steps
Use the built-in parameter menu for setting the parameters (refer to chapter 4 on page
19). Offset and deviation of the analog output voltage are adjustable in steps of 20 mV
using the menu (O)utput-Input Settings. For the exact setting, it is necessary
to check the output voltage with a voltameter.
Place the camera at the final installation height above a section of the guidance line
with bad quality and set straight forward travel.
-Enter the reading height and track width in millimeters in the menu Image Set-
tings. In case the camera G 73841ZB is used, the calibration factor is already fac-
tory-set. For other cameras, it is necessary to re-determine the calibration factor
within the submenu Adjust width of track (refer to Figure 11 on page 25).
-Also select the track structure in this menu: black on white or white on black.
-If different sets of parameters are to be used, those sets have to be entered here
or in the corresponding SDOs of the CANopen® protocol. For each set of param-
eters different inputs are possible when using the following variables:
Branch 1
“Sight window“ of
the sensor
Feed in
Branch 2

Commissioning HG 73840ZB
English, Revision 06, Date: 12.07.2011 10
-in the menu Image Settings (see 4.3 on page 24) the sub menus
Startline / Inverse Track / Width of Track / Height of
Camera / Peak Threshold / Warning Threshold / Calib-Fac-
tor / Luminance / Contrast / Gamma / X-Threshold for
Output 1,2 / X-Threshold for Output 3,4
For the ideal setting of the scan lines, a control monitor or a PC with frame grabber
card should be connected.
-Move the marker on the display (parameter Startline within menu Image
Settings, refer to section 4.3 on page 24) to a section of the picture without
reflections caused by the lighting of the camera or change the inclination of the
camera (refer to Figure 2 on page 8).
Read the peak value for the covariance function from the status line. As the chosen
sections is of very poor quality choose an input of approx. 90 % of this value for Peak
Threshold (refer to section 4.3 on page 24). Select the threshold for the guidance
line quality warning according to your requirements.
Now, go to the Luminance Histogram (refer to section 4.8 on page 30). The dis-
played picture should be similar to the one shown in the corresponding chapter. This
feature enables inspection of the brightness contrast of the picture. The further away
the narrow and high bars are located, the better the contrast. In case the bars become
thick and low, leaving no space in between them, the quality of the guidance line is not
sufficient. It is necessary to repair the guidance line.
The two following settings are only possible when using of the PLC interface:
•If necessary, adjust the interruption filter within the sub-menu Output-Input
Settings (refer to section 4.4 on page 26). The value of the interruption filter
indicates for how many pictures the track may disappear before the output OUT8
(track recognized) is deactivated. This value multiplied by 20 ms indicates the
duration of the tolerable interruption.
•Furthermore, this menu enables activation of a jump filter with reaction time. In
case the recognized track jumps more than the width of the track, this jump is
ignored if the value set under Bridge a track Jump is not equal 0. This num-
ber, multiplied by 20 ms is the duration of the reaction time. After this reaction time
period, the analog output gets closer to the existing value. The velocity of the
approximation is set under Jump Increment. The value 100 means the fastest
jump (20 ms) to the new value, while the value 1 means that 3000 ms are required.