Norac UC4+ User manual

Spray Height Controller
Improving the competitiveness of Industry and
Agriculture through Precision Measurement
Operators Manual
Version 6 - 2008

Printed in Canada
Copyright ©2008 NORAC Systems International Inc.
Reorder P/N: 446BC+MAN6+1 Revision A
NOTICE
NORAC Systems International Inc. reserves the right to improve products and
their specifications without notice and without the requirement to update
products sold previously. Every effort has been made to ensure the accuracy
of the information contained in this manual. The technical information in this
manual was reviewed at the time of approval for publication.

TABLE OF CONTENTS
1INTRODUCTION ....................................................................................................1
2OPERATOR SAFETY.............................................................................................2
3GENERAL SYSTEM DESCRIPTION...................................................................3
3.1 SOFTWARE ............................................................................................ 3
3.2 SENSORS ............................................................................................... 4
3.3 CABLES................................................................................................. 6
3.4 CONTROL PANEL................................................................................... 6
4SYSTEM OPERATION...........................................................................................7
4.1 POWER UP SEQUENCE........................................................................... 7
4.2 TYPICAL OPERATION ............................................................................ 8
5UNDERSTANDING YOUR UC4+ SYSTEM ......................................................13
5.1 UNDERSTANDING PERFORMANCE ISSUES ........................................... 13
5.2 UNDERSTANDING CROP MODE AND SOIL MODE ................................ 16
6SYSTEM SETUP....................................................................................................18
6.1 AUTOMATIC SYSTEM SETUP ............................................................... 18
6.2 RETUNE .............................................................................................. 26
6.3 MANUAL SYSTEM SETUP .................................................................... 27
6.4 QUICK INSTALL................................................................................... 35
7MAINTENANCE ...................................................................................................36
8TROUBLESHOOTING.........................................................................................37
8.1 GENERAL OPERATION......................................................................... 37
8.2 SENSOR RELATED ISSUES ................................................................... 40
8.3 HYDRAULIC RELATED ISSUES............................................................. 44
8.4 BOOM INSTABILITY AND MAIN LIFT ................................................... 48
9SYSTEM MESSAGES ...........................................................................................49
9.1 SETUP MESSAGES ............................................................................... 49
9.2 OPERATIONAL MESSAGES................................................................... 51
10 STATEMENT OF LIMITED WARRANTY .......................................................53
11 SPRAYER TYPES .................................................................................................54
12 MENU STRUCTURE ............................................................................................55

1
1 INTRODUCTION
Congratulations on your purchase of the NORAC UC4+ Spray Height Control
System. The system is manufactured with top quality components and is
engineered using the latest technology to provide operating features and
reliability unmatched for years to come.
When properly used, the UC4+ Spray Height Control system can provide
protection from sprayer boom damage, improve sprayer efficiency, and ensure
chemicals are applied correctly.
This manual is intended to be used in conjunction with the:
•UC4+ Quick Guide
•UC4+ Installation Manual
The manual provides a general description of the spray height control system,
a section regarding system operation, and discussion related to understanding
performance issues. Also provided are instructions for the use of the control
panel, information regarding system setup, regular maintenance and
troublshooting.
Please take the time to read the complete manual before attempting to use the
system. Although the UC4+ Spray Height Control system has been designed
for easy set up and use, a thorough understanding of the information provided
will ensure that you receive the maximum benefit from the system.
If you have any questions or comments regarding the operation of the UC4+
Spray Height Control system, please contact NORAC at any of the numbers
below. If you require service, phone us or visit our web site for the location of
the NORAC Service center nearest to you.
Phone: [phone] in Canada (Toll Free)
1-866-306-6722 in the United States (Toll Free)
0-800-404-8389 in the United Kingdom (Toll Free)
1-306-664-6711 all other regions
E-mail: [email protected]
Web Site: www.norac.ca

2
2 OPERATOR SAFETY
DANGER
Always ensure that the UC4+ Spray Height Control
system is powered down or in MANUAL mode:
•Before leaving the operator’s seat
•While the machine is not moving
•When transporting the machine
Under no circumstances should any service work be
performed on the machinery while the UC4+ Spray
Height Control system is in the AUTOMATIC mode.
Before working on any part of the booms:
•Set the UC4+ System to MANUAL mode
•Turn the sprayer engine off
Do not operate this system before:
•Reading and understanding the Operators Manual
•Thoroughly understanding your machine operation
The UC4+ Spray Height Control system will greatly
improve your spraying height accuracy and protect the
boom against damage in a wide variety of field conditions.
However, under some circumstances performance may be
limited. The OPERATOR of the sprayer must remain
ALERT at all times and override the automatic control
when necessary. Refer to the warranty statement in
Section 10 for more details.

3
3 GENERAL SYSTEM DESCRIPTION
Figure 1 shows the general layout of the UC4+ Boom Height Control system.
The function of each of the major system components is described in this
section.
NOTE: Some kits may not include all of the components shown.
Figure 1 - System Components and General Location
For more information on each component, please refer to the UC4+
Installation Manual and UC4+ Quick Guide.
3.1 SOFTWARE
The information in this manual applies to systems with Version 6 UC4+
control panel software. When the panel is turned on, the software version
and revision will be displayed for a few seconds as described in Section 4.1.
If your control panel does not display a version when it is turned on, your
software is Version 1 (all revisions).
All UC4+ control panels can have their software upgraded for a nominal fee.
It is recommended that all panels with earlier software be updated to the
current software version. Contact your local dealer or NORAC for more
information.

4
3.2 SENSORS
Three sensors are provided with your UC4+ boom control kit (with the
exception of certain kits). The sensors use an ultrasonic signal to measure the
distance to the ground, or the top of the crop. Three sensors are required to
provide good overall height management of the boom. Two sensors are
mounted on the outer sections of each wing (Figure 2). These sensors
maintain each wing at the set target height independently.
Figure 2 – UC4+ Sensor and Mounting Bracket
The third sensor (if applicable) is mounted on the main (center) boom
section. The main boom sensor is useful for setting your initial spray height
when you begin spraying in a field.
It is true that the main boom height will not change much, in consistent soil
conditions, since both ends of the main boom follow the height of the power
unit. However, it is extremely difficult to judge the boom’s actual height
accurately from the cab. It is also very difficult for the operator to see the
main section nozzles. It is common for operators to be in error from 20 to 30
cm (8 to 12 inches) or more (How often does the operator check nozzle
height with a tape measure?). The UC4+ control panel will give you an
actual height reading in the cab, and allow active control to the desired
height.
Another good reason for the main boom sensor is that soil conditions change
along with the weight of the machine. As the sprayer tank fluid level
changes throughout the day and soil conditions vary, the main boom height
will change because of the amount the tires sink into the soil.
Special attention must be taken into consideration when mounting the main
boom sensor, as explained in the UC4+ Installation Manual for your sprayer.

5
NORAC ultrasonic sensors are designed to work best in the brackets
provided (Figure 2). If you decide to use a different style of sensor mount,
you may limit the performance of the sensor and/or void your warranty.
Further, it is important to follow the guidelines in the UC4+ Installation
Manual for mounting the sensors. The sensors should be at least 25 cm (9
inches) above and 25 cm (9 inches) in front of the spray nozzles.
For large boom or severe terrain applications, an additional sensor may be
mounted near the midpoint of each boom to obtain an average height
reading. The average height reading will provide improved height control
over the length of the boom, and protect the boom in severe terrain
conditions (Figure 3).
POSSIBLE CRASH
WITHOUT ADDITIONAL SENSORS
CRASH AVOIDED
WITH ADDITIONAL SENSORS
Figure 3 – Severe Terrain – Additional Sensors Required
On sprayer models with main frame roll capability (Figure 4), the main
boom sensor can also be used to adjust the roll angle of the entire boom.
Alternatively, roll sensors can also be used to adjust the main roll angle of
the entire boom. Addition of this sensor to the UC4+ Spray Height Control
system can greatly improve the speed and stability of the automatic control
actions. Contact NORAC for more information on the availability of roll
control for your sprayer model.
Figure 4 – Roll Control of the Main Frame

6
3.3 CABLES
The power cable supplies 12 volt D.C. negative ground power to the control
panel and sensors. The system will function properly with a supply between
12 and 28 volts and may draw up to 10 amperes during normal operation.
The UC4+ control panel contains intelligent valve drive circuitry that helps
to protect the sprayer’s system against short circuits and other wiring
problems. However, it is still recommended to connect the UC4+ power
cable to a fused supply, that turns on and off with the ignition key of the
sprayer/tractor. For more information on cables, please see the UC4+
Installation Manual
3.4 CONTROL PANEL
The UC4+ control panel (Figure 5) is the main component of the UC4+
Spray Height Control system. The control panel uses the readings from the
ultrasonic sensors to control solenoid operated valves that in turn adjust the
boom height. The control panel will:
(1) indicate when the system is in AUTOMATIC or MANUAL mode,
(2) indicate any hydraulic action which is underway
(3) accept input to adjust all control system settings.
Figure 5 – UC4+ Control Panel
LCD
SCREEN
+/- SWITCH
AUTO/MANUAL
SWITCH
POWER
SWITCH
SENSOR
DISPLAY/
SETUP
SWITCH

7
4 SYSTEM OPERATION
This section outlines the UC4+ Spray Height Control system’s features and
controls during field operation. Before you can operate your UC4+ Spray
Height Control system in AUTO mode, it needs to be configured either
automatically or manually. If your control panel shows the power up
sequence below and will allow AUTO mode, it has been configured. If
your panel shows different messages after being powered up or will not
allow AUTO mode, it will attempt to begin or resume Automatic System
Setup. Refer to Section 6 for System Setup instructions.
4.1 POWER UP SEQUENCE
The LCD screen messages shown below are displayed temporarily when
power is turned on to the UC4+ control panel. The system will always
power up in manual mode. Once the Normal Operating Screen is shown the
system is ready to use.
Table 1 – Power Up Screens
LCD Display Description
UC4 + UC4+ Control Panel
V. 6C Version 6 software
Type AN2 Sprayer Type: AN2. See Sprayer Types
on page 54 – for a list of types.
METRIC The panel is setup to display height in centimeters. This can
be changed to display inches.
* Nodes The control panel is looking for connected sensors.
3 Height Three height sensors are connected.
Allocate The control panel is preparing to set up each sensor.
Setup LO The control panel is setting up the Left outer (LO) sensor,
followed by the other sensors (LI, RO, RI, MR, ML).
Ready The control panel is ready to begin operation
M 75 M The Normal Operating Screen. This screen is shown until
input is received from the operator. (Sec 4.2.1)

8
4.2 TYPICAL OPERATION
4.2.1 Normal Operating Screen
The Normal Operating Screen provides information pertaining to the height
and mode of both booms. Figure 6 shows a typical Normal Operating
Screen.
Figure 6 – Normal Operating Screen
When a boom is in AUTO mode, indicated by an "A" in the control mode
portion of the screen, the UC4+ panel shows the target boom height. In
MANUAL mode, indicted by an "M" in the control mode portion of the
screen, the UC4+ control panel shows the average boom height reading.
In both AUTO and MANUAL modes, the screen will also show arrows to
indicate that the boom is being commanded to move. Table 2 explains some
examples of typical Normal Operating Screens.
Table 2 – Examples of Normal Operating Screens
LCD Display Description
A 89 A In AUTO mode, target average height is 89 cm (or inches
if selected)
A 89 A Left side taking corrective action upwards
A 89 A Right side taking corrective action downwards
89 A Main lift is taking corrective action downwards
A 89 Main roll section is taking action in the clockwise
direction
M 89 A Left boom in MANUAL mode
Right boom in AUTO mode with actual height of 89
M 89 M Booms are in MANUAL mode with actual height of 89
Operator is manually lowering the right boom
89 A Left and right booms are in AUTO and lowering
Main boom is in AUTO and lifting
4.2.2 Main Menu Overview
55 A
LEFT BOOM
MAIN LIFT TARGET HEIGHT
RIGHT BOOM

9
Table 3 – Main Menu Structure
Navigating past the end of the menu will return the control panel to the Normal
Operating Screen
More ? Toggle the "AUTO (YES)" switch to edit or view more sensor
settings.
88 () 67 Displays diagnostics information used by technical staff.
56 Displays the current main lift height, in the selected units.
55 55 Displays the current right boom heights, in the selected units, from left
to right.
55 55 Displays the current left boom heights, in the selected units, from left
to right.
M 55 M
SENSOR
DISPLAY Menu
↑
SENSOR DISPLAY
/ SETUP (NO)
Switch
↓
SETUP Menu
The Normal Operating Screen is usually
displayed. If no switch is toggled for 30
seconds, the LCD will revert to this screen.
From any menu prompt, if you toggle and hold
the "SETUP (NO)" switch for two seconds, the
control panel will return to this screen.
Sensi 5 Displays the current control sensitivity setting. A higher number
results in a quicker response. Range is from 1 to 10.
Soil ON
Use the " +/- " switch to set the sensor target to SOIL or CROP
mode.
ReTune? The ReTune will optimize your system for the best performance
possible. This will take from one to three minutes. (Section 6.2)
More ?
Toggle the "AUTO (YES) " switch to edit or view more control
settings.
Navigating past the end of the menu will return the control panel to the Normal
Operating Screen

10
4.2.3 Using the Toggle Switches
All functions on the UC4+ control panel are activated using its three toggle
switches. To access either the SENSOR DISPLAY or SETUP menus,
make sure you are at the Normal Operating Screen. To adjust the setting of
individual menu items, use the " +/- " switch while the item is displayed.
•New settings take effect once the Normal Operating Screen is displayed
Figure 7 – Normal Operating Screen
Menu items will time out and return to the Normal Operating Screen after 30
seconds. If you wish to return to the Normal Operating Screen sooner,
toggle and hold the "SETUP (NO)" switch for two seconds. Any new
settings will take effect once the Normal Operating Screen is displayed.
If you wish to lock the sensor height readings on the screen indefinitely,
toggle the " +" switch once while viewing the desired sensors.

11
4.2.4 Changing to AUTOMATIC or MANUAL Mode
You can change between MANUAL and AUTO with the "AUTO (YES) /
MANUAL" toggle switch. Ensure you are at the Normal Operating Screen.
When the UC4+ is in MANUAL mode, the boom may be controlled as
usual with the boom control switches on the sprayer’s multifunction
handgrip.
When the UC4+ is in AUTO mode, operating the sprayer's left or right
boom control switches will immediately cause that boom to revert to
MANUAL mode. The sprayer (joystick) switches will override automatic
boom height control on either the left or right side. The "AUTO (YES)"
switch must be activated to return that boom to AUTO mode.
The sprayer's main lift control (main up or main down) switches provide a
target height adjustment feature (Section 4.2.5). If you press and hold either
the main up or the main down switches for more than two seconds, the
UC4+ control panel will switch ALL booms (left, right, main, and roll) to
MANUAL mode. This feature provides a convenient method of switching
to MANUAL mode when folding the sprayer for transport.
4.2.5 Adjusting the Target Height (Setpoint)
Adjust the target height setting with the "+/-" switch while in AUTO mode.
The smallest target height setting allowed is called the minimum height
override. The default minimum height settings are programmed before
shipped from the factory.
NOTE: The minimum height settings are adjustable. – If you wish to
adjust them, please contact NORAC for details.
You can also adjust your main boom target height by pressing the sprayer's
main lift control switches. Each press of the up switch will increase the
target height by one unit. Each press of the down switch will decrease the
target height by one unit.
4.2.6 Viewing the Actual Boom Height
Toggle the "SENSOR DISPLAY" switch to view the actual boom heights.
This height is from the nozzles to the ground. This menu will show you the
left, main (center), and right boom heights. Toggle the "SENSOR
DISPLAY" switch again to view additional sensors if they are installed.
You can view the height menus in both AUTO and MANUAL modes.

12
4.2.7 Changing the Sensitivity of the System
The Sensitivity (Sensi) setting (Section 5.1.1) can be adjusted in both
MANUAL and AUTO modes. Toggle the "SETUP (NO)" switch to view
the current Sensi setting. While viewing this menu, toggle the "+/-"
switch to adjust the value.
A lower number will reduce the system sensitivity and improve stability.
Increasing the number will speed up the response.
Five is the normal setting. At the start of operation, before the sprayer is
warmed up, a lower Sensi setting may be required for stable control. As
the sprayer warms up, increase the Sensi setting up until the performance
reaches an optimum level.
4.2.8 Changing Between SOIL and CROP Mode
The SOIL or CROP mode (Section 5.2) setting can be adjusted in both
MANUAL and AUTO modes. Toggle the "SETUP (NO)" switch twice to
view the current setting. While viewing this menu, use the " +/- " switch to
change between SOIL and CROP mode.
4.2.9 Changing between Inches and Centimeters
The panel can be changed to display either centimeters or inches. Toggle the
"SENSOR DISPLAY" switch until the LCD screen says "MORE ?".
Toggle the "YES" switch once and then toggle the "SENSOR DISPLAY"
switch until the LCD screen displays "OTHER ?". Toggle the "YES"
button and then use the "+/-" switch to change between CM and INCHES
mode.

13
5 UNDERSTANDING YOUR UC4+ SYSTEM
5.1 UNDERSTANDING PERFORMANCE ISSUES
Your UC4+ Spray Height Controller will work well in most situations.
However, as with any equipment, it is important that the operator remains alert
at all times. There may be some field and terrain situations where performance
is diminished. In these situations the operator must resume height control of
the booms manually. A discussion of performance issues is given below to
help clarify these situations.
5.1.1 Sensitivity (Sensi) Setting
The UC4+ Spray Height Control system is configured to work well in most
conditions, with warm hydraulic oil, at a sensitivity (Sensi) setting of five.
When you first begin operation at the start of a day, it may be necessary to
operate at a lower sensitivity until the oil has reached normal temperature.
Keep increasing the Sensi setting until the performance is optimized.
Different types of terrain may require different Sensi settings. The
Sensi setting controls more than just response time. It also determines
how accurately the UC4+ Spray Height Control system will try to correct for
height errors. The higher the sensitivity the higher the accuracy. At low
sensitivity a few cm/inches of error will be tolerated. At high sensitivity,
virtually no error will be tolerated. Therefore, the system will be much more
active at high sensitivity than at low sensitivity.
NOTE: Field conditions and operator preferences determine the
appropriate Sensi setting. On some sprayer models, it may
be difficult to reach an optimum level of sensitivity while
maintaining good boom stability. This could be an indication
that the boom is mechanically under-damped for control
purposes. Additional shock absorbers/dampers can
dramatically improve automatic control performance. Some
UC4+ kits come complete with additional damper kits. Other
sprayer models have damper kits available from the sprayer
manufacturer or from NORAC as optional equipment.
Contact NORAC or your sprayer dealer for more assistance.
5.1.2 Boom Reaction Time
There are two key factors that determine how quickly your boom can react to
changes in terrain. The first factor is the available hydraulic speed. The
maximum hydraulic speed of your boom was designed by the sprayer
manufacturer and is not improved or diminished with the addition of the
UC4+ height control system.

14
The second factor is the mechanical design of the sprayer. The Sensi
setting does affect the reaction time of your boom – the higher the number
the quicker the response. However, how high you can run the Sensi
setting is determined to a large extent by mechanical issues related to the
boom and sprayer.
Important design issues include the style of main boom mount (for example,
center pivot or nonparallel links), the amount of mechanical damping and
spring centering on the main boom mount, and whether a main boom roll
system is available on the sprayer. All of these factors together determine
the maximum Sensi setting you can run on your UC4+ Spray Height
Control system. This, in turn, will set the reaction time of the boom in a
given situation.
The UC4+ electronics are rarely the limiting factor in determining overall
automatic height control performance.
5.1.3 UC4+ over Ditches, Waterways and Outside Rounds
Many situations exist where one sensor may be reading over terrain that does
not accurately reflect the situation for the rest of the boom. For example, if
you are spraying along a waterway, it may be necessary to run the outer
boom sensor out into the waterway itself. This situation is similar to the
picture in Figure 3. In this example, the outer sensor will bring the boom
lower than desired and may put the mid-point of the boom at risk. Outside
rounds adjacent to very weedy areas or tall thick grass are examples of the
opposite situation.
In these situations the operator must remain alert and override AUTO mode
when necessary. Addition of the optional severe terrain (inner) sensors will
greatly improve performance in these situations.
5.1.4 Driving Through Ditches and Over Terraces
Changes in terrain that include driving over terraces or through ditches are
special performance cases. This type of terrain can cause the sprayer or
spray cart to pitch and roll significantly. Sprayer operation at speeds of 15-
30 km/hr (10-20 mph) in severe terrain may result in rapid changes in boom
tip height. In these situations, typical sprayer hydraulic systems are not
capable of tip speeds high enough to correct for the induced error.
There are two solutions to this problem. The first solution is for the operator
to recognize these situations before they occur and manually raise the boom
section(s) to a safe height. To return to AUTO mode, use the "AUTO
(YES)" switch.
The second solution is to add a roll control system to your sprayer (if one is
available). This type of system will compensate for the sprayer roll in this
situation and also add stability to your boom in normal operating conditions.

15
5.1.5 Sensing Further Ahead of the Boom
Installing the sensor farther ahead of the boom is not an acceptable solution
to any performance issues. The reason is that, as the sensor is moved further
ahead, there will be an increasing height error at the nozzles. In other words,
the sensor and nozzle are at two different points in space, thus introducing an
error for all but the most level terrain. In severe terrain, this height error can
bring the nozzles close to the ground as the sensor reads over the crest of a
hill, or down into a ditch.
5.1.6 Sensor Capabilities
In order for the UC4+ Spray Height Control system to work at its maximum
level of performance, the UC4+ sensors must be returning accurate height
readings at the designed frequency. Under typical conditions, the sensors
can provide accurate height readings from 9 inches to over 120 inches, and
return many height readings in one second. The target in SOIL mode can be
identified through stubble, young crops, row crops, and normal trash. The
target in CROP mode can be identified over cereal grains, specialty crops,
and row crops. See the next section for more information on CROP and
SOIL mode guidelines
There are two main steps to ensure sensor performance. The first step is
proper mounting. See Section 3.2 on page 4 for more information on sensor
mounting. The second step is to ensure that the protective foam covers on
the sensors are kept clean, and that the ultrasonic transducer behind the foam
does not become corroded or excessively dirty. Extra foam pieces are
shipped with your kit. The transducer is a maintenance item and can be
replaced at NORAC service locations. Transducers can last from three to ten
years, depending on conditions. Refer to Section 7 on page 36 and the
UC4+ Quick Guide for more maintenance information.
If the mouth of the sensor becomes wet, it is normal for the sensor to return
error messages until the transducer has dried off. This could include rain or
excessive overspray. Material can build up on the transducer if the sensor is
mounted too close to the spray nozzles. This is the reason that the sensor
must be mounted at least (25 cm) 9 inches in front of the nozzles. It keeps
the sensor housing out of the normal region of overspray.
In the sprayer boom application, the sensors ignore any target that is closer
than 25 cm (9 inches) from the bottom of the sensor housing. This region is
called the blanking range. Operating the sensor at heights near the blanking
range is dangerous and will affect performance because height readings can
be very intermittent. This is the reason that each sensor must be mounted at
least 25cm (9 inches) above the spray nozzles.

16
5.2 UNDERSTANDING CROP MODE AND SOIL MODE
A unique feature of UC4+ sensors is their ability to operate in CROP mode.
In this mode the sensor will track the first available sonic target. That is,
when positioned over standing crop, the sensor will return the average height
of the heads in a circular area below the sensor. In the same situation in
SOIL mode, the sensor will track the last available sonic target. That is,
signals from the heads, leaves, and trash will be ignored in favor of the
ground.
It is important to note that the targets must be available and of sufficient
strength for the sensor to "see" them. There may be some crop and terrain
situations that do not work well for CROP mode or SOIL mode. In these
situations the operator must resume height control of the booms manually.
In general, the addition of the severe terrain kit will improve performance in
CROP mode. All of the situations discussed below are lessened by the
addition of the extra sensors on the wings.
5.2.1 Areas of "No Crop" in CROP Mode
If, while operating in CROP mode, the sensor encounters an area where
there is no crop, the system will behave as follows. The sensor will track the
soil because only one target is available. The boom will lower as shown
below. Areas like this may include missed areas during seeding, alkaline
areas, and so on. When the problem area ends, it may not be possible for the
sensor to see the crop again unless the operator raises the boom manually.
The sensor may be closer than required 25 cm (9 inches) from heads of the
crop, thus blanking out the desired target.
"No Crop
Area"
Figure 8 – Area of “No Crop” When Operating CROP Mode

17
5.2.2 Boom Stability in Crop
In general the top of the crop is a more inherently variable target than soil.
To put it simply, given identical control settings, your height control would
be more active when operating in CROP mode than in SOIL mode. To
allow for this, many settings are customized automatically when you change
modes on the UC4+ control panel. This is designed to provide a more stable
response in CROP mode. The tradeoff is that the system will also be
slightly slower to respond in CROP mode than in SOIL mode.
5.2.3 Thin Crop
The UC4+ ultrasonic sensors operate by bouncing sound waves off the
desired target. A minimum signal level is required from the crop in order to
use it for control purposes. This is no different than the fact that your radio
must be at a certain minimum volume level before you can physically hear it.
Different types of crop, and crops at different stages of development return
varying levels of sound. The following are some general guidelines.
•Crops in growing stages are relatively good sonic targets.
•Bearded crops are relatively poor sonic targets.
•In row crops, the sensor must be positioned over the row to use the
crop signal, or between the rows to use the ground signal.
•The desired target must cover roughly 60 percent of the area to be
tracked consistently. That is, when looking at the ground, the heads
should cover about 60 percent of the ground. Otherwise, you can
use SOIL mode.
•If the sensor runs too close to the heads, they may not return enough
signal to be seen, or they may be blanked out. The nozzles must be
at least 55 cm (22 inches) from the crop. Slightly higher target
height settings will work better in thin crop.
5.2.4 Main Boom Sensor in Wheel Track
The required location for the main boom sensor is determined by the UC4+
Installation Manual for your sprayer and by the options you have installed.
Special attention is necessary when mounting the main boom sensor.
Mounting the main boom sensor directly behind a sprayer tire may impair
main lift control when operating in CROP mode. Height readings from crop
that is flattened by the sprayer wheel do not provide an accurate
measurement of canopy height, resulting in poor performance.