This document provides specifications and operating instructions for a single axis solar tracker controller. It tracks the sun's position using an internal calculation based on location settings, and controls an actuator motor to adjust the panel angle automatically throughout the day. It has inputs for wind speed sensor and manual override/stow commands. The controller calculates a target angle for the panel periodically based on sunrise/sunset times and controls the actuator to match this angle. It can be programmed with location details like latitude, longitude and time zone to customize tracking for the installation site.

1. Page 1 of 5 Single Axis Solar Tracker Controller
SINGLE AXIS solar TRACKER controller
With wind sensor input
Specifications:
Tracker:
1. Tracker principle: controls azimuth angle according to astronomical sun positioning
2. Tracking axis : single axis
3. Size : 170mm x 120mm
4. Input voltage : 24VDC
5. Enclosure : IP65 ABS grade.
6. Termination : IP65 graded ABS glands – 7 nos.
7. Output : 24V output to actuator up to 20A load.
8. Resolution : 0.1 degrees.
9. Axis angle : settable from 30 to 150 degrees.
10. Control action : automatic closed loop using signal from external inclinometer for angle feedback
11. Display : 16 x2 alphanumeric LCD display
12. Timing : Inbuilt using highly accurate RTC with independent battery backup.
13. Accuracy : < +/‐1 degrees.
14. Safety features : a. Reverse supply protection .
b. Over current protection for Load (internal fuse)
15. Manual override: Manual mode provided for manually adjusting the actuator during installation.
16. wind sensor input: 4~20mA input
17. wind sensor range: settable upto 1000km/hr.
18. alarm output: 1C/0 NO relay contact 5A rating.
19. stow Input: Digital input for manually setting the unit to stow mode.
20. Reset Input: Digital input for manually resetting the unit from stow mode.

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Principle of operation:
Tracker:
The single axis tracker is based on an internal dynamic calculation of the solar sunrise and sunset time
using the current real‐time and date from its inbuilt RTC and the latitude,longitude and timezone set by
the user for that location. After this data is achieved, it calculates the target angle of the panel and
controls the actuator load to achieve this angle. This control action is repeated for every specific time
interval from sunrise to sunset. Note that this unit does not depend on the time the actuator is ON but
instead tends to turn the panel to the correct angle. This ensures that even if there is any deviation of
the panel angle at any point of time due to external intervention OR through the manual mode of the
unit, the unit will recover the panel automatically in the next control cycle. The LCD display shows the
various important parameters like Time, Date, Target ‐angle/Target time,etc.( discussed in the next
section). The unit also provides setting of various parameters to the user through four keys on the front
panel thus making the unit extremely flexible and can be adapted by the user for different
environments much easily.
Note that the seasonal variations in the sunrise/sunset and hence the positioning of the panel at any
particular time is automatically calculated. So seasonal adjustment for the unit is not required.
Inclinometer unit:
The Inclinometer unit is separately enclosed in a small IP65 box and provides the signal to the main unit
about the current angle of the panels. So this box has to be mounted on the panel according to the
directions provided on it. To facilitate longer distance between the two units, the signal is converted
into a constant current source in the range of 8~20mA inside the inclinometer unit and is converted
back into the required angle reading inside the main unit.
Stow Input:
The Stow input provided inside the unit is basically used to manually set the unit into Stow mode and is
only valid when the unit is in normal mode. In the stow mode, the unit tends to move the panel in a
perfectly horizontal position of 90 degs. And will stop all automatic tracking operations once the mode
is initiated. This mode can be reset ONLY by pressing the Reset key or resetting the main power to the
unit.

3. Page 3 of 5 Single Axis Solar Tracker Controller
Setting the Tracker controller unit:
The target angle calculated by the unit depends upon the various settings of the unit like real time , date ,
latitude/longitude and the timezone of the region. So these parameters should be determined and inputted to
the unit before installing the unit on the structure. A detailed explaination of the various parameters is cited
below.
1. Date /Time: this parameter refers to the real time date and time of the region of installation.
The time is shown in format hh:mm:ss and the date is shown in the format dd:mm:yyyy.
Important: Note that the unit does not have any daytime adjustment provision. So adequate
adjustments should be made to input the standard time/date without daytime correction
when installing in specific countries where there is a daytime adjustment.
2. Latitude: This parameter refers to the latitude of the location of installation. The range of setting
would be +/- 90.00 degrees. Note that the sign of the latitude indicates whether the location is
located north or south of the equator. +ve implies North and –ve value implies South of the
equator . The latitude should be inputted in decimal form . So a value of say 76⁰30’ should be
inputted as 76.50 degrees.
3. Longitude: This parameter refers to the longitude of the location of installation. The range of
setting of this parameter is +/- 180.00 degrees. The sign of the longitude indicates whether the
location is situated to East or West of the prime meridian (Greenwich meridian). +ve implies East
of the meridian and –ve implies West of the meridian. Similar to latitude, the value is in decimal
form and should be determined and inputted accordingly.
4. Timezone: This parameter refers to the time zone of the region of installation. It should be in
relation to the Greenwich meridian Time (GMT). A positive value (e.g. GMT+5.50) refers to a
location East to the prime meridian and a negative value (GMT – 7.00) refers to a region west of
the prime meridian. This parameter increments in steps of 0.25Hrs i.e. 15 minutes.
5. Time interval: This parameter determines the periodic time interval in minutes during daytime
when the unit recalculates the next target angle/ target time and tends to bring the panel to the
present required angle. This parameter increments in steps of 5 minutes from 5 minutes to 90
minutes max. Note that lesser time interval leads to more accuracy but greater power
consumption by the actuator and vice versa in case of a larger time interval.
6. Wind sensor Range: This parameter determines the total range of the wind sensor connected to
the unit with respect to its 4~20mA output. It has a range upto 1000 counts.
7. Wind sensor limit: When the wind value exceeds this value , the stow mode is initiated after a
time delay. When the wind crosses this limit, the unit will wait for a specific time interval before
entering stow mode. If the wind decreases below this limit before this time interval, then the
unit will revert back to the auto mode. Range of this parameter is from 0 to wind sensor range.
8. Time Delay: As mentioned above, This parameter determines the time delay for the unit to
enter stow mode . This value is in seconds and has to be entered to avoid a false trigger of stow
mode due to occasional gusts of winds which are not threatening.

4. Page 4 of 5 Single Axis Solar Tracker Controller
Programming modes of the unit.
1. Normal mode: (Read only)
This is the default display mode of the unit on power ON. On the bottom left corner of the display, a
message “(S)” for scan and “(H)” for hold is displayed in this mode. In scan mode, the scrolling is
automatic and in hold mode , the user can manually move to the next or previous parameters using inc
and dec keys. To toggle between these modes, press SET key momentarily.
It scrolls the following sets of important data to the user to confirm the proper functioning of the unit.
a. Real‐ time and present angle
b. Sunrise and sunset time
c. Next target angle and time
d. start angle and end angle
e. wind speed and date.
2. Manual mode:
To enter this mode, press and hold SHF key for 8~ 12 seconds. The display will initially show
“Manual mode entering…” for 2 seconds and then continuously show the actual angle of the panel in
the bottom row. Now the user can manually inch the panel in the forward OR reverse direction by
pressing the INC and DEC key respectively. To exit this mode, just press and hold SHF key again for 3‐4
seconds until the message “manual mode exiting…” pops on the display.
This mode is recommended only during installation or general troubleshooting of the mechanical
structure of the panel and unit should be exited to the normal mode once work is over.
3. Program mode:
This mode is used for setting the various system parameters of the unit like time, date, time interval,
etc.
To enter this mode, press and hold SET key for 3‐4 seconds. To change the parameters, use the
SHF key to move highlight (blinking) within the parameter and then to increment /decrement the value
of the blinking value, press INC and DEC key. To save the present parameter and move to the next
parameter just press momentarily the SET key again. The various parameters and their functions are as
below:
a. “Set Date”: This is the current date of the unit in dd‐mm‐yyyy format
b. “Set Latitude”: This parameter is the Latitude of the location of installation of the solar tracking
system.
c. “Set Longitude”: This parameter is the Longitude of the location of installation of the solar tracking
system.
d. “Time Interval”: This determines the periodic time interval in minutes during daytime
When the unit recalculates the next target angle/ target time and tends to bring the panel to the
present required angle. This parameter increment in steps of 5 minutes from 15 to 90 minutes.
e. “Set Timezone”: The timezone of the region of installation (e.g.GMT+5.5 for India).
f. “Set Time” : This is the current real time of the unit in hh:mm:ss format. Note that it is the standard
time of the region and should be set accordingly.
g.”wind speed range”: the full scale range of the wind sensor connected.

5. Page 5 of 5 Single Axis Solar Tracker Controller
h.”wind speed limit”: The wind speed limit above which the stow mode is activated.
i.”time delay”: the delay in seconds for which the unit waits after wind speed exceeds limit value before
initiating stow mode.
To come out of the Program mode, press and hold SET key again for 3‐4 seconds. The unit
will revert back to the normal mode.
4. Installation mode:
This mode is required for calibrating the start position and end position of the panel in sync with the
unit. This ensures that the target angle to be achieved will not cross this limit while controlling the
panel. To enter this mode, follow the following procedure:
Press and hold INC key for more than 10 seconds The display will show “Calibration Mode entering” on
the display for 2‐3 seconds and then show “set start angle “ and actual angle on the display. Now inch
the panel to the start position using the INC and DEC key and press SHF key to accept the start angle. A
confirmation will be momentarily displayed “start angle accepted!” on the display and the display will
now show “set end angle”. Again move the panel to the required end angle using INC and DEC keys and
press SET key to accept the end angle. A confirmation”end angle accepted!” will be displayed
momentarily before the unit reverts back to the normal mode. Note that this mode is required only
once during installation of the panel on site and need not be set again. The start /end angle setting
ensures that the actuator is not pushed to its extreme ends.
STATUS LED DESCRIPTION:
The following LEDs on the front panel display the current status of the unit.
1. FORWARD : this red LED indicates that the unit is moving in the forward direction i.e. from east
to west.
2. REVERSE: this yellow LED indicates that the unit is moving in reverse direction i.e. from west to
east.
3. STOW: this red LED depictes that the unit has entered STOW mode. This mode can be initiated
by giving STOW input OR if wind sensor exceeds limit for more than the set time delay.
4. ALARM: this red LED indicates that the ALARM relay output is activated .
5. WIND: this yellow LED indicates that the wind input has crossed the limit. If the LED is blinking,
then the unit is waiting for the time delay to elapse and goes steady when it has elapsed.
6. OK: this green LED will glow steadily if there is no observable error in the operation of the unit.
IF the inclinometer is not connected, then the unit will still perform its basic operation and in
this case, this LED will be blinking.