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Sun Trackers

MS-700_DNI+MS-712_DNI+STR-32G_maxThe STR-series a compehensive range of compact single and double arm Solar trackers suitable to accomodate all kinds of solar radiometers. The heavy duty STR-32G is capable to handle 4 times the load of the STR-21G and 22G.   

EKO Sun Trackers are very compact, robust, relatively light weight and very power efficient. Inside the Sun Tracker a Harmonic Drive with advanced motion control unit is used on each output shaft. Harmonic drive is a leading drive technology for those application where high precision, durability, low backlash, high transmission ratios and torque is required. Due to its compact design and high transmission ratio small motors could be used to keep the power consumption low. 

EKO has a long tradition manufacturing fully automatic meteorological Sun Trackers which are used to accurately position solar sensors (Pyrheliometers, Pyranometers, Pyrgeometers) towards the sun, either to expose or shade a sensor from the direct sun beam. In combination with a pyrheliometer (DNI sensor), shading assembly and Pyranometer, respectively the direct and diffuse radiation component can be measured. Using the sum component calculation method the global radiation can be accurately determined when the 2 components are added (Cosine zenith angle x (Direct) + Diffuse).

The maximum payload is tuned to use several solar sensors to measure direct, diffuse and global radiation. To measure diffuse radiation a shading ball assembly is required in combination with the double arm STR-22G. To put 2 sensors in the shade a double shading ball version is available.

Nowadays all the STR-Sun Trackers have a built in GPS receiver for easy installation and accurate sun tracking. During automatic set up the position coordinates and time information is used to calculate and control it to the exact sun position. The standard sun sensors compensates for any geometrical misalignment and due to this makes the measurement more precise.

Models

Product Model Description
STR-21G Sun Tracker

STR-21G Sun Tracker

The compact sun tracker are perfectly suited to support all kinds of Global, Diffuse and Direct Radiation …

STR-22G Sun Tracker

STR-22G Sun Tracker

The compact sun tracker are perfectly suited to support all kinds of Global, Diffuse and Direct …

STR-32G Sun Tracker

STR-32G Sun Tracker

The heavy duty Sun Tracker STR-32G completes the extensive EKO Sun Tracker range and is capable to …

Specifications

Model

STR-21G

Single Arm

STR-22G

Double Arm

STR-32G 

Double Arm

Motor
Stepping motor  
Motor driving mode
Half step 
 
Driving technology
Harmonic Drive
Pointing accuracy
< 0.01° (Solar Elevation: 0 to 87°)  
Angle resolution
0.009°
0.009°   0.0036°
Rotation angle
Elevation-angle(-15° to +95°)
Azimuth-angle(0° to +/-180°)  
Torque
12 Nm
24 (12+12) Nm
60 (30 +30) Nm 
Payload
7kg balanced
20kg balanced
 60kg balanced
Tracking mode
Sun-sensor mode and Calculation mode are automatically switched.  
Tracking accuracy of Sun-sensor mode
+/- 0.01°
  
Sun-sensor field of view
+/- 15°  
GPS Receiver Integrated receiver
GPS Sensor measurement accuracy
Horizontal Position: Below 15m (2drms). GPS Positioning
  
GPS Sensor positioning start time
< 5min. (depends on the recieving condition.)
  
LED Indicator
Power, GPS status  
Environmental Protection
IP65  
Temperature range
From -30 to +50°C  
Altitude for solar position calculation
No Limitation
  
Communication
RS-232C, 9600bps, 8N1
  
Power requirement
AC100 to 240V, 50/60Hz, 50W

 AC100 to 240V, 50/60Hz, 50W
  DC21 to 32V, 20W for DC optional Sun Tracker (*Power consumption 10W)
Dimension
430(W) x 380(D) x 440(H) mm 
430(W) x 380(D) x 250(H) mm 
Weight
14.5 kg
15.5 kg
15 kg 
Sun sensor Integrated with Sun tracker
Pyrheliometer mount Standard Standard Optional
Levelling tripod Standard Standard Optional
Diagnostics and control software Standard

*Power consumption under normal load and operating conditions @ 25°C.

 

Applications

DNI measurements at CPV sites

DNI measurements at CPV sites

Concentrating Photovoltaics (CPV) is driven by only direct solar radiation. To quantify the energy efficiency of a CPV module or system obviously the direct solar irradiance, called ...

DNI measurements with pyrheliometer

DNI measurements with pyrheliometer

Solar Direct Normal Irradiance (DNI) represents the direct solar component and contains about 80% of the total solar energy budget on earth. Outside the atmosphere (AM0) the solar ...

DHI Measurements

DHI Measurements

Diffuse Horizontal Irradiance measurements are performed with a thermopile sensor (Pyranometer) mounted on a Sun tracker or shadow band.  When the pyranometer is installed on ...

Solar radiation energy budget studies

Solar radiation energy budget studies

The Meteorological research community is very ambitious to understand climate changes and global impact on life. With modern advanced measurement equipment, e.g. satellites, remote ...

Universal mountings STR-21G / 22G

Universal mounting plates and side mounting are available for most commercial sensors. For specific requirements about mountings we can offer you various solutions. Please contact EKO instruments for further information or advise. 

 

Manf. Pyranometer Pyrgeometer Pyrheliometer
EKO MS-802, MS-402, MS-410 MS-202 MS-56
Kipp & Zonen CM, CMP Series CGR3, CGR4 CH1, CHP1
Eppley PSP, 848 PIR NIP, AHF
PMOD   PMO-6
  Able to mount ventilated sensors.  

 

Product dimensions STR-21G / 22G

STR-2xG_zu

 

Universal mountings STR-32G

Universal mounting plates and side mounting are available for the MS-spectroradiometer series. For specific requirements about mountings we can offer you various solutions. Please contact EKO instruments for further information or advise. 

 

  MS-Pyranometers MS-56 MS-700 MS-710 MS-712
Shading Ball assembly X - X X X
Large size top mounting plate X - X TMP-WISER
Side mounting plate / bracket X - X STR-32-S STR-32-P 

The STR-series brochure gives an overview of all available options.

Product dimensions STR-32G

Product dimension equal to STR-21G/22G except tripod.

Frequently Asked Questions

Function of the sun sensor

Function of the sun sensor

What is the function of the sun sensor on the STR-sun trackers? The sun sensor is a crucial component needed for accurate sun tracking. Since the STR sun tracker follows the sun ...

STR sun tracker used as positioner

STR sun tracker used as positioner

Can the STR sun tracker be used as positioner? The STR sun trackers can either be used for sun tracking as positioning applications. Due to the simple control command protocol ...

Soiling effect versus measured irradiance

Soiling effect versus measured irradiance

What is the effect of soling versus the measured irradiance? Measuring solar radiation with pyranometers, pyrheliometers or spectroradiometer, soiling has will have an effect ...

STR Sun Tracking Principle

STR Sun Tracking Principle

How can STR- Sun Tracker track the Sun?   From sun rise to sun set the compact EKO Sun-Trackers guarantee accurate sun tracking and pointing of the attached solar sensors. The ...