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STR-21G Sun Trackers

  • Single arm Sun Tracker
  • GPS for easy and accurate set up
  • Standard Integrated Sun sensor
  • Power consumption less than 10W
  • RS-232 serial interface for position control

The compact single arm sun tracker is perfectly suited to support all kinds of Global, Diffuse and Direct Radiation measurement sensors. STR-21G is the base of the Solar Monitoring Systems (STR-21G-S), a turnkey measurement solution from EKO. The STR-21G provides a fully automated set up procedure through a GPS receiver providing increased reliability and enhanced functionality.

From sunrise to sunset the compact sun-tracker guarantees accurate sun tracking and pointing of the attached solar sensors. The 2-axis tracker automatically adjusts to the sun’s position by the sun sensor closed-loop control system, even if the tracker is not oriented or leveled properly.

The sun-tracker comes standard with a small table tripod (larger tripod available). The 24 VDC low power consumption tracker can be powered by a solar-powered battery system or DC power supply. A wide range AC power adapter can be supplied to connect to the grid.

For over 20 years our clients who have deployed the STR sun-tracker, experience ease of set-up, operating and reliable tracking.

Weight 14.5 kg
Dimensions 380 × 430 × 440 cm


Pointing accuracy Solar elevation: 0 to 87°

< 0.01 °

Angle resolution

0.009 °

Rotation angle Zenith

-15 – 95 °

Rotation angle Azimuth

0 – 360 °


12 Nm

Payload side arms

7.5 kg (Total payload 15kg)

Sun sensor FOV

30 °

Ingress protection IP


Operating temperature range

-40 – 60 °C


RS-422 / 232C

Power consumption

< 10 W

Power supply

21 to 31 VDC / 15W

Power supply (Power Adapter)

100 to 240 VAC / 20W

Dimensions mm

430 (W) x 380 (L) x 440 (H)


14.5 kg (With tripod)


Stepper motor

Driving technology

Harmonic drive®

Tracking mode

Solar postion / Free positioning


Table tripod

Pyrheliometer mount

Adjustable / One position

Cable length

10 m