GF Single-Axis Solar Tracker Controller: Hard Limit and Soft Limit Protection

Single-Axis Solar Tracker Controller: Hard Limit and Soft Limit Protection

Single-axis solar tracker controllers require Hard Limits and Soft Limits to protect photovoltaic tracking structures from excessive rotation, mechanical damage, or motor overload. Below is an explanation of their functions and how they work:

1. Hard Limit: Physical Protection

Hard limits provide physical end-point protection, ensuring that the solar panels do not exceed a safe range, even in the event of controller failure.

1.1 Limit Switches

Limit switches (such as micro switches) are installed at the extreme left and right ends of the tracking path. When the tracking structure reaches these extreme positions, the limit switch is triggered, immediately cutting off the motor power and stopping the rotation. This method operates independently of the software system, ensuring safety even if the program malfunctions.

1.2 Overcurrent Protection

Advanced controllers monitor motor current, and if it reaches a predefined threshold (e.g., when obstructed by a physical object), the controller automatically stops the motor to prevent overload damage.

2. Soft Limit: Software-Based Protection

Soft limits are logic-based restrictions programmed into the controller to prevent excessive rotation beyond safe angles.

2.1 Preset Angle Range

The MCU (Microcontroller Unit) or PLC (Programmable Logic Controller) sets a maximum rotation angle (e.g., -60° to +60°). The controller continuously reads sensor data and slows down rotation when approaching the limits (e.g., at ±58°) to prevent abrupt stops or collisions.

2.2 Sensor Feedback Mechanism

• Angle Sensors (e.g., rotary encoders, gyroscopes): Continuously monitor the panel's angle, stopping the motor if it exceeds the preset range.

• Light Sensors: If light sensors detect the sun outside the expected range, the controller halts tracking to prevent errors in movement.

2.3 Remote Monitoring and Adjustment (IoT Integration)

Modern intelligent tracking controllers can monitor operational status via the cloud. If an anomaly is detected, the system can automatically adjust settings or send alert notifications.

3. Hard Limit vs. Soft Limit: Comparison and Coordination

Optimal Protection Strategy

1. First Line of Defense: Soft Limit – Angle sensors or software logic stop the motor in advance to enhance operational efficiency.

2. Second Line of Defense: Hard Limit – If software fails, hardware switches forcibly stop motion, preventing mechanical damage.

By combining soft limits for precise control and hard limits for fail-safe protection, single-axis solar tracking systems achieve both efficiency and reliability, ensuring long-term stable operation!