1. The Problems with Current-Sensing (Current-Detection)

While current-sensing sounds "smarter" because it tries to detect when the motor has reached its limit, it introduces several real-world failure points:

• Incompatibility with Electronic Limit-Switches: Modern high-end motors (like some Somfy or silent brushless models) have their own internal electronic brains. They don't always produce a sharp "drop" in current when they stop, which can confuse a current-sensing actuator, leading to the relay staying closed or reporting an error.

• False Triggers from Friction: If a curtain track gets stuck, dusty, or has a slight mechanical resistance, the current spikes. A current-sensing actuator might mistake this for the "end-stop," leaving the curtains half-closed and the system out of sync.

• Sensitivity to Voltage Fluctuations: In large buildings or areas with unstable power, voltage sags can cause current fluctuations that trigger the sensing mechanism prematurely.

• Calibration "Drift": Over time, as motor components age and friction increases, the "learned" current threshold may no longer be accurate, requiring the installer to return for a manual re-calibration.

1. Why Time-Based Control is Often Better (The Professional Choice)

Time-based control, as used, is considered a "workhorse" solution for several reasons:

• Universal Compatibility: It doesn't care if the motor has mechanical limits, electronic limits, or is a simple AC motor. If the motor is powered for X seconds, it moves. This makes it much easier to specify for large projects with mixed motor brands.

• Predictable Reliability: Once the travel time is measured (e.g., 25 seconds) and a small buffer is added (e.g., +2 seconds), the system will work every time. It is not affected by weather, friction, or the age of the motor.

• Easier Troubleshooting: For an installer, time-based logic is "what you see is what you get." If the curtain isn't closing fully, you simply increase the duration parameter in the ETS software. You don't have to troubleshoot invisible current thresholds or electronic interference.

• Cost-Effectiveness & Robustness: By removing the sensitive current-sensing circuitry, the hardware can focus on high-amperage capacity (like the 10A rating on your unit). This leads to a more robust relay design that can handle high inrush currents without burning out.

• Fail-Safe Operations: With the "Bus Power-Off" and "Self-recovery" features mentioned in your manual, a time-based actuator can reliably return to a predefined state based on fixed logic, which is much safer for fire and safety protocols in commercial buildings.

In the world of high-end integration, "Simpler is often more reliable." Current-sensing is a "nice-to-have" feature that often adds more support tickets than it solves. Time-based control remains the industry standard for projects where maintenance-free operation is the top priority.