Installing a safety light curtain at the entrance and exit of the logistics conveyor line can detect people or objects entering dangerous areas. Once someone enters, the system will immediately stop the operation of the machine to prevent accidents. However, in some situations where conveying materials or feeding intelligent cars frequently enter and exit, the system frequent operation caused by material and cars will greatly reduce production efficiency. In this case, we can use the muting (also known as "shielding") function to temporarily automatically stop the safety function of the safety light curtain during the passage of objects, while still being able to reliably detect when personnel pass through, achieving "separation of people and vehicles"

The shielding of the light curtain needs to meet specific operating conditions. When the conditions are met, the OSSD output of the light curtain always remains in the "ON" state; Once the specific operating conditions are completed, the function of the light curtain will be reset.

Implementing the shielding function safely requires both hardware and software aspects. Among them, hardware includes shielding sensors, shielding light curtain and safety controllers, Software includes sequential detection and shielding .,etc

Sequential detection: The sequence in which the shielded sensor is triggered by the workpiece is regular. Once the triggering sequence of the shielding sensor conflicts with the setting, the shielding function will be immediately interrupted.

Time monitoring: The duration of the shielding should not be too long. The maximum shielding time is generally set to the time required for the entire work piece to pass through the light curtain.

Sync Restrictions: The synchronization time between paired shielded sensors is relatively short. Limiting synchronization time can improve shielding reliability.

Override fault: In a fault state, it is necessary to temporarily override the light curtain. When a malfunction occurs, this function allows for manual removal of the work piece from the light curtain protection area.

In addition, safety shielding can be selected from the following three modes based on different working conditions, material characteristics, transmission direction, and other factors.

Sequential muting: Using a total of 4 sensors from MS1 to MS4, locate them in sequence. When the work piece enters the hazardous area, it is strictly triggered and released in sequence 1-4. When MS2 is triggered, the shielding function is activated; After releasing MS3, the blocking function is turned off, and vice versa.

Parallel muting: Use a total of 4 sensors from MS1 to MS4, paired in parallel for localization. When the work piece enters the hazardous area, it is triggered and released in the order of "1/2~3/4". When triggering the (MS1/MS2) combination, the shielding function is activated; After releasing the (MS3/MS4) combination, the shielding function is turned off, and vice versa.

Cross muting:Use a total of 2 opposing switches for cross positioning. When the work piece enters the hazardous area, MS1 and MS2 are triggered simultaneously by the work piece, and the shielding function is activated; Either MS1/MS2 is released and the shielding function is turned off.