Optical door switch

The CS211 uses an optical sensor and LED to detect door opens and closes. A combination of ambient light and reflected light measurements are used to determine the state of the door. To ensure reliable operation, install the reflective tape A material that reflects light back towards its source. It uses microscopic glass beads or prisms to redirect light, making objects highly visible, especially in low-light conditions. inside the enclosure door directly opposite the CS211 (see Mounting).

The following table describes the different Door States and values. For more information about how the CS211 determines each Door State, see Enclosure door state.

Door switch states
Door state	Value	Description
Unknown	–1	Default on power up or when door reflectivity is poor. Unable to reliably detect the current door state.
Closed	0	High reflectivity, the door is closed.
Open	1	Increased ambient light or low reflectivity means the door is open.

If the CS211 is unable to detect enough reflected light while the enclosure door is closed, the Door State is Unknown (–1), check the installation of the reflective tape and ensure there are no obstructions between the CS211 and the inside of the door.

While Door State represents the current state of the door, Door Opens (R3!) can be used to get the total number of times the door has been opened since the last measurement, reducing the number of times the sensor needs to be polled by the data logger.