The ZD 21 is an “intelligent” transmitter. The comprehensive electronics allow for easy operation and maintenance and also increase operational safety and accuracy. In less than 2 seconds the ZD 21 responds to an oxygen deficiency. This extremely quick response time allows the time to take measures to prevent considerable damage.

• Extremely stable sensor responds quickly to any change in oxygen (O₂) concentration
• Sensor is unaffected by exposure to high concentrations of carbon dioxide (CO₂)
• 5 year oxygen (O₂) sensor life (typical)
• Fast recovery from barametric pressure, humidity or temperature
• Minimal signal loss over time reduces the need for frequent calibration

The ZD 21 is a powerful transmitter for the detection of oxygen, using an amperometric sensor based on an electrochemical zirconium dioxide oxygen pump cell. The detection principle features good longterm stability and selectivity.

A particularly long sensor life makes the ZD 21 a low cost transmitter for oxygen monitoring. The expected lifetime of the sensor is 5 years in continuous operation. A robust aluminum casing protects the sensor and the circuitry from impacts, splashed water, and dirt.