Features: 1. High precision, up 0.5% F.S. 2. Operation without opening the housing, a high degree of protection for true local control. 3. intrinsically safe explosion-proof, safe and reliable performance. 4. Simple structure, small size, can be installed on a small actuator. 5. Automatic tuning, automatic diagnosis, the valve characteristic curve can be configured settings. 6. fewer mechanical parts, good vibration resistance. 7. situ or remotely set parameters. 8. low power, low air consumption, low running costs. 9. uses two-wire 4 ~ 20mA standard signal. 10. Built-in lightning protection module, to avoid damage due to lightning strike locator.