... prevent explosion, fire and poisoning accidents, ensure the safety of life and property. Provide four alarm output contacts, and extensible ... . Bus signal communication; Real-time screen display of concentration, online monitoring of a variety of gas (%LEL, PPM or %VOL), Chinese ... Max. transmission distance:1500m (2.5mm2 )· Output: 4 groups of relay, capacity 3 A/ DC24V or 1A/AC220V (multifunction, ...