we offer H2s Fixed Gas Detecting Transmitter.QB2000T is a fixed gas detecting transmitter. Which provides 4-20 mA output and RS485 ModBus RTU output proportional to the gas concentration with electrochemical sensor, which is flexible, durable, swift and etc. and can be directly connected with DCS systems. It has been widely used in petrol, chemistry, metallurgy, artifice, gas transportation, biological medicine and water procession etc to test multi-gas, such as flammable gas and toxic gas O2H2SCOHCNNO2SO2NH3HCLCL2H2.Characteristics:Sensor types: electrochemical sensor4-20mA analog output(3+ channel) for direct communication to DCS system and RS485 ModBus output Sensor module design on -spot replacement s and automatically distinguish sensor fault and current display fault simultaneously.LED Display(LCD optional)Password verification for repeat operation, avoid fault operations.-40+70 following compensation for accurate detecting.Second grade visual alarms on-site and Relay(connected with audible/visual alarms or drive exhaust device).User-selectable alarm setpoint(s).