... connection 2)Display:backlight LCD, LED 3)Unit:ppm, mA, %,%LEL,%VOL 4 ... Technical features* 4-20mA, 3 wire connection ,compatible with existing alarm control unit or DCS (Distributed Control System ... superimposed communication signal for HART protocol * Failure signal: 3.6mA * T90 response time: <30 sec* Resume ... 50 bar graph display 0-100% full scale* Unit: ppm, mA, %,%LEL,%VOL* Operating temperature: ...