... /mpreparation electricity working time >2 hoursconcentration of alarm 25%LEL 50%LELconcentration of alarm error < ±3%LELalarm method sound and ... light alarm, liquid crystalStructural Dimension 520mmX360mmX100mmperform standard GB16808-1997 MPU ... real-time check of data,fault detecting,power management,alarm display,alarm indication ,relay outputs etc ,1 signal for RS- ...