Range: 0 ~ 2000ppm / 0-5000ppm accuracy: ± (40ppm + 2% f • s) resolution: 1ppm power supply mode: DC5V wiring mode: RS-485 signal: 4-wire RS-485 signal: support Modbus Protocol (baud rate 9600 can be set, address 0-255 can be set) load resistance: voltage type: RL ≥ 1K, current type: RL ≤ 250 Ω working temperature: - 40 ℃ ~ 70 ℃ relative humidity: 0 ~ 99% product power consumption: 4.8mw