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Low-power consumption RS485 temperature and humidity probe

-40…+120°C temperature and humidity probe

  • Ultra-low power consumption, Min 3.3V…24V power supply, average working current 0.9mA
  • High accuracy for temperature ±0.3℃ and humidity ±3%RH. Higher accuracy available.
  • Power supply protection against wrong wiring connection, anti-static and surge protection

The temperature humidity sensor has a very small size and adopted with sintered copper protective shell or PE water-proof protective shell, which has air permeability, high temperature resistance and resistance to corrosion materials. The sensors are more stable and accurate, which is suitable for outdoor rain and high humidity agricultural greenhouse, etc.

Technical specification

Wiring of the temperature probe
Red Power + 3.3…24V
Black Power -
Green RS485- (B)
Yellow RS485+ (A)
Baud rate: 9600 as default
Data bit: 8
Stop bit: 1
Parity None
Modbus ID address: 1-255, default is 1
Protocol Modbus RTU
Function code: 03 (Read), 06 (Write)
Power supply: 3.3..24VDC
Temperature meassuring range: -40..+120°C
Humidity meassuring range: 0-100% RH
Temperature accuracy: 0.3°C
Humidity accuracy: 3% RH
Measurement resolution: 0.1°C, 0.1%RH
Working current: 0.9mA
Sleeping current: 18uA*
Power protection: Anti-reverse connection, ± 15kV ESD surge protection
Refresh interval: >=20ms
Baud rate: 1200,2400,4800,9600,11400,19200
Cable length: 1 meter
No communication, power on 1 flash each 4 seconds
Communicating 2 flashes within one second

Working modes

The temperature-humidity sensor is ultra-low power consumption and has 2 kinds of working modes as below:

1. Standby-Working Mode:
After power ON, the sensor goes into standby-working mode. Under such mode, the sensor receives command from master and response accordingly with related data. Communication indication light flickers normally, after each inquiry of temperature and humidity,the sensor will refresh value of temperature & humidity once.

2. Sleep-working mode:
After receiving sleeping command, the sensor will close indicate light and stop receiving data from RS485 wire, under such time, the system will be under sleeping status of ultra-low power consumption. If there is no connection of pull-up/pull-down resistor inside of the sensor, the static current is smaller than 5ua. If connected with a pull-up/pull-down resistor inside of the sensor, the static current is 50ua.

When sleep time is over or power is reseted, the sensor will automatically go to standby working mode. We suggest to send sleeping command to put the sensor into sleeping mode after each inquiry of temperature and humidity value, meanwhile, prolong reading interval of temperature and humidity value as long as possible.

public/products/rs485_temp.txt · Last modified: 2020/10/12 20:12 by Acrios Admin