Reliable Soil Monitoring Solutions From Our Factory - Temperature & Humidity Sensor Transmitters

Technique Parameter

Measurement range	soil moisture 0 ～ 100% soil temperature -20 ~ 50 ℃
Soil wet resolution	0.1%
Temperature resolution	0.1 ℃
Soil wet accuracy	± 3%
Temperature accuracy	± 0.5 ℃
Power supply mode	DC 5V
	DC 12V
	DC 24V
	Other
Output form	Current: 4～20mA
	Voltage: 0～2.5V
	Voltage: 0～5V
	RS232
	RS485
	TTL Level: (frequency; Pulse width)
	Other
Load resistance	Voltage type: RL≥1K
Load resistance	Current type: RL≤250Ω
Working temperature	-50 ℃ ～ 80 ℃
Relative humidity	0 to 100%
Product weight	220 g probe with transmitter 570 g
Product power consumption	about 420 mW

Calculation Formula

Soil humidity: Voltage type (0 ～ 5V output): R = V / 5 × 100% (R is the soil moisture value and V is the output voltage value (V)) Current type (4 ～ 20mA output): R = (I-4) / 16 × 100% (R is the soil moisture value, I is the output current value (mA)) Soil temperature: Voltage type (0 ～ 5V output): T = V / 5 × 70-20 (T is the measured temperature value (℃), V is the output voltage value (V), this formula corresponds to the measurement range -20 ～ 50 ℃) Current type (4 ～ 20mA) T = (I-4) / 16 × 70 -20 (T is the measured temperature value (℃), I is the output current (mA), this formula corresponds to the measurement range -20 ～ 50 ℃)

Wiring Method

1. If equipped with a weather station produced by the company, directly connect the sensor to the corresponding interface on the weather station using a sensor line; 2. If the transmitter is purchased separately, the corresponding line sequence of the transmitter is:

Line color	Output signal
	Voltage	Current		communication
Red	Power +		Power +		Power +
Black（green）	Power ground		Power ground		Power ground
Yellow	Voltage signal		Current signal		A+/TX
Blue					B-/RX

Transmitter voltage and current output wiring:

Wiring for voltage output mode

Wiring for current output mode

Structure Dimensions

Sensor Size

MODBUS-RTUProtocol

1. The serial format Data bits 8 bits Stop bit 1 or 2 Check Digit None Baud rate 9600 Communication interval is at least 1000ms 2. Communication format [1] Write device address Send: 00 10 Adress CRC (5 bytes) Returns: 00 10 CRC (4 bytes) Note: 1. The address bit of the read and write address command must be 00. 2. Adress is 1 byte and the range is 0-255. Example: Send 00 10 01 BD C0 Returns 00 10 00 7C [2] Read device address Send: 00 20 CRC (4 bytes) Returns: 00 20 Adress CRC (5 bytes) Explanation: Adress is 1 byte, the range is 0-255 For example: Send 00 20 00 68 Returns 00 20 01 A9 C0 [3] Read real-time data Send: Adress 03 00 00 00 02 XX XX Note: as shown below

Code	Function definition	Note
Adress	Station number (address)
03	Function code
00 00	Initial address
00 02	Read points
XX XX	CRC Check code,front low later high

Returns: Adress 03 04 XX XX XX XX YY YY Note

Code	Function definition	Note
Adress	Station number (address)
03	Function code
04	Read unit byte
XX XX	Soil temperature data (high before, low after)	Hex
XX XX	Soil humidity data (high before, low after)	Hex
YY YY	CRCCheck code

To calculate the CRC code: 1. The preset 16-bit register is FFFF in hexadecimal (that is, all are 1). Call this register the CRC register. 2. XOR the first 8-bit data with the lower bit of the 16-bit CRC register and put the result in the CRC register. 3. Shift the contents of the register to the right by one bit (toward the low bit), fill the highest bit with 0, and check the lowest bit. 4. If the least significant bit is 0: repeat step 3 (shift again), if the least significant bit is 1: the CRC register is XORed with the polynomial A001 (1010 0000 0000 0001). 5. Repeat steps 3 and 4 until 8 times to the right, so that the entire 8-bit data has been processed. 6. Repeat steps 2 to 5 for the next 8-bit data processing. 7. The CRC register finally obtained is the CRC code. 8. When the CRC result is put into the information frame, the high and low bits are exchanged, and the low bit is first.

Instructions for use

Connect the sensor according to the instructions in the wiring method, then insert the probe pins of the sensor into the soil to measure humidity, and turn on the power and the collector switch to obtain the soil temperature and humidity at the measurement point.

Precautions

1. Please check whether the packaging is intact and check whether the product model is consistent with the selection. 2. Do not connect with power on, and then power on after checking the wiring. 3. Do not arbitrarily change the components or wires that have been soldered when the product leaves the factory. 4. The sensor is a precision device. Please do not disassemble it by yourself or touch the surface of the sensor with sharp objects or corrosive liquids in order to avoid damaging the product. 5. Please keep the verification certificate and certificate of conformity, and return it with the product when repairing.

Selection Table

No	Power supply	Output Signal	Instructions
LF-0008-			Soil temperature and humidity sensor
	5V-		5V power supply
	12V-		12V power supply
	24V-		24V power supply
	YV-		Other power
		V	0-5V
		V2	0-2.5V
		A1	4-20mA
		W1	RS232
		W2	RS485
		TL	TTL
		M	Pulse
		X	Other
E.g.: LF-0008-12V-A1:Soil temperature and humidity sensor 12V power supply, 4-20mA current signal output

Troubleshooting

1. When the output is detected, the display indicates that the value is 0 or is out of range. Check whether there is obstruction from foreign objects. The collector may not be able to obtain the information correctly due to wiring problems. Please check whether the wiring is correct and firm; 2. If it is not the above reasons, please contact the manufacturer.

Soil temperature and humidity sensor soil transmitter

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