SOIL HUMIDITY SENSOR

MP-508B

MANUAL

INTRODUCTION & PRINCIPLE

MP-508B sensor can be widely used in soil moisture monitoring, water-saving irrigation, greenhouse control, precision agriculture, road monitoring, hydrometeorology and other fields. It is a soil volume moisture measuring instrument developed by FDR principle. The equipment can be directly used with control instruments, and can also be connected with various data collectors, handheld terminals, etc. For scientific research or irrigation management, mp-508B probe can quickly measure soil moisture by inserting the stainless steel probe into the soil surface or soil profile. 508B water probe can be permanently buried in the ground and connected to a data recorder for long-term measurement.

Frequency domain reflectometry (FDR) is a method to measure the soil moisture content by measuring the frequency change caused by the change of the dielectric constant of the sensor in the soil, which is transformed into the voltage or current relationship corresponding to the soil moisture content. It has the characteristics of high accuracy, fast, accurate, continuous fixed-point measurement, no radioactivity and no disturbance to soil.

TECHNICAL SPECIFICATION

◆Principle：FDR

◆Structure: 4-pin

◆Measuring range：0~100%（（m3/m3））

◆Response time：＜1s

◆Accuracy：±2%（0～50%（m3/m3），25℃）

◆Measurement area：90% of the influence is in the cylinder with diameter of 2.5cm and

◆Length of 6cm around the central probe

◆Sealing material：ABS（ abrasive tools）

◆Size：133*40mm（probe：60mm）

◆Standard line length：3m

◆Stabilization time：About 10s after power on

◆Farthest lead wire：current200 m、RS485 100m

◆Ingress Protection：IP65

WIRING METHOD

RS485 output sensor is equipped with 2.5m 4-core cable as standard. Users can customize the cable with appropriate length as required. The cable specification is 0.2mm² 4-core shielded cable, and the wiring color is defined as below:

RS485
Red	Positive pole
Black	Negative pole
Green	A
Blue	B

Current output sensor is equipped with 2.5m 4-core cable as standard. Users can customize the cable with appropriate length as required. The cable specification is 0.2mm² 4-core shielded cable, and the wiring color is defined as below: