RS485 Photosynthetically Active Radiation (PAR) Sensor (400-700nm)

Q: What are the possible reasons for no output or output errors?

1. The sensor is a precision device. Please do not disassemble it by yourself when using it to avoid damage to the product.<br> 2. If the reading value is 0, check whether there is a light source and whether the product protective cover is removed.<br> 3. The 485 bus is disconnected, or the A and B lines are connected in reverse. Check whether the power supply meets the marking.

1. Example Code for Arduino-Read PAR Value

This project demonstrates how to read the photosynthetically active radiation (PAR) value from the RS485 PAR Sensor (SEN0641) using an Arduino UNO R3. Users will learn to interface the sensor with an Arduino via a Gravity: Active Isolated RS485 to UART Signal Adapter Module (DFR0845) and use the Modbus-RTU protocol to retrieve the PAR value for environmental or agricultural monitoring.

Reference

This article delves into the Modbus-RTU communication protocol, explaining the data frame format, register addresses, and communication parameters essential for effective sensor data management.

Parameter	Value
Power supply voltage	DC5~30V
Working current	<10mA
Output mode	RS485
Measurement range	0~4000umol/m²•s
Wavelength range	400-700nm
Accuracy	±5% (1000umol/㎡•s, @550nm, 60%RH, 25℃)
Resolution	1 umol/m²•s
Response time	10us
Non-linearity	<±1%
Annual stability	≤±2%
Cosine response	≤±10%
Working temperature	-25°C~+60°C
Protection level	IP67
Sensor cable length	20cm
Adapter cable length	70cm

Num	Label	Description
Brown line	VCC	Power input positive pole, DC5-30V power supply
Black line	GND	Power ground wire
Yellow line	485-A	RS485 data line A
Blue line	485-B	RS485 data line B

RS485 Photosynthetically Active Radiation (PAR) Sensor (400-700nm)

Specification

Pinout