RS485 Modbus DS18B20 One Wire Temperature Humidity Sensor

DS18B20 temperature sensor is a kind of often used digital temperature probe, it is featured with small size, lower cost, higher accuracy, one wire communication, networking, etc. Its temperature range is -50 to 120 Deg.C. DS18B20 is released by Dallas Maxim. But users should pay much attention to a fact that imitated version or refurbished have been up in market.

One Wire Communication
DS18B20 temperature sensor can support networking by 1 wire. The wire doesn't need external power. Because each DS18B20 has an serial number, multi-piece DS18B20 can be communicated though one wire. This makes it convenient to be put at different places. DS18B20 temperature sensor can be used for process control and monitor, e.g. air conditioning environmental control, temperature sensing of inner building and machine, etc.

The DS18B20 temperature sensor with RS485 Modbus  has two kinds of structures: one is integrated type,and the other is separated type with Din-rail electronic conversion module. The following is integrated type.You can find electronic converter and DS18B20 is not installed together. This design can ensure the sensor accuracy because the released heat by electronic converter won't cause any influence to the DS18B20 probe.

RS485 Modbus with Display

• DS18B20 electronic part is not water-proof
• Steel probe is water-proof
• Power supply:5-24Vdc(Note1)
• Accuracy: +/-0.5 Deg.C.
• Total length:1.5meter.Other length can be made.

RS485 Modbus,No display

• Steel temperature probe water-proof
• Electronic conversion part not water-proof
• Power supply: 5-12Vdc.
• Accuracy: +/-(0.2-0.5) Deg.C.
• Total length: 1.5meter.

Water-proof DS18B20 to RS485 Modbus,No Display

This model is no display,but water-proof version. If your application is used in house, water-proof is not necessary. After all, once is made with water-proof, it won't be repaired or updated.

• No display
• Water-proof
• Power supply: 5Vdc(Note2)
• Accuracy:+/-0.5 Deg.C.

Note: The default is not water-proof version. If require water-proof, please indicate while order.

Note1:

• When you firstly use the model, it is better to buy our USB-RS485 converter and then download our setting software. After wiring, please test whether can read temperature value. If yes, it will mean our temperature sensors have no problem.
• The default is that electronic conversion part is not glue injection. If need it, please kindly indicate while order.
• This model supports 5-24Vdc. But when use 6-24Vdc,please don't do hot plug while on power. Before power on, please doubly check whether the wiring is connected rightly.Once make power to RS485 terminals, it will burn 485 IC, RS485 communication won't work.
• If use 5Vdc power supply, it has no such problem,because 485 IC is 5V power supply.

Note2:  The two models have no inner isolation because limited by body size. So please don't make power to RS485 while using, otherwise it will damage the temperature sensor.

Water-proof DS18B20 Temperature Sensors with Micro USB

 
Except one-wire and RS485 Modbus, many applications may require DS18B20 with USB or Micro-USB port. By USB port, computer can directly gather temperature signal from DS18B20 sensors,e.g. water temperature,etc.

One Wire Temperature Humidity Sensor

One wire temperature humidity sensor usually supports one-wire digital I2C output which features low cost and easy to use. As the meaning of one-wire, it refers to one wire can provide power supply and signal output. This can save cost of wiring connection and make it easy to operate. But it also has important disadvantages: shorter communication distance. Thus in order to solve the problem,we developed temperature and humidity sensor with one-wire RS485 Modbus output.

The default of one wire temp.humidity sensor is developed digital CMOS technology which can provide good performance with high cost-effective solution. But if you want more sensitive reaction for temperature measurement, we can provide temperature and humidity sensor with DS18B20 or PT100+high accuracy moisture-sensitive components.

Why RS485 Modbus Better Than 1 Wire?
One wire I2C communication provides many good advantages, but comparing with RS485 Modbus, it has several disadvantages, e.g. short communication distance, less weaker anti-interruption, not precision protocol like modbus, etc. Thus, if possible, we firstly recommend to use one wire temperature humidity sensor with RS485 Modbus protocol to replace I2C communication.