• RS485 Modbus-RTU communication for direct digital value output
  • Low cost ownership
  • Suitable for RTD PT100,PT1000 and 8 kinds of TC 
  • 16bits A/D converting to ensure good accuracy
  • Sampling speed is 20times per second
  • Higher accuracy and more stable
  • TVS diode for PT100 and RS485 wiring ports
  • Baud rate and address can be set by software
  • Correction function to temperature shifting

RS485 modbus temperature humidity sensor is developed from actual requirement because many clients mention that analog 4-20mA temperature senor is the main existing model in the market. But if want RS485 Modbus, it will have to use a signal converting device. This will improve the project cost and meanwhile it reduces system stability. Thus, in order to meet the requirement, we release the series RS485 Modbus-RTU temperature transmitter with high cost-effective solution. You won't need a converting device, our temperature transmitters will directly gather physical value to digital value output.

We have RS485 temperature transmitter for PT100,8 types of thermocouples and DS18B20 and temperature humidity SHT sensors. All of them have been widely used in various of industries,e.g HAVC, building automation, various of industry manufacturing, ambient temperature humidity,etc. The RS485 Modbus-rtu is a kind of standard protocol and easily communicated with your PLC, computer and other secondary communication devices.

Why RS485 Modbus is better than Analog 4-20mA?

Analog signal mainly have current signal and voltage signal. Current signal has  4-20mA,0-20mA,and voltage includes 0-5Vdc and 0-10Vdc. Current signal is more stable than voltage signal, so 4-20mA is the main type.

Digital signal mainly include RS232,RS422 and RS485. RS232 has a short communication distance. RS422 is not the main selling. So RS485 is selected as hardware channel for Modbus protocol. Modbus protocol is a kind of very popular communication protocol. It features standard and open, simple,easy to operate, etc.

The following will do simple comparison between RS485 Modbus and 4-20mA.

  • Higher Accuracy: 4-20mA,etc belongs to analog signal,it requires signal converting. RS485 is direct digital value. Thus, RS485 has better accuracy.
  • Precision Requirement: PT100/PT1000,etc belongs to high accuracy class temperature sensors. If users select the sensors, that means projects have higher requirement for accuracy. So it is better to use RS485 Modbus.
  • Communication Requirement: RS485 Modbus can provide exact and detailed information,but analog can't.
  • Network Making: As development of internet of things and other automation, it has more and more requirement for network making. By this network, users can read related data and do monitoring in controlling center. This provides convenience and can save much labor cost.
  • Longer Communication Distance: RS485 has longer distance,but 4-20mA is short.
  • Stronger Anti-interruption: Comparing with 4-20mA, RS485 has stronger capability in signal anti-interruption.

RS485 Modbus RTU for PT100

  • Cost-effective solution
  • Accuracy:0.1%-0.2%FS
  • Signal Input: PT100;PT1000;
  • Signal output: Standard RS485 Modbus-RTU
  • Power supply: 8-30Vdc;5Vdc optional
  • Temp.Resolution:+/-0.1 Deg.C.
  • Temp.measuring range:-166 to 600 Deg.C.
  • Working temp. -30 to 70 Deg.C.

RS485 Modbus-Thermocouple

  • Accuracy:+/-0.1 Deg.C.
  • Signal Input: one way for TC K,B,S,T,N,J,R,E
  • Signal output: Standard RS485 Modbus-RTU
  • Power supply: 8-30Vdc;12V recommended. 24V need a 100ohm resistor.
  • Baud rate range:300-115200bps optional.
  • Temp.measuring range:Decided by TC type.
  • Working temp. -30 to 70 Deg.C.