Taoglas RS485 Modbus Sensors (Bus Probes)

Taoglas RS485 Modbus Sensors (Bus Probes)

Courtesy of Taoglas : RS485 Modbus Sensors (Bus Probes)

Bus Probes are a family of environment sensors with an RS485 interface. The Probes communicate using standard Modbus RTU protocol.

At the moment, Tibbo offers four types of probes: ambient temperature sensor (BP#01), ambient temperature and humidity sensor (BP#02), ambient light sensor (BP#03), and 3-axis accelerometer (BP#04).

Bus Probes are typically wired to a twisted pair cable, which distributes power and carries RS485 “+” and “-” lines. All probes accept the supply voltage in the 4V to 15V range. This allows you to power them from 5V sources (for example, the 5V output of the Tibbit #00-3), as well as standard 12V power supplies. Wide supply voltage range also means that you can allow for a significant voltage drop along the bus, i.e., use a bus cable of considerable length.

BP sensors are very compact (external dimensions only 40 x 36mm) and sport an attractive look and feel. Each sensor has two mounting holes for attaching it to walls and other surfaces.

Tibbo supplies two TPS2(G2)-compatible Tibbo BASIC applications for convenient setup and testing of Bus Probes (see BP-Tester-UI and BP-Tester-Web).

Test App for Bus Probes: UI version

This Tibbo BASIC app allows you to set up and test Tibbo Bus Probes, also known as “RS485 Modbus Sensors.” Users interact with the app through the LCD and keypad of the TPS2L(G2) device (there is also a BP-Tester-Web app that implements a web interface).

Test App for Bus Probes: Web version

This app uses DHCP, so you will need to find out the IP address of your TPS box before you can point your browser at it. The easiest way to do this is by using the Device Explorer utility. You can install just the Explorer, or our Tibbo IDE (TIDE) software — Device Explorer will be installed along with it.



  • Half-duplex (two-wire) RS485 interface.
  • Communications parameters: 38400-8-N-1.
  • Modbus RTU protocol.
  • BP#01 (ambient temperature sensor):
    • Measurement range: -40 to +125°C*;
    • Measurement resolution: 0.25°C;
    • Measurement accuracy: ±1°C.
  • BP#02 (ambient temperature and humidity sensor):
    • Temperature measurement:
      • Measurement range: -25 to +50°C;
      • Measurement resolution: 0.5°C;
      • Measurement accuracy: not specified.
    • Humidity measurement:
      • Measurement range: 10 to 90%RH;
      • Measurement resolution: ±0.1%RH;
      • Measurement accuracy: ±5%RH;
      • Temp. range for valid humidity measurements: +5 to +50°C.
  • BP#03 (ambient light sensor):
    • Measurement range: 1 to 65528 lux;
    • Measurement resolution: 1 lux;
    • Measurement accuracy: 1 lux.
  • BP#04 (3-axis accelerometer):
    • Independent X, Y, and Z axes;
    • Measurement range for each axis: ±6G;
    • Measurement resolution for each axis: 0.003G;
    • Measurement accuracy for each axis: 0.1G.
  • Green and red status LEDs.
  • Power: 4 ~ 15VDC.
  • Dimensions excluding connectors (LxWxH): 40 x 36 x 19mm.
  • Operating temperature range: -40 ~ +85C.
  • Internal firmware is upgradeable through the RS485 port.

* The actual measurement range is limited by the operating temperature range of the Bus Probe itself, which is (-40 to +85°C).

See Also:

Files and Documentation

Probe Firmware bp_application_firmware_v1_10.bin
Documentation Bus Probe Manual