TTJ Temperature sensor

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TTJ Temperature sensor

One of the implemented features for fleet management devices is a 1-Wire data protocol, which enables the connection of temperature sensors. It is a perfect accessory for temperature monitoring.


  1. Thermostatic controls – maintain temperature near a desired set point.
  2. Thermally sensitive system – receive alerts when temperature enters or leaves pre-defined value.
  3. Consumer products – be assured that the goods which you are delivering will maintain high quality.

The TTJ Temperature sensor provides 9-bit Celsius temperature measurements and has an alarm function with nonvolatile user-programmable upper and lower trigger points. The TTJ communicates over a 1-Wire bus that by definition requires only one data line (and ground) for communication with a central microprocessor. It has an operating temperature range of –55°C to +125°C and is accurate to ±0,5°C over the range of –10°C to +85°C. In addition, the TTJ can derive power directly from the data line (“parasite power”), eliminating the need for an external power supply. Each TTJ has a unique 64-bit serial code, which allows multiple TTJ sensors to function on the same 1-Wire bus. Thus, it is simple to use one microprocessor to control many TTJs distributed over a large area. Applications that can benefit from this feature include HVAC environmental controls, temperature monitoring systems inside buildings, equipment, or machinery, and process monitoring and control systems.

TTJ technical characteristics

  • Unique 1-Wire® Interface Requires Only One Port Pin for Communication.
  • Each Device has a Unique 64-Bit Serial Code Stored in an On-Board ROM.
  • Multidrop Capability Simplifies Distributed Temperature Sensing Applications.
  • Requires No External Components.
  • Can Be Powered From Data Line. Power Supply Range is 3.0 V to 5.5 V.
  • Measures Temperatures from -55° C to +125° C (-67° F to +257° F) ±0.5° C Accuracy from -10° C to +85° C.
  • 9-Bit Thermometer Resolution.
  • Converts Temperature in 750 ms (max).
  • User-Definable Nonvolatile (NV) alarm settings.
  • Alarm Search Command Identifies and Addresses Devices Whose Temperature is Outside Programmed Limits (Temperature Alarm Condition).
  • Applications Include Thermostatic Controls, Industrial Systems, Consumer Products, Thermometers, or Any Thermally Sensitive System.
  • Recommendations for cabling: max. cable length 15 meters, category – CAT5. Length over 20 meters increases measuring precision error.

TTJ sensor pin-out and connection diagrams:
TTJ connection scheme.PNG Sch fmb120 ds1820.png

On the FMB unit, TTJ sensor parameters are configured as I/O element parameters: Dallas temperature and Dallas temperature ID.


The configuration procedure is as other I/O element (for example: FMB120_I/O_settings)

External links