TM: RS232 thermometer

Thermometer for serial port RS232
19,80 EUR 23,96 EUR incl. VAT
Personally in Prague:nowWith a delivery company:at the latest within two days
Thermometer for serial port RS232
Thermometer for serial port RS232

TM is a cheap RS232 serial thermometer with measuring range from -55 °C to +80 °C. It communicates in a simple ASCII format.

Digital sensor TM can very easily measure temperatures and transmit those measured-out values to a PC. As a transfer protocol TM uses a simple ASCII format so there is no conversion needed (Output directly in degrees celsius °C). It is connectrd to the PC via a COM port (RS232).

Features of simple serial thermometer

  • Measures temperatures from -55 °C to +80 °C, 0,1 °C resolution
  • Output is in ASCII format in °C, no conversion needed.
  • Connects to a serial port (COM)
  • Port powered
  • Wix software included (freeware)
  • Easily integrated in own applications (DLLs, souce codes and communication description provided freely)


  • Temperature meaurement for living areas, warehouses and manufacturing areas.
  • Outside temperature measuring (waterproof sensors available on request)
  • Local area information on your WEB site - internet thermometer

Sensor cable length

Standard cable length is 3m. Other lengths available on request. Maximum cabnle length is 20m


Connection of RS232 thermometer

TM Thermometer is to be connected to your PS's COM port (Serial port). Sensor is to be located in the area you need to measure.

Technics Specifications

Measurement range -55 °C to +80 °C
Accuracy ±0,5 °C in range -10 °C to +80 °C, otherwise ±2 °C
Resolution 0,1 °C
Resolution ASCII, described below
Measurement rate

First readout 1s,then 1x in 10s ±2%

Communication line RS232 (COM port; simplified)

Thermometer function description

TNM is connected and powered from a serial port (COM). Once the DTR signal is activated, TM measures temperature and sends it to the PC in ASCII format as a string. When DTR is active continuously, TM sends the current temperature every 10s. This is indicated by an LED on the RS232 connector. Standard sensor is fo atmospheric measurements only.


TM only has on serial connector (CANON9, DSub9) that is to be connected directly to a PC.

Used signals are in the table:

pin RS232 signal
2 RXD Recieves data from the sensor - measured temperature
4 DTR Powers and controls the sensor
5 GND Signal grounding

Thermometer communication protocol

TM can be easily used with a supplied software (WIX), custom software or any terminal (TeraTerm, Telix, hyperterminal). Customer made softweare is another option as the communication protocol is very simple.

(from PC to TM)
Function Output (from TM to PC)
DTR signal active Power on, measurement <sign><3 characters - 
°C><decimal point><1 character - decimals><C><Enter>
Example: +025.3C
DTR signal continuously active Periodic sending of a current temperature

TM service ... a Windows service to view TM or TMU temperatures

TMservice is a resident service for Windows OS, which can be used to view TMU or TM thermometers. It can watch set-up thresholds, store measured-out values and inform users about the sensor. More info...
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