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temp sensor

Carl Claughton-Wallin
Prodigy 10 points
Other Parts Discussed in Thread: TMP006, TMP112

We are looking for specific sensors but are however not sure of the specifications of the TI sensors and if they would suit our requirements. Here is what we are looking for:

Temperature measurement
Application:    Measure surface temperature, either by contacting the surface or by f.ex. IR measurement.
Measurement type:     Relative measurement
Response time:     Less than 1 second. Preferably around 1 degree Celsius per 0.1 seconds or better. 
Accuracy/Resolution:     Preferably at 0.0001 degree Celsius in the temperature range between +30 to +40 degrees Celsius.
Sensor operating temp:     +0 to +60 degrees Celsius
Storage temp:     Optimum -40 to +120 degrees Celsius. Minimum 0 to +85 degrees Celsius. 
Signal:     Preferably Analogue but digital may be ok
Voltage:     Maximum 5V. Other voltage may be possible but preferably not.

We really appreciate a fast answer of what type could suite our needs!

Thanks and best regards,

Carl

  • 0
    TI__Expert 6930 points

    Hi Carl,

    Thank you for inquiring about TI's temperature sensors...let me provide a few points of information here to help you narrow your choices...

    With regards to your application to measure a surface temperature you can use a local temperature sensor, a remote junction temperature sensor, an IR temperature sensor or an RTD...the decision to choose one over the other may be somewhat determined by the physical environment of your application, the ability for signal processing etc.  For example if you were to select a local temperature sensor the device (and pcb) would have to be mounted in thermal contact to the surface in question.  For the IR sensor (TMP006) the surface should have high emissivity (i.e. not shiny) and you will need the ability to process the output signal which is a voltage into the temperature reading.  A one-time system (in your lab) calibration would also be required to calibrate the IR sensor to determine the coefficients required to perform the signal processing. An RTD can be easily attached using a thermally conductive epoxy to most surfaces.

    The time constant of the measurement can be a function of both the thermal mass of the system and the temp sensor itself...when considering the thermal mass of the system, minimizing the thermal mass of the temp sensor and it's PCB such that the heat transfer from the surface in question to the sensor will be a consideration.  TI's digital output temperature sensors, such as TMP112, can be programmed for as many as 8 conversions / second...reducing the number of conversions / second will produce a less noisy result if that is a consideration in your application.  The resolution of TMP112 is 0.0625C which is typical of a digital temperature sensor.  TI's temp sensors are commonly specified from -40C to 125C.  TI's portfolio of digital output temperature sensors all use the I2C or SM Bus interface.  We also have a devcie that uses a proprietery one wire interface that can be used in noisy environements when the temp sensor is located some distance from the microprocessor.  TI also has a large portfolio of analog output temperature sensors and temperature switches.

    To achieve a very high resolution I suspect you may consider the RTD + high resolution data converter approach.