If the SMTAS08 board is equipped with the TO18 version of the SMT160 sensor, then an absolute accuracy of 0.7 °C is obtained. The resolution however is 0.02 °C !
The complete specification of the temperature sensor range is presented in the datasheet, which should be consulted in conjunction with the SMTAS08 manual. (You can download both at the SupportShop)
The SMTAS08 is equipped with a Microchip PIC16F876 microcontroller. An RS232 interface chip offers external serial communication with the microcontroller. In turn each of the sensors is powered by a corresponding processor output. An analog multiplexer (74HC4051), which is controlled by the microcontroller, selects one of the eight sensor outputs by connecting it to the microcontroller input port. The input is then sampled to measure the dutycycle for this sensor (represented by two counter values, t1 and t2). This process is repeated for each of the sensors, after which the 8 values of t1 and t2 are sent to the RS232 port.
For controlling and reading the SMTAS08 board, a Labview program is available (see picture underneath) as well as a Visual Basic program. Both can be downloaded from the Supportshop. The PIC processor assembly program listing can also be found
there.
