ADS1120EVM: ADS1120EVM

Hi Amina,

The temperature conversion can be a little confusing.  The first thing to remember is the data output from the ADS1120 is always 16 bits, but the temperature sensor itself is only 14 bits.  When considering the temperature sensor data you always start from left and consider those bits even if they are 0.  In ADCPro you would use the Data Monitor plugin to view the data, but then you have to manually calculate the data to get the temperature.

Let's say I see the hex value of 0x0C65 in the data monitor window.  At first glance this may appear to be only a 12 bit value, but you must also consider that a '0' is also valid.  The same value in binary would be 0000 1100 0110 0101.  Starting at the left, we only consider the first 14 bits which are 00 0011 0001 1001.  In hex this now becomes 0x319. 

Computationally another way to look at this is to right shift the data by two (>>2).  0xC65 >>2 = 0x319.  The decimal value for 0x319 is 793 decimal.  The temperature degree per count from the datasheet is 0.03125 deg C. 793 * 0.03125 = 24.78 deg C at the time I collected the data.

If you look at Table 12 on page 31 of the ADS1120 datasheet you will see that 0x319 is very close to the value for room temperature.

Best regards,

Bob B