HI Dhiren,
You can use the BCS to check if the TC is open, just don't leave it on when you take a temperature measurement as this will add error. In other words, take two separate measurements.
As far as the TC measurement itself, you must be within the correct common mode for the ADC. As long as the TC contact connection is within the correct common mode range the measurement is valid. So as I have stated in an earlier post, you need to make sure the potentials are referenced appropriately. Analog ground may not be at the same potential as the TC connection. Turning on VBIAS will establish a common potential, but there still may be issues relative to the power origination and the TC contact point causing a large potential difference. If the potential difference is large enough, high currents can run through the ADS1148 through either the ESD cells or the VBIAS if used. These high currents may damage the ADS1148. Make sure that you do not exceed the absolute maximum specifications for the ADS1148.
Best regards,
Bob B
