Hi Divya,
In response:
- I should have mentioned, that AD7193 includes a precision PGA (gain of 1 to 128). This PGA provides a high impedance input for the thermocouple, as well as gaining up the thermocouple signals to utilise more of the ADC range.
- The ±10V signals are passed through the ADG1414 switch and are deferentially buffered by the AD8676 to provide a high input impedance. The ADG1414 and AD8676 have ±15V supplies to allow for the ±10V at their inputs. The output of the AD8676 is fed into the AD8275, which performs the level shifting and attenuation (Gain = 0.2) to the range of the ADC.
- No, the RTD input would also be connected directly to the AD7193 via the ADG442. The AD8617 provides the excitation current.
- This really Depedns on your requirements:
- You can purchase the CN0209 hardware and an SDP board. The SDP board is a controller board with interface to the PC, it contains a DSP on board. www.analog.com/sdpb
- Another option is to use the ADuCM361, this is a cortex M3 core with precision 24-bit sigma delta, Mux and PGA. So this would replace the AD7193, and includes the microcontroller. Note that this is a 3.3V devices so the circuit would need to be altered accordingly.
- Alternately any other micro-controller of your choice. The AD7193 has an SPI compatible interface.
Regards,
Derrick