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The EVAL-CN0391-ARDZ shield is a single supply, multi channel thermocouple temperature meter. The CN0391 uses AD7124-8 8-Channel, Low Noise, Low Power, 24-Bit, Sigma-Delta ADC with PGA and Reference as integrated solution for multi channel thermocouple temperature measurement with RTD cold junction compensation.
Each of the four(4) channels uses an Omega style connector for the thermocouples, which makes it easier to plug in and out different thermocouple types. Type U was selected so that all the channels on the board (P1 - P4) would be universal and interchangeable.
There is an RTD beneath the copper tabs of each connector which is used to measure the cold junction temperature. So no external cold junction measurement is needed with this board.
The chip select header (JP1) is used to select the chip select pin on the AD7124. This allows for flexibility on the SPI bus when stacking multiple Arduino shields together. To change the chip select of the AD7124, all you need to do is move the shunt to one of the below locations, and then make the corresponding change in software.
|Jumper Position (JP1)||AD7124 Chip Select Pin (P8)|
|Across Pin 1 and 2||Pin 3|
|Across Pin 3 and 4||Pin 2|
|Across Pin 5 and 6||Pin 1|
To use the EVAL-CN0391-ARDZ with the software we provide, please connect the thermocouples to each channel and set the software to corresponding thermocouple type/channel . Please set the default jumper position as pictured:
The AD7124 Analog to Digital converter, measures each sensor input channel on the board. The results are then sent over to the processor via the SPI communications protocol. More reading about SPI Communications can be found here.
The SPI digital communications lines can be found on two(2) connectors on the EVAL-CN0391-ARDZ. P8 and P7 have the SPI lines to handle the communication between the AD7124 and the processor.
|P8 Connector Pins||SPI Function|
|Pin 1,2, or 3||SPI_CS|
|P7 Connector Pins||SPI Function|