Quad Delta-Sigma Board

2016-02-22

4x AD7190 + Arduino Nano
See also The ultra low noise 24-bit ADC: AD7190

This board implements a 4 channel, ultra low noise, simultaneous sampling, 24 bit ADC. It has a dedicated oscillator and the sync line is conneted to all 4 ADCs. Its indended use is to read out 4 strain gauge weighing cells in a 6-wire configuration.

With an external reference voltage it can be used for direct voltage measurements too.

The digital part is supplied by the USB-port, and the analog part must be supplied seperately from a low noise 5V power supply (see Ultra Low Noise Linear Power Supply, using LT3042).

On each ADC only one out of two differential channels is used. See also Mehrkanal Delta-Sigma ADCs und das Abtasttheorem.

Here the blue wire was needed to supply the Arduino with 5V, because the USB-connector had an up-bent leg before soldering, and therefore the V+ pin was not connected to the Arduino-PCB. When I fixed this, I removed the blue wire.

R-Core transformer, 230V to 2x 9V. This type of transformer has the least capacitive coupling. It's good to avoid common mode currents.

Here a close up of the board:

Between the transformer and the ADC-board there is the Ultra Low Noise Linear Power Supply, using LT3042

• KiCad Project, V1.0
• Schematic, V1.0