Description
Specifications
The full spec sheet including a programming command manual and description of the hardware, firmware, and schematic are available here (link).
| Channels | 4 |
| Voltage Input Range | 0-5V, 0-2.5V, 0-1.25V, 0-0.625V (depending on gain, default 0-5V) |
| Voltage Input Connector | 3.81mm pitch 2-pin pluggable terminal block |
| ADC Bits | 16, 14, 12 (configurable with sample rate, default 16) |
| ADC Sample Rate | 15, 60, 240 Samples Per Second (configurable, default 15) |
| ADC Gain | 1, 2, 4, 8 (configurable, default 1) |
| ADC Least-Significant-Bit Size | 176uV, 88uV, 44uV, 22uV (depending on gain, default 176uV) |
| Power – Input Voltage | 5V |
| Power – Input Source | 3.81mm pitch 2-pin pluggable terminal block OR USB-C (not both at the same time) |
| Power – Input Current | 250mA |
| Communication Interface | SCPI (through USB), RS485 |
| RS485 Connector | 3.81mm pitch 2-pin pluggable terminal block
Up to 32 boards connected to a single USB interface |
Included Parts
- 4CH Isolated ADC PCB
- 7x 3.81mm pitch 2-pin pluggable terminal block for RS485, channel inputs, and optional power input
- USB-A to USB-C cable
- Files for 3D Printed case are available on Printables here (link).
Communication
SCPI interface is available on the USB port. This device can interface with Python through PyVisa. I have created a python library for this device as well as a GUI for calibrating it automatically using another programmable multimeter and power supply.
RS485 communication interface is available (though not currently supported in the firmware). It can be used to chain up to 32 boards together with a single USB interface, allowing a total of 128 isolated voltage measurements. The first board gets powered by USB, and subsequent boards get powered by the external 5V supply. The GND of all the boards (including the one powered by USB) must be connected as the RS485 interface is not isolated.
Firmware is available on Github. You are free to modify firmware and upload your own. The simplest way is to upload over the USB interface using the Arduino IDE, but for more advanced users there are serial header pins and a BOOT0 jumper available.
