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mkz-nv-meter

Concept for a handy Nanovoltmeter, 7.5 Digits

based on the AD7190, 24-Bit delta sigma ADC

Features

  • Graphic LCD
  • Bargraph
  • DC/AC measurements with 0.1, 1 or 10 Updates per second
  • Autorange:
    • Gain=1: ±4.096V
    • Gain=8: ±512mV
    • Gain=16: ±256mV
    • Gain=32: ±128mV
    • Gain=64: ±64mV
    • Gain=128: ±32mV
  • Manual range with dedicated range-button
  • zero-offset
  • ratiometric measurements for strain gauges
  • Min/Max/Average
  • Integration over time (for Coulomb counting)
  • Current sensing with possibility to specify a shunt resistance.
  • BNC and 4mm banana socket
  • battery powered
  • USB charging
  • USB interface, optically coupled

Components

ADC

  • AD7190
  • 24 bit
  • delta sigma
  • differential inputs
  • external 1-5V reference

Reference

  • LTC6655
  • hermetically sealed LS8 package
  • ±250ppm initial accuracy
  • ±0.25ppm peak-peak noise (0.1-10Hz)
  • 2ppm/°C temperature drift
  • 4.096V
  • optionally oven controlled @ 45°C
  • dead bug mounting (–> more long term stability)

LCD

  • ILI9341
  • 2.2 inch
  • SPI
  • 240×320
  • Backlight
  • Colour

Buttons

  • Hold
  • AC/DC
  • Speed (0.1, 1, 10 S/s)
  • Range
  • Zero
  • Min/Max (implies Average and Integral)
  • Voltage/Current
  • Cancel
  • 2nd
    • Up
    • Down
    • Left
    • Right
    • OK
    • Shunt
mkz-nv-meter.txt · Zuletzt geändert: 2017/04/04 06:45 von karl