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hardware_spec.md

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machinon Hardware Specification

Mechanical

Power

  • Supply: 10-28 V DC input (typ. 12 V or 24 V)
    • Typical consumption 200-500 mA at 12 V with Raspberry Pi 3B
  • 2 Aux 24 V outputs (max 1 A total) for powering digital inputs, relays etc.
  • 1 Aux 5 V output (max 100 mA) for small analogue sensors

Digital Inputs

  • 16 digital inputs, reported as either:
    • Logical state ON/OFF
      • Current state reported at each transition
      • Minimum 100 ms between transitions
    • Cumulative pulse count
      • 32 bit counters
      • Minimum 50 ms pulse width (max 10 Hz input frequency)
      • Optional scale and offset parameters allow output values to be presented as meter kWh or similar.
      • Counters are non-volatile (saved if power fails and restored on powerup)
      • Reported at the global update interval
  • Opto-isolated, max 300V between input COM and power supply GND
  • Input Voltage Levels
    • Active/ON: 5-24 V between input and common (max 10 mA at 24V input)
    • Inactive/OFF: 0-1.5 V between input and common
  • Each common terminal can be high or low side (NPN or PNP type input)
  • One common terminal per 4 inputs (1-4, 5-8, 9-12, 13-16)
  • Front panel status indicator LED for each channel

Analogue Inputs

  • 8 analogue inputs with software selectable input range/type:
    • 0-20 mA or 4-20 mA (200 ohm load resistance, 24 mA overload max)
    • 0-10 V (1.2 M ohm input resistance, 12 V overload max)
  • 0.1 % typical accuracy, 14 bit ADC
  • Optional scale/span and offset parameters allow data to be scaled to match sensor (eg 4-20 mA transmitter signal reported as -10…+110 degrees C)
  • Sampled at 1 Hz and reported as mean average level over each reporting interval

Current Transformer Inputs

  • 6 inputs for 333 mV type CTs
  • Optional scale parameter allows data to be scaled to match sensor (eg 0-100 A)
  • Current sampled at 1 Hz and reported as average over each reporting interval
  • Frequency of CT4 input sampled at 1 Hz and reported as average over each reporting interval

Digital Outputs

  • 16 open-drain (low side) digital outputs, switching to common ground.
  • Max 24 V in OFF state (with inductive load clamp at 50 V, but external clamp diode/snubber recommended)
  • Max 500 mA per channel in ON state, with overcurrent and thermal protection
  • Suitable for driving small relays/contactors, indicators, actuators.
  • Front panel status indicator LED for each channel
  • Outputs can be configured to start ON at powerup, or stay OFF until driven on.

RS-485 Port

  • 2-wire, half-duplex RS485 port
  • 3.3 V signal level, 5 V tolerant, non-isolated
  • Interfaces to 40-way GPIO header SPI bus via SC16IS752 UART bridge.

Status Display LCD / LEDs

  • LED indicator for each digital I/O channel
  • Status LEDs (programmable) for system status and processor/disk activity
  • LCD text display for user status info

Processor Module

  • Raspberry Pi 2 or 3 (or equivalent) single-board computer with
    • 1 Ethernet LAN port
    • Optional Wireless LAN
    • 4 USB2 ports for expansion I/O or storage
    • Linux operating system running automation software stack with secure remote access to web GUI for configuration, remote control, data reporting etc.
  • Connection to Machinon board via standard Raspberry Pi 40-way GPIO header and ribbon cable.

Miscellaneous

  • Real-time clock with battery backup
  • Unique serial number / MAC pre-programmed into board
  • Global data report interval configurable between 10 secs and 1 day