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Agreements / Decisions

Intended for use as:

  • Shared workspace size to collaborate for system integration
  • documentation for inter-team agreements

ECAD

As the used ECAD Tooling the following options are investigated and KiCAD 8 is decided to be used as the ECAD tool for obat. Mainly because it is more suitable for the future as it is a thriving open source project and not discontinued as EAGLE. Also by its FOSS nature and the ecosystem "data ownership" is placed at obat project and not a third party company. With EAGLE being discontinued officially by 7th of June 2026 it is not seen as a future safe option for a new project.

  1. AUTODESK Eagle
    • Disadvantages:
      • discontinued (announced by Autodesk to be discontinued by 7th June 2026)
      • little to no updates
      • Not free, license required (educational license available)
      • proprietary software (Autodesk might enforce online storage)
      • licensing might change at any time
      • footprints and symbols are "linked" atomically in library (depending on opinion this can be good)
    • Advantages:
      • used at by others at HFU
      • good library support
      • nice part search bulk editing for big projects
  2. KiCAD 8
    • Disadvantes:
      • Currently not used by many other at HFU
    • Advantages:
      • Free (no license) and free as in freedom
      • Open Source
      • Active Project, Regular Updates and new versions
      • good library support
      • Footprint and Schematic symbols separated in libraries
      • EAGLE project importer
      • (softpoint) handy tools and calculators, it just works

Meeting Agreements

18. Apr 2024

  1. PC / Controller
    • separation of realtime / non-realtime code into distinct packages, which have a defined interface. This separation shall allow a change of the realtime code for harder realtime constraints. (Port of language, port to other hardware).
  2. PowerSupplySink
    • PI(D) controller for constant current or other controller type is suited better?
  3. Enclosure
    • Temperature control loop should be managed in the PC / Controller
    • Interface definition of actuators and sensors is required to be shared / agreed
    • Power for temperature control can be sourced from 24V power source by using isolation DC/DC amplifiers for other voltages.
    • safety disconnect can be achieved by using a control signal (Steuersignal) to switch a relay.

27. Mar 2024

  1. No switch/sensor at mechnical enclosure to check if enclosure is open or closed, which has to be read by other components.
    • Safety can be ensured using a concept similar to a "unloosable screw" (ger. unverlierbare Schraube)
  2. Connections from Measurement and PowerSupplySink into enclosure
    • Connected and disconnected mechanically by opening and closing the enclosure
    • Connections for 4 Wire sensing:
    • + and - connections with high current capability for power delivery
    • + and - connections in parallel with normal current capability
  3. Heating and Cooling
    • Power for heating cooling is considered part of the enclosure. Other components must only provide "information" for heating and cooling.
  4. Temperature sensing
    • [0V 5V] interface with linear mapping to temperature interval [T_min T_max]
  5. Stop Button
    • ESU has connect and disconnect button for "normal" operation
    • Before ESU is a stop button/lever disconnecting the ESU + DUT
    • Cooling, Heating & Ventilation is not stopped by the stop button
    • Color, size and type of button/lever must be investigated to be in accordance with regulations. (CE Examination)