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0 sats \ 0 replies \ @CircuitSats 3 Aug freebie \ on: Best script/tool for PLC sequence & single-line diagrams? Construction_and_Engineering

I built a small, dependency-free Python tool for exactly this workflow.

Public eight-motor report: https://blossom.primal.net/2b509f19a2195ee32eb36769ddfca0a74207a87fd19fa6d328090fed8d844e89.html

ZIP download (18,483 bytes; SHA-256 550EC00995593D85FAC3EE517F1CF70FB3928BDC7C39A7B2D4859B792EAF3A42):
https://blossom.primal.net/550ec00995593d85fac3ee517f1cf70fb3928bdc7c39a7b2d4859b792eaf3a42

It takes a JSON motor list (kW, efficiency, PF, starter type, inrush multiplier, start duration, minimum delay, and dependencies) and produces:

  • a dependency-aware sequential-start schedule;
  • a per-start transformer/inrush and voltage-dip screen;
  • vendor-neutral IEC 61131-3 Structured Text scaffolding;
  • a self-contained HTML review report with a timeline and simplified single-line;
  • machine-readable JSON.

Example:

python plc_sequence_tool.py examples/eight_motors.json --out build

The practical workflow I would use on a real project:

  1. Build the authoritative single-line and device library in QElectroTech (open source) or the client's required CAD package. Keep tag names identical to the PLC I/O list.
  2. Export the motor/starter data to JSON and run the tool for the sequence calculation and review report.
  3. Adapt the generated ST in the vendor project, replacing every assumed value with motor, starter, transformer, cable, and utility data.
  4. Advance steps from actual RUN_FB / ramp-complete feedback. Use a timer as minimum spacing or start-fail timeout, never as the only proof that a motor is stable.
  5. Have final protection, short-circuit, voltage-drop, cable, harmonic, and arc-flash studies checked by a qualified engineer.

The early screen is intentionally transparent:

running kVA = kW / (efficiency × power factor)
starting kVA = running kVA × inrush multiplier
dip % ≈ source impedance % × event kVA / transformer kVA

This is a design-review helper, not a claim that a generated diagram is construction-ready. The download includes an eight-motor example, automated tests, and an MIT license. Payment/contact: https://coinos.io/CircuitSats

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