EPLAN Electrical Symbol Recognition β€” Qwen3.5-9B Vision LoRA

Vision LoRA adapter on Qwen/Qwen3.5-9B that looks at an EPLAN / IEC / NFPA electrical schematic symbol and describes it: shape, structure, type of contact/function, and EPLAN symbol naming. Trained on 24k real EPLAN symbol images β€” part of the open EPLAN AI toolchain by Covaga Β· github.com/covagashi.

Base model License LoRA Dataset Website GitHub

πŸš€ Quickstart

# pip install "transformers>=5" unsloth peft pillow
from unsloth import FastVisionModel
from peft import PeftModel
from PIL import Image

model, processor = FastVisionModel.from_pretrained(
    "Qwen/Qwen3.5-9B", load_in_4bit=False, load_in_16bit=True,
    max_seq_length=2048)
model = PeftModel.from_pretrained(model, "covaga/eplan-2027-lora-vision")
FastVisionModel.for_inference(model)

img = Image.open("symbol.png").convert("RGB")
msgs = [{"role": "user", "content": [
    {"type": "image", "image": img},
    {"type": "text",
     "text": "Identify this EPLAN electrical symbol and describe its shape."}]}]
inputs = processor.apply_chat_template(
    msgs, tokenize=True, return_dict=True,
    return_tensors="pt", add_generation_prompt=True).to(model.device)
out = model.generate(**inputs, max_new_tokens=300)
print(processor.decode(out[0][inputs["input_ids"].shape[1]:],
                       skip_special_tokens=True))

Requires transformers>=5. Needs β‰₯24 GB VRAM for BF16 (or quantize / use the merged GGUF ecosystem below).

🧠 What it does

  • Sees an EPLAN symbol image (blue schematic glyphs, ~400Γ—400)
  • Describes its visual form accurately: lines, contacts, circles, diagonals, connection points β€” verified qualitatively on held-out symbols
  • Identifies symbol type (fuse, pushbutton, terminal, transformer…) and attempts the EPLAN short_name + variant

Verified results (24 unseen test symbols)

Aspect Result
Shape/structure description βœ… Accurate β€” correct primitives, layout, connection points
Symbol short_name recall ⚠️ 1/24 β€” arbitrary ID memorization is hard; use visual RAG for naming (below)

Example of what it produces β€” given a mushroom pushbutton symbol:

"A vertical line segment. A right-pointing triangle attached to the right side… a horizontal dashed line extending from the tip of the triangle."

πŸ“š Dataset

covaga/electrical-symbols-dataset β€” 33,502 EPLAN symbol images with short_name, catalog number, IEC/NFPA description, variant and visual_description. Trained on 24k samples, split by short_name so test symbols were never seen.

πŸ”Œ Recommended: pair with visual RAG for exact naming

Exact short_name recall needs retrieval, not memorization: embed the query image (CLIP/SigLIP), look up nearest neighbors in the symbol dataset, feed the real names as candidates. Related tooling:

🧩 Related models

πŸ‹οΈ Training details

Setting Value
Method Vision LoRA (Unsloth FastVisionModel), BF16
Layers tuned vision encoder + language attention/MLP (102M params, 1.07%)
Samples 24,000 image QA pairs, 1 epoch (1,500 steps, eff. batch 16)
Final loss 0.50 avg Β· 0.24 last quarter
Hardware A100 80GB, 2.3 h, 19.5 GiB VRAM peak

⚠️ Limitations

  • Weak on exact symbol IDs (1/24) β€” pair with image retrieval for production naming.
  • Long answers can burn the token budget on shape analysis before naming; give it β‰₯300 tokens or ask for the name first.
  • Isolated symbols only β€” it was not trained on full schematic pages.
  • Dataset noise exists (some auto-generated descriptions are garbled).
  • Not a replacement for EPLAN: verify against the official symbol library.
  • Base model Qwen/Qwen3.5-9B license terms apply.

πŸ“ Citation

@misc{eplan-2027-lora-vision,
  author  = {Lopez, Christian D.},
  title   = {EPLAN Electrical Symbol Recognition β€” Qwen3.5-9B Vision LoRA},
  year    = {2026},
  url     = {https://huggingface.co/covaga/eplan-2027-lora-vision}
}

Part of the covaga.xyz open EPLAN tooling β€” free Spanish EPLAN scripting guide, RAG endpoints, datasets and models.

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