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Skill/references/schlib_parameters.md

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Mandatory symbol parameters (.SchLib)

Vecmocon's Altium SOP (§5) requires every schematic-library symbol to carry a fixed set of parameters in its component properties (the panel shown in Altium: Properties → Parameters). This file defines that set, where each value comes from, and how the skill stamps them onto the .SchLib symbol.

How the parameters get in: the skill writes them directly into the .SchLib in pure Python via scripts/schlib_write.py — it rebuilds the OLE compound file around the enlarged component Data stream while preserving every other byte (all other streams, the directory tree, the Altium CLSIDs). It also removes the Ultra-Librarian default params Manufacturer_Name and Manufacturer_Part_Number (which duplicate the SOP Manufacturer / Manufacturer Part), the UL Copyright notice (Vecmocon symbols don't carry it), and the UL Component_Type (underscore) — replaced by Vecmocon's own spaced Component Type parameter (see below). The output is a ready .SchLib. Because this writes Altium's own format from outside Altium, the script self-checks that the result re-opens as a valid OLE with the params present — but always open the result in Altium once to confirm it loads before relying on it. (An older path, scripts/altium_params.py, instead emits an Altium DXP script to stamp the same parameters from inside Altium; keep it as a fallback if a particular file doesn't round-trip.)

The parameter set

Use these exact Altium parameter names (they must match the symbol, per the SOP screenshot). The Comment field is set to the MPN (SOP §4), and the Description field is the strict string from references/description_format.md — which overwrites whatever prose Ultra Librarian put in Description (UL's text is often wrong: a real 6N137 export read SMD-8 CPLR SNGL 10MBD 100V/us -e3 when the datasheet CMR is 1000 V/µs).

Beyond this SOP set, also stamp on every engineering parameter from the part's typeid sheet (for an ISO: Isolator Type, Isolation Voltage, No. of Channels, Data Rate, Supply Voltage, Creepage, Package, Power, Max Output Current). Skip the housekeeping columns (MPN_make_type, Skill/Template Version) and the four Library/Footprint Ref/Path columns — Altium already holds those as the symbol's model links, so repeating them as parameters makes two sources of truth.

Encoding gotcha: Altium parameter records are latin-1, so a value containing ≥, ≤, ±-beyond-latin1, µ (U+00B5 is fine, U+03BC is not) or similar will crash schlib_write.py with a UnicodeEncodeError. Rephrase into latin-1 (≥ 7 mm → 7 mm min.) rather than dropping the value; ° (U+00B0) is latin-1 and safe. The workbook keeps the original notation.

Parameter Source Notes
Component Type derived the part's Class — Resistor, Capacitor, Diode, Transistor, IC, … — from the taxonomy row for its typeid (scripts/common.py:class_folder(typeid))
Value datasheet the component value only (no package), in shorthand — e.g. 1u, 12p, 100n, 10k
Manufacturer Part datasheet the MPN; also the Comment field
Manufacturer datasheet manufacturer name as printed, e.g. YAGEO
Manufacturer Part 2 leave blank (for now) second-source MPN — left empty by default; see optional note below
Manufacturer 2 leave blank (for now) second-source manufacturer — left empty by default
Process derived assembly process from package: SMD → Reflow, through-hole → Wave/Manual; confirm
Vecmocon Part Code engineer internal code (e.g. VECESC2421) — not on the datasheet; ask
Operating Temperature datasheet full range, e.g. -55 °C to +125 °C
Tolerance datasheet e.g. 1% (or ±1%)
Datasheet datasheet source URL or document reference (SOP marks this optional)
ROHS datasheet RoHS compliance, Yes/No

Read the datasheet-sourced values from the actual datasheet — don't echo whatever text was handed to you. Open the PDF, find each real value (Value, Manufacturer Part, Manufacturer, Operating Temperature, Tolerance, Datasheet, ROHS, and Process by inference from the package), and fill them verified. An honest blank beats a guess — the SOP hides blank parameters, so a gap just stays empty until someone fills it. Only one field is purely internal and is never on a datasheet: Vecmocon Part Code. Use it if the engineer already supplied it; otherwise leave it blank and note the gap in your summary — don't stop to ask. Stamping the symbol is automatic and non-interactive (SKILL.md, step 6), so no field blocks it.

The second-source pair (Manufacturer 2 / Manufacturer Part 2) is left blank for now — don't populate it by default. It simply stays hidden in Altium until someone fills it later.

Optional: second-source cross-reference (currently off)

House preference right now is to leave Manufacturer 2 / Manufacturer Part 2 blank, so do not do this unless the engineer explicitly asks you to find a second source. It's documented here so it can be switched on later without redesigning anything.

If asked to find a second source, it is an equivalent part from a different manufacturer that could drop into the design unchanged:

  1. Pull the original's form-fit-function specs from the datasheet — capacitance, voltage, tolerance, dielectric/temp class, package (for a cap); resistance, power, tolerance, package (for a resistor); and so on per type.
  2. Search for an equivalent from a different manufacturer (distributor/parametric cross-reference, "equivalent to <MPN>", or another reputable maker's matching series). It must match every form-fit-function spec and be at least as good on tolerance / voltage / temperature — never worse.
  3. Fill Manufacturer 2 = its maker, Manufacturer Part 2 = its exact MPN.

Two hard rules if this is ever used: never invent an MPN (only a part number you verified exists; else leave blank), and always flag the chosen second source for the engineer to confirm with the specs you compared.

Building the parameter set

Collect the values into a params.json (same spirit as part.json). component is the symbol's Library Ref (from altium_refs.py); omit it to apply to every component in the lib.

{
  "component": "CC0402FRNPO9BN120",
  "comment": "CC0402FRNPO9BN120",
  "parameters": {
    "Component Type": "Capacitor",
    "Value": "12pF_0402",
    "Manufacturer Part": "CC0402FRNPO9BN120",
    "Manufacturer": "YAGEO",
    "Manufacturer Part 2": "0402N120F500CT",
    "Manufacturer 2": "Walsin Tech Corp",
    "Process": "Reflow",
    "Vecmocon Part Code": "VECESC2421",
    "Operating Temperature": "-55 °C to +125 °C",
    "Tolerance": "1%",
    "Datasheet": "https://www.lcsc.com/datasheet/C326662.pdf",
    "ROHS": "Yes"
  }
}

Writing them into the symbol

Write the parameters straight into the .SchLib, producing a new file:

python scripts/schlib_write.py --schlib <in>.SchLib --params params.json --out <out>.SchLib

params.json may carry a "remove" list (defaults to ["Manufacturer_Name", "Manufacturer_Part_Number", "Copyright", "Component_Type"]); those Ultra-Librarian defaults are stripped and the SOP params — including the spaced Component Type = Class — added. Real UL exports also ship placeholder params whose Text is just the name back again (Type = Type, RefDes = RefDes, sometimes TYPE); add those to remove too — they're noise, not data. After writing, grep the output for Ultra Librarian / Manufacturer_Name and confirm the count is 0. The script targets the component named in "component" (its Library Ref / storage name), or every component if omitted, and self-checks the output re-opens as a valid OLE. Deliver the resulting .SchLib, and have the engineer open it in Altium once to confirm it loads, then Save to Server with a revision note per the SOP.

Scope note: the d