@kortoaus/cas-scale

A lightweight TypeScript library for interfacing with CAS PD-II electronic weighing scales over RS-232 serial communication.
Automatically requests and parses weight data from the scale, using the serialport package under the hood.

✅ Tested and confirmed to work with CAS PD-II in ECR-TYPE 2 (STX/ETX protocol mode) only.

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✨ Features

• ✅ Automatically sends weight request commands (W)
• ✅ Parses 7-byte responses from CAS PD-II scale
• ✅ Emits weight in kilograms via callback
• ✅ Works with Node.js & TypeScript
• ✅ Tiny, dependency-light wrapper

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📦 Installation

npm install @kortoaus/cas-scale

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🚀 Usage

import { initializeScale } from "@kortoaus/cas-scale";

initializeScale("/dev/tty.usbserial-B002EF3X", (weight) => {
  console.log("Weight:", weight, "kg");
});

Optional error callback:

initializeScale(
  "/dev/tty.usbserial-B002EF3X",
  (weight) => {
    console.log("Weight:", weight);
  },
  (err) => {
    console.error("Scale error:", err);
  }
);

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⚙️ Scale Setup Instructions

Ensure your CAS PD-II scale is configured as follows:

Setting	Value
ECR Type	2
Baud Rate	9600
Data Bits	7
Parity	Even
Stop Bits	1

To change ECR Type:

1. Turn off the scale
2. Hold ZERO + TARE and power on to enter setup mode
3. Navigate to Ecr setting and set to 2
4. Use TARE (long press) to save and proceed

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🧪 Tested On

• CAS PD-II with firmware version supporting ECR-TYPE 2
• macOS + USB-to-Serial adapter (FTDI, CH340 confirmed)
• Node.js 18+

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📝 License

MIT — © kortoaus