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Sensirion HDLC Node

Node driver for Sensirion HDLC devices. This package is largely modeled after Sensirion/python-shdlc-driver: Python Driver for Sensirion SHDLC Devices.

Please note Mytos Bio has no affiliation with Sensirion.

Sensirion HDLC Node

Documentation

For basic module documentation please see Sensirion HDLC Node Documentation. This documentation is automatically generated code is committed to the main branch.

Limitations

Currently this package only includes commands to communicate with the Liquid Flow Sensor using the Sensirion RS485 and USB Sensor Cable. For more information on either of the products this package is designed to work with please refer to the following links.

Usage

Installation

Install using npm or yarn.

npm install @mytosbio/sensirion-hdlc
yarn add @mytosbio/sensirion-hdlc

Working example

To communicate with a sensor the interfaces port, connection and device are used. The port is responsible for sending a receiving data between the computer and sensor. The connection manages resending requests and checking that a full response is received. A device uses a connection to provide an API to the connected sensor.

Here is an example for the SLF06 flow meter measuring the fluid volume which has passed through the sensor. In this example the sensor cable totalizer is used to collect the instantaneous flow measurements over a period of time. Then once 1000ms has passed the totalizer value is read from the sensor.

import {
  SerialPort,
  RetryConnection,
  FlowMeter,
} from "@mytosbio/sensirion-hdlc";

const measureInterval = 20;
const sensorPath = "/dev/sensor";
const sensorPort = new SerialPort(sensorPath, 115200);
const sensorConnection = new RetryConnection(sensorPort);
const sensorDevice = new FlowMeter(sensorConnection);

const main = async () => {
  await sensorPort.open();
  await sensorDevice.init();
  const productName = await sensorDevice.getProductName();
  console.log("productName", productName);
  await sensorDevice.startRecordingVolume(measureInterval);
  await new Promise(resolve => setTimeout(resolve, 1000));
  const volume = await sensorDevice.stopRecordingVolume(measureInterval);
  console.log("volume", volume);
  await sensorPort.close();
};

main();

Development

Please feel free to fork and modify this code. We have attempted to add some basic code quality checks to the process. When creating commits the Typescript files are built and linted to check they conform to the correct standards. If using VSCode then we highly recommend installing the prettier and eslint extensions.

For more details on how to contribute to this project please see [Contributing][contributing.md] guidelines.

Running tests

There are extensive tests to assert correct functionality. The test runner used is jest which accepts a number of arguments to watch the test files and filter tests based on filename. The following command will run all the tests for the repository.

yarn run test

Building documentation

Documentation can be built using typedoc.

yarn run typedoc

License

Please see LICENSE.