Table of Contents

Introduction:

What is Tentacle PLC?

Tentacle PLC is a modern Soft PLC runtime with the basic features of a traditional programmable logic controller platform, but the process logic is written in Javascript.

Excerpt from Tentacle PLC Guide

Why am I testing Tentacle PLC?

  • I am taking a full-stack engineering program and learning JavaScript. So, I thought this would be a good opportunity to continue developing my skills while testing out what I believe is a great soft PLC project.

Hardware:

Hardware I used:

Software:

Documentation:

Steps Taken:

Ubuntu Set-up:

Docker Set-up:

Container urls:

  • Tentacle PLC
    • http://localhost:4000
  • Tentacle PLC UI
    • http://localhost:3000
  • Code Server
    • http://localhost:8080
    • Note: I got this message when I tried accessing the Code server: image
    • See Determine Code Server Password to learn how I retrieved the password

Determine Code Server Password:

  • I followed the instructions on this link
  • Identify the container id with sudo docker ps:
  • Pass /bin/bash as the argument with -it option to docker exec docker exec -it [CONTAINER_ID] /bin/bash:
  • Change directory to config.yaml file location cd ~/.config/code-server:
  • Print config.yaml file contents to terminal cat config.yaml:
  • Copy the password from the terminal

PLC Programming Steps:

  • The goal was to get a simple PLC program working and connect to a MQTT broker.
  • After the installation and configuration, it didn’t take long to achieve this goal
  • To start programming I went to the code-server url http://localhost:8080 and enter password. See determine code server password
  • Followed the Tentacle PLC Guide to create a test program

Configure config.json:

  • I copied the example config.json code in the Tentacle PLC Guide
  • I modified the MQTT configuration and put in the credentials for my HiveMQ Cloud Broker
  • I left the modbus section empty as I don’t have a modbus device at the moment. This section is for configuring the connection to a Modbus Remote IO device

Configure variable.json:

  • I copied the example variables.json code in the Tentacle PLC Guide
  • I commented out the modbus variables and motor variable (lines 14-85) as I don’t have a modbus device connected

Configure programs:

  • I created 2 files:
    • main.js
    • secondary.js

Files used in program:

Summary:

  • The initial installation and configuration took the most time as I am not too familiar with docker
    • After this project, I am definitely more confident but have much more to learn
    • I am sure others will find the configuration process quite straightforward
  • After the installation and setup, the programming portion was very nice and straightforward
  • The PLC programming portion is well documented and I was able to get a simple PLC program running
  • I like the GraphQL API capabilities
    • The PLC stopped running and I was able to restart the PLC using the restartPlc GraphQL mutation
  • I like that each variable in variables.json is published using the Sparkplug B specification
  • The UI is nice. See image below: image

Next Steps:

  • Integrate the Tentacle PLC with Ignition
  • Create a more complex PLC program for a real world application
  • Connect Remote IO

Comments

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