Category Archives: Modbus RTU

Serial communication protocol. This is usually RS232 or RS485.

CH340 CH341 USB to Serial PC Installation


We will be installing a USB to rs485 installation on our computer. The CH340/CH341 USB to Serial port is a 2-wire USB to RS-485 serial communication adapter for RS485 use. It does not require an external power supply or complicated configuration.

It has a Type A (plug) USB connector for the computer side and screw terminals for the RS485 connections. The CH340/CH341 USB to serial device supports multiple baud rates and has a thumb drive design.  Let’s get started installing our USB to RS485 adapter. Continue Reading!

Node-RED SQL Database Spreadsheet Connection


We will now look at the connection to our SQL database using a spreadsheet application. Previously we used Node-RED to communicate Modbus TCP and RTU to our Click PLC and Solo Temperature Controller. The information collected from the controllers was then put into an SQLite SQL database.

Spreadsheets like Excel are great for analysis of the data. We will be connecting to our SQLite SQL database with WPS spreadsheets. This will be accomplished by using an ODBC driver as the translator between the database and spreadsheet. Let’s get started. Continue Reading!

Node-RED SQL Database Log – Modbus Logging


Node-RED can easily log data to a database. SQL (Structured Query Language) can be used to communicate to a SQL database. Databases separate analysis from the data unlike spreadsheets like Excel. The database is designed to hold more information than spreadsheets and allow multiple users to access the information.

We will be creating an SQLite SQL database. SQLite Studio will be used to design the structure of the database. (Tables) Installing the node-red-sqlite-node palette will allow us to log the information from our Solo process temperature controller, Click PLC, and dashboard variables. Let’s get started. Continue Reading!

Click Plus Establish Communication


We will now establish communication using four different methods from our computer to the new Click Plus controller. The click programming software version 3.00 will be used for the communication methods. Click Plus controllers allow you to program them through the micro USB port on every CPU. WiFi (Bluetooth Provisioning) is also available on some controllers. Ethernet and Serial ports may also be used for programming if they are present on your model of Click Plus.

We will be establishing PC to PLC communications using version 3.00 of the click programming software. Four different ways will be discussed on getting connected to the Click Plus controller to program. Let’s get started. Keep on Reading!

Node-RED User Interface – Dashboards


Node-RED can easily display interactive information to the user or operator using a web browser on your phone, tablet, or computer. Any device that has access to the network in which node-red is running.
We will be installing the node-red-dashboard palette. This allows us to create a live data dashboard user interface. (UI)

The information from our Solo process temperature controller will be displayed. Setpoint information can be set either by the dashboard UI or the Click analog input signal. This will be selected via the user interface. Let’s get started using Node-RED Dashboards. Continue Reading!