Category Archives: Modbus TCP

Ethernet communication protocol. This is part of the Modbus.

C-More Drop-Down Menu Create – All Models


The C-More can create a drop-down menu. This applies to all models of the HMI controller. A drop-down is a menu that offers a list of options. The currently selected item in the list is always displayed. When the visible item is selected (touched), other items from the list “drop-down” into view, and the operator can choose from those options.
C-More Drop-Down Menu Create
We will be creating a drop-down menu using a C-More Micro HMI. (Human Machine Interface) This could also be done using the EA7 or EA9 C-More HMI controllers. The EA3-T4CL will be communicating to a Click PLUS PLC. A ladder logic program in the PLC will control the operation of this operator interface drop-down menu. Selecting a question on the drop-down will give an answer on the corresponding Lookup Text display. Let’s get started. Continue Reading!

Node-RED Modbus TCP Handling Errors


Node-RED Modbus TCP can recover from communication errors automatically. Options are available to you the programmer to continue the Node-RED flow upon detection of these errors.

Broken Ethernet cable, Modbus Server power, and Node-RED Client offline are just a few of the errors that can occur on the industrial plant floor. Our Node-RED program must account for and be tested for each of these conditions.
We will be communicating Modbus TCP (Ethernet) to our Click Plus PLC. Using the catch node we will detect and display errors that may occur. Let’s get started. Continue Reading!

Simple Click Data Logging – Node-RED


We will now be looking at simple data logging using a Click PLC with an Ethernet port. Node-RED will be used to communicate to the controller via Modbus TCP protocol. Information collected will be then stored in an SQLite SQL database. A Raspberry Pi 4 single-board computer will be used for the Node-RED collecting and storing. The update time will be two times a second (500 mSec). This method is ideal for quickly determining how things are operating.

Analysis or display of the information will be done with a spreadsheet. The spreadsheet will be run on a windows computer. Let’s get started. Continue Reading!

Do-More PLC Node-RED HTTP Request


Node-RED HTTP Request can be used to read any BRX Do-More PLC memory area. This HTTP (Hypertext Transfer Protocol) communication will only read information from our controller.
Do-More PLC Node-RED HTTP Request
The BRX Do-More REST API is used to read information using a URL (Uniform Resource Locator) or web address. We will be using the HTTP request node in Node-RED to read information from our BRX Do-More REST API-enabled controller. Writing using Modbus will also be shown. This will all be done on our Raspberry Pi 4 single-board computer. Let’s get started. 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.
Node-RED SQL Database Spreadsheet Connection
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!