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!
Node-RED can easily connect to industrial controls using Modbus communication. Modbus is a master-slave type of communication. Masters will always send the commands to read or write to the slaves on the network. The slaves will respond if the communication is directed at them.
We will be installing the node-red-contrib-modbus palette. This will allow us to communicate Modbus serial (RS485) RTU to a Solo process temperature controller. We will then use Modbus Ethernet TCP to communicate to a Click PLC.
Note: When using Modbus TCP (Ethernet) the master is referred to as the Client and the slave is a Server.
Node-RED will be used to create a single Modbus flow. We will communicate to our Solo process temperature controller using Modbus RTU on a serial RS485 network. The present and set values of the controller will be read. These values will then be written to our Click PLC using an Ethernet Modbus TCP network. A set value from an analog input on the Click will be used to then write to the Solo. This will happen every 200 milliseconds or 5 times per second.
Let’s get started using Node-RED for Modbus communication. Continue Reading!
We will now be installing the Node-RED software on our Windows 10 computer. Node-RED is a powerful and easy programming tool that will allow you to join together hardware devices, APIs (Application Programming Interface), and online services. This joining of information is part of the smart factory. Internet of Things (IoT), Industrial Internet of Things (IIoT), Industry 4.0, and Smart Production are just a few of the other labels that have been applied to this type of technology.
Node-RED provides a browser-based flow editor. This provides an easy way to visually see and modifies your program flow. Flows can then be deployed to the runtime in a single click. Node-RED is built on Node.js. This lightweight runtime can be deployed on low-cost hardware (Raspberry Pi ) or cloud services (Microsoft Azure). This has the ability to bring data collection, analysis, and storage closer to the actual device. Real-time edge computing can then be achieved without latency issues.
In this series we will be using Node-RED in some of the following ways:
– Connect to our industrial equipment using the Modbus protocol.
– Display Information on a user interface, HMI, or dashboard
– Log information into a database
– View information in the database through spreadsheets such as Excel.
Let’s get started by installing Node-RED. Continue Reading!