Node-RED will be used on the Raspberry Pi 4 to communicate serial Modbus RTU to a Solo process temperature controller and Click PLC using twisted pair RS485. This will be done on the same serial network so the devices will be daisy-chained together on the two wires.
We will be reading the PV (present value) and SV (set value) of the Solo temperature controller and then writing these values into the Click PLC. An SV value will then be read from the Click PLC and if it has changed, the value will be written to the SV of the Solo controller. Let’s get started. Continue Reading!
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!
We will now be installing Node-RED on a Raspberry Pi 4 single-board computer. A static IP address will also be given for both the WiFi and Ethernet connections.
The Raspberry Pi has quickly become a fixture in the industrial environment when utilizing the internet of things. (IoT) We will be utilizing this low-cost computer to poll and log information from our PLCs using Modbus and MQTT protocols. Node-RED will be the IoT enabling software that will allow us to utilize this hardware.
Let’s get started with installing Node-RED and setting up a fixed IP address on our Raspberry Pi 4 computer. Continue Reading!
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.
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!