Practical Tips and Techniques
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 … Read more
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 … Read more
The real-time clock on the Click Plus can now be more accurate. A network time service (NTP or SNTP) has been added to the Click Plus controller. This will allow the time to be synchronized with an internet time server or local network. Daylight savings time is quickly implemented with just a memory retentive bit … Read more
We will now look at the data logging capability using our Click plus PLC. Data logging is the collection of data over time. This is usually used for data analysis at a later time. The amount of data (System Information) stored and the frequency of the storage will depend on your specific application. The hardware … Read more
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 … Read more
We will now look at the MQTT communication capability using our Click plus PLC. MQTT stands for Message Queuing Telemetry Transport. This simple ‘publish and subscribe’ communication protocol, does not take too many resources. Constrained devices with low bandwidth are ideal for MQTT. This protocol provides machine-to-machine (M2M) connectivity which is ideal for the Internet … Read more