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 of Things. (IoT) This protocol is not for remote IO or real-time (deterministic) applications. MQTT is a good solution for applications that move data from hundreds or thousands of machines (sensors) to clients in many networks.
We will be installing a windows based broker called Mosquitto. The Click Plus PLC will be one of the clients publishing and subscribing to the MQTT broker. Node-RED will be the other client publishing and subscribing to the MQTT broker. Each client will share information. Let’s get started. Keep on Reading!
The Click Plus PLC has now been released. This can only be programmed with version 3.00 or higher of the Click Programming Software. Version 3.00 will program all of the Click PLC CPU units and add additional features to the Click Ethernet CPU units.
Features of the new Click PLUS PLC (C2-0xCPU) includes the following:
• Micro USB
• DHCP support
• DNS support
• Wi-Fi (programming and Modbus TCP)
• Bluetooth (Wi-Fi) provisioning
• SD Card (Data Logging)
• Data Logger
• Network Time Service
• MQTT (Publish/Subscribe)
• Required PLC Password
• Disable Ports
• Strong Password Support
• Disable Ping Response
• Encrypted Password Transfer
We will be installing version 3.00 of the Click programming software on our windows 10 computer. After starting the software we will review some of the new features. Let’s get started. Keep on Reading!
We will look at the BRX Do-More FTP (File Transfer Protocol) on our PLC. Using FTPGET and FTPPUT instructions we can transfer files to an FTP server. Our BRX Do-More PLC now has the ability to be an FTP Client. This will allow us to transfer our logged files to an FTP server that we programmed in the following post.
Data Logging – Video
As an FTP Client, the Do-More PLC now has the ability to transfer and retrieve files from the network at an appropriate time in the PLC logic.
We will be setting up a Windows 10 FTP server on our computer. Using the FTPPUT FTP Client command on our BRX Do-More PLC we will store a file on our FTP server. The FTPGET Client command instruction will be used to retrieve a recipe text file on our server. This recipe file will have three timers that we will be used in a sample program to turn on some outputs. Let’s get started. Continue Reading!
We will now look at the BRX Do-More PLC Web Server. Ethernet equipped BRX CPUs and the Do-More Designer Simulator can now have a web server. This can be accessed by any web browser using the IP address of the BRX Do-More CPU.
A web server is server software or hardware dedicated to running this software, that can satisfy client requests on an Ethernet network. A web server can contain one or more websites and websites can have several web pages. A web server processes incoming network requests over HTTP and several other related protocols.
The website built into the BRX Do-More has several different tabs that have basic information about the system, status information like warnings and errors, input and outputs, system logs, user logs, and user pages. We will be enabling the webserver on our BRX Do-More PLC and showing the information that is available. This is a great tool for troubleshooting the PLC as you will see. Let’s get started. Continue Reading!
The click plc has a real-time clock that will allow us to control outputs based on a date or time of day. This real-time clock (RTC) can be set from the click programming software or through the program of the controller. Our programs in the click can use the following calendar and clock values:
SD19 – RTC Year – 4 digits (2021)
SD20 – RTC Year – 2 digits (21)
SD21 – RTC Month – (00 to 12)
SD22 – RTC Day – (00 to 31)
SD23 – RTC Day of the Week – 1 Sunday to 7 Saturday
SD24 – RTC Hour – (00 to 23)
SD25 – RTC Minute – (00 to 59)
SD26 – RTC Second – (00 to 59)
We will be using the RTC – Real Time Clock in a sample program. This program will turn on an output Monday to Friday from noon until 1 pm. It will also adjust for daylight savings time. Let’s get started. Keep on Reading!