The Click PLC retentive data memory registers are not included in the program file by default. All Click PLC CPUs are included. This option must be selected to include the C, CT, DS, DD, DH, DF, CTD, and TXT memory in the Click project file.
We will be enabling the option to include the retentive data memory in the Click program file from the Click programming software. We will also be installing a battery and programming an expiry date. This will indicate when the battery will need to be replaced. Let’s get started. Keep on Reading!
EasyPLC Software Suite is a complete PLC, HMI, and Machine Simulator Software package. This PLC learning package includes a Machine Simulator (MS). This virtual 3D world with real-time graphics and physical properties can communicate to several different programmable logic controllers. (PLC)
We will be developing a Click PLC program for a transfer line. This is just one of the prebuilt machines in the simulator to learn PLC programming. We will be developing the ladder logic, connecting via Modbus RTU, and testing our program. This will be done using the five steps to PLC program development. Let’s get started! Keep on Reading!
Many questions come from serial communications using the Click PLC. Most of these questions deal with communication timing when using multiple send and receive instructions. We will show you how to deal with serial communication timing in the Click PLC.
Receive and Send instructions will allow you to send and receive serial data to an external device. The communication method that you set up can be ASCII or Modbus. ASCII (American Standard Communication for Information Interchange) can be used to send to devices such as a printer. Receiving ASCII can be used for connecting barcode scanners to the PLC. The barcode will be read as an ASCII string in the PLC. Modbus serial communication (Modbus RTU) is a standard protocol used in many automation devices.
We will demonstrate the Send and Receive instruction by communicating Modbus RTU to a Solo Temperature Controller. Parameters from the Solo process temperature controller will be read using multiple receive instructions. The send instruction will be used multiple times as well to set the Set Value (SV) and Limits of the SV value entered in the temperature controller. The set values will only be changed when required. Let’s get started. Keep on Reading!
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 that we can turn on and off based on the time change in the area.
We will be setting up the network time service on our Click Plus. The real-time clock (RTC) will be updated via the internet time service. Daylight savings time and the RTC will also be programmed. This will be based on our previous Click Real-Time Clock post. Let’s get started. Keep on Reading!
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!