Category Archives: Communication

Click PLC Serial Communication Timing


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.
Click PLC Serial Communication Timing
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!

Omron PLC Node-RED Serial Communication


PLC manufactures have their own proprietary protocols. These methods of communication will allow you to program the controller. Other protocols will allow you to collect and log information from the programmable logic controller. Node-RED has the ability to read and write to the Omron controller using special protocol commands.

We will connect Node-RED to the Omron CP1H PLC. A serial RS485 interface will be used for communication to the industrial controller. We will demonstrate reading and writing using Host Link (C-mode commands) to the Omron PLC. Let’s get started. Continue Reading!

C-More Micro Program Quick Start


We will now look at the C-More Micro program quick start. This will demonstrate how to quickly get your C-More Micro Program up and communicating to your programmable logic controller. (PLC)

The general steps involved with a human-machine interface (HMI) program will include, program development, ladder logic, and HMI program development. We will be breaking the HMI program development into program purpose, tag import, HMI programming, simulation, and testing.
An EA3-T4CL C-More Micro HMI will be used to communicate to a Click PLC via Ethernet. A Start/Stop circuit will be programmed with a Timer. This can be controlled via the PLC inputs or HMI inputs. The timer present value (PV) will be shown on the HMI. The set value (SV) of the timer can be changed using the HMI. Let’s get started. Continue Reading!

C-More Drop-Down Menu Create – All Models


The C-More can create a drop-down menu. This applies to all models of the HMI controller. A drop-down is a menu that offers a list of options. The currently selected item in the list is always displayed. When the visible item is selected (touched), other items from the list “drop-down” into view, and the operator can choose from those options.

We will be creating a drop-down menu using a C-More Micro HMI. (Human Machine Interface) This could also be done using the EA7 or EA9 C-More HMI controllers. The EA3-T4CL will be communicating to a Click PLUS PLC. A ladder logic program in the PLC will control the operation of this operator interface drop-down menu. Selecting a question on the drop-down will give an answer on the corresponding Lookup Text display. Let’s get started. Continue Reading!

Raspberry Pi Serial Port Programming


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!