Tag Archives: programmable logic controller basics

Click PLC Real Time Clock (RTC) – Ladder Logic


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)
click plc real time clock
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!

Click PLC Modbus ASCII Protocol Communication


We will now look at the click plc modbus ascii protocol. This communication will happen in PLC ladder logic and communicate through the serial port (RS485) to a Solo process temperature controller. Modbus ASCII will be the communication protocol.
Modbus is a communication method used for transmitting information over serial lines between electronic devices. The device requesting the information is called the Modbus Master (Client) and the devices supplying information are Modbus Slaves (Servers). This protocol was originally developed by Modicon systems.
Modbus protocol comes in basically three different types. Ethernet (Modbus TCP) or Serial (Modbus RTU or Modbus ASCII). Modbus TCP and Modbus RTU come as standard protocols in the productivity series of PLCs.
click plc modbus ascii
We will connect the Click PLC to a Solo process temperature controller. This will be done using the Modbus ASCII protocol over serial RS485 communication wire. (Media) The present and set values (PV / SV) will be read from the Solo controller and the set value will be written when required. Let’s get started. Keep on Reading!

Click PLC PID using Factory IO (3D)

A PID (Proportional, Integral, and Derivative) control is possible with the Click PLC. A sample program was written for this PLC by Bernie Carlton in the following thread from the Automation Direct Forum. This was based on the math/process presented by Tim Wescott on is paper titled PID without a Ph.D. We will be using this sample program along with a Factory IO scene to demonstrate PID control using our Click PLC.
Click PLC PID using Factory IO
Here are some references on PID control:
PID without a Ph.D. By Tim Wescott
Understanding PID in 4 minutes
PID Control – A brief introduction
PID Controllers Explained
Who Else Wants to Learn about On-Off and PID Control?
Our Factory IO scene will be controlling the level of water in a tank. PID will be used to maintain the level based on a dial pot knob on the control panel. We will also discuss the math that the PID loop uses. Let’s get started! Keep on Reading!

Wiring Stack Light to a Click PLC

We will now wire a stack light to the Click PLC. Stack lights are usually modular stackable components that provide a visually illuminated and audible indication for machines, systems, and processes. They are usually located on top of equipment to provide this notification to personnel in the area.

Stack lights are also known as signal tower lights, indicator lights, warning lights, industrial signal lights, tower lights, and light towers.
We will be connecting a Patlite NPS-402-RYGB Super Slim stack light to our Click PLC.
Wiring Stack Light to Click PLC
These stack lights come in preassembled units in the most popular combinations of colours with ABS resin main bodies that offer superior impact and heat resistance; double-insulated construction enhances durability and safety. Interchangeable light modules require no rewiring. Let’s get started. Continue Reading!

Click PLC High Speed Counting – Part 2

The Ethernet Click PLC high speed counter has seven different modes of operation. In Part 1 we discussed the High Speed Count Mode, Interval Measurement Mode,
Duration Measurement Mode and Frequency Measurement Mode.
Click PLC High Speed Counting – Part 2
This 100 KHz counter can accept Up, Down, Up/Down, Pulse/Direction or Quadrature (with Z) inputs.
We will be looking at the last three different high speed counter modes available in the click. (External Interrupt, Pulse Catch, Filter) This is all setup through a user friendly graphical user interface. We will also combine the Frequency Measurement and the High Speed Count in one application. Let’s get started! Keep on Reading!