Tag Archives: modbus

Click PLC PID using Factory IO

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.

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!

Click PLC Analog Dusk to Dawn Program

A dusk to dawn sensor usually is discrete on/off of the lighting control. If we want to vary the lights to mimic more of the sunset and rise, we would use an analog output to control the lights. I was recently asked about such a program. Every day they wanted the lights to go off at 10 pm and come back on at 6 am. At 9:30 pm the lights would be on at 70% or 7volts of a 0-10V signal. In the next half hour, the program will bring the lights from 70% down to 0%. In the morning the lights will come back on within the half-hour from 0% to 70%. Poultry Farms are one place that would utilize this program.

We will be developing a program that will do this with our Click PLC. Let’s get started! Keep on Reading!

Click PLC Update Firmware

Firmware is usually PLC operating system code that is written into a read only memory. The BIOS (Basic Input Output System) of a PC (personal computer) is a good example of firmware. It provides the low level interface between the hardware and software. The Click PLC firmware comes with the programming software.
https://support.automationdirect.com/products/clickplcs.html

We will be updating our firmware of our Click PLC from 2.10 to 2.30. Let’s get started! Keep on Reading!

Suppanel Android HMI to Click PLC

Suppanel is an Android app that is used to create a human machine interface (HMI). This HMI panel can be created on your computer, tablet or phone using the appropriate operating system or software. You can use this software to create panels that you can control or modify values in your automated system. These panels can be shared with other Suppanel users.

We will be creating a Suppanel Panel to monitor and control a Solo Process Temperature Controller via the Click programmable logic controller (PLC). The Click will be communicating to the Solo with serial RS485 using Modbus RTU protocol. The Suppanel HMI will be communicating to the Click PLC using Ethernet Modbus TCP protocol.

Watch on YouTube : Suppanel Android HMI to Click PLC

Let’s get started. Continue Reading!

BRX PLC AdvancedHMI Communication – Modbus TCP

Advanced HMI is a powerful, adaptable HMI/SCADA (Supervisory Control and Data Acquisition) development package that takes advantage of Visual Studio. There is no coding required and you can simply drag and drop items onto the page. The best thing is that the software is free. We will look at using AdvancedHMI with the BRX Series PLC.

Our sample BRX PLC program will display a digital panel meter and a gauge of a value in the PLC. Stop and start momentary pushbuttons on the HMI will allow this number to increase or stop. An indication will turn green when the number is increasing and red when it has stopped. The AdvancedHMI package will communicate Modbus TCP over Ethernet to the BRX PLC. We will be able to monitor our process via the AdvancedHMI window. Lets get started. Watch on YouTube…
Continue Reading!

Modbus RTU Click PLC Master to BRX PLC Slave Communication

Recently I was asked to demonstrate communication between a Click PLC and BRX PLC using Modbus RTU. Both PLCs are available from automation direct com. Modbus serial communication (Modbus RTU) is a standard protocol used in many automation devices. It works on a Master / Slave configuration. You can have only one master per network on Modbus RTU (Remote Terminal Unit). A maximum of 32 devices (Nodes) on the network can communicate to the master. A review of the Modbus RTU protocol (RTU frames) can be seen at the following URL.
http://www.rtautomation.com/technologies/modbus-rtu/
Using the Click PLC as a Master we will be communicating to the BRX PLC (Slave). Our example will read 10 registers from the BRX PLC and write 10 registers to the Click PLC. Let’s get started! Keep on Reading!

Implementing the Solo Process Temperature Controller

The SOLO Temperature Controller is a single loop dual output process temperature controller that can control both heating and cooling simultaneously. It is available in 1/32, 1/16, 1/8 and 1/4 DIN panel sizes and is UL, CUL and CE approved. The name of temperature controller is deceiving. This unit will also accept voltage and current into them, which is great for process control.

Recently I was asked: How you can change the pressure value from PSI to Bar?

They were bringing into the controller a voltage signal. This can be scaled using the tP-H (High level signal) and tP-L (Low level signal). The units on the display scaled for you. The default is -999 to 999. See section 11-2 of the following information guide that comes with the controller. Continue Reading!

Click PLC Send and Receive Instructions

Receive and Send instructions will allow you to send and receive serial data to an external device. The communication method that you setup 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 to a Solo Temperature Controller. Our example will read the current process (PV) value and write the set point value (SV) in the controller.  Keep on Reading!

Click PLC Program Control Instructions

The program control instructions will allow us to specify what parts of the logic get solved and when this happens. This will control how the PLC will scan and solve your logic in your program.  Keep on Reading!

Click PLC Installing the Software

Previously we discussed the Click PLC System Hardware – Video. Today we will be installing the free software required to program the PLC. This includes the actual program and communication drivers.  Keep on Reading!