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 BRX PLC (Do-More). Let’s get started! Continue Reading!
One of the features of the BRX Series PLC is the ability to expand its capability to fit your application. Software and hardware changes are ongoing so the PLC can grow with your needs. Communication is something that the BRX PLC can do very well. As part of the internet of things (IoT), the BRX will share and exchange data. You can also refer to this as the industrial internet of things. This will suit several industrial applications.
The Do-more Updates Release 2.5.2 on April 22, 2019, has introduced new instructions. Here are the instructions that we will be using:
HTTPCMD – HTTP Request / Response with Server (BRX only)
JSONPARSE – Parse JSON Text (BRX only)
We will be using these instructions to read the weather conditions from a website. Let’s get started. Continue Reading!
PID Ramp Soak Instruction
The purpose of a ramp soak instruction is to make gradual, controlled changes in temperature (Ramp), followed by a temperature hold (Soak) period.
We will be using our Proportional-Integral-Derivative PID Instruction that we looked at last time to apply the ramp/soak instruction.
Using the immersion heater in a cup of water to keep the temperature at a constant value, we will be adjusting the profile of the temperature as we increase the set point (Ramp) and hold that set point for a predetermined time. (Soak)
We will be modifying our existing program from our PID loop instruction. Let’s get started. Continue Reading!
PID Loop (PID) Instruction (Auto Tuning)
A Proportional-Integral-Derivative algorithm is a generic Control Loop feedback formula widely used in industrial control systems. A PID algorithm attempts to correct the Error between a measured process variable and the desired setpoint by calculating and then outputting a corrective action that can adjust the process accordingly and rapidly, to keep the Error to a minimum.
The following links will explain the PID instruction.
We will be using an immersion heater in a cup of water to keep the temperature at a constant value. Using the Productivity Suite software we will perform an autotune on our PID instruction.
Our immersion heater will be controlled through a relay using time proportional control from our PID output. Let’s get started. Continue Reading!
Secure PLC Email messaging is now available in the latest version of the Productivity Programming suite. SMTP or Transport layer security (TLS) email with an attachment and/or latest data log files can be sent. To be able to use this feature you must have installed Productivity programming suite v3.4 or higher and then load the latest firmware to the Productivity CPU. We can set up 4 different accounts in our PLC project. Account templates are already installed for some of the more common email servers.
We will be sending an email using a Gmail account with authentication. This will also include attached logged data files, error and event files. Our message will also include a switch and register current values when sending our email. We will also discuss how the PLC can send a text (SMS) message. Let’s get started. Continue Reading!
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 Productivity 1000 Series PLC.
Our sample Productivity 1000 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 Productivity 1000 PLC. We will be able to monitor our process via the AdvancedHMI window. Let’s get started.
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 firmware for the productivity series of PLC’s must be downloaded separately from the programming software.
We will be updating our firmware of our Productivity 1000 PLC from 126.96.36.199 to the latest version 188.8.131.52. Let’s get started. Continue Reading!
The productivity series of PLCs comes with 4 built-in communication ports for easy connectivity to your PC or various industrial networks. Ethernet protocols like Modbus TCP can be utilized with the RJ45 port on this PLC. Modbus TCP is an open (published) protocol that uses the Server (Master) / Client (Slave) architecture. It’s a very common protocol used in industrial automation controls.
We will be using the RJ45 (Ethernet) port to communicate to a Click PLC. Modbus TCP will be the protocol used on this Ethernet communication media. The Productivity 1000 PLC will be the server and the Click PLC will be the client. We will be creating a network between the two PLC units. A heartbeat will be used so if communications is lost, the server (slave) will know. The throughput time will be timed by using a small program in the Click PLC. You will soon see how the Productivity Series of PLC’s is the best way to handle communication to other devices. Let’s get started. Continue Reading!
The productivity series of PLCs comes with 4 built-in communication ports for easy connectivity to your PC or various industrial networks. Serial protocols like Modbus RTU can be utilized with either the RS232 or RS485 ports on this PLC. Modbus RTU is an open (published) protocol that uses the Master / Slave architecture. It’s a very common protocol used in industrial automation controls.
We will be using the RS485 (2-wire) port to communicate to a Solo Process Temperature Controller. Modbus RTU will be the protocol used on this serial communication media. The PLC will be the master and the Solo process temperature controller will be the slave. You will soon see how the Productivity Series of PLC’s is the best way to handle communication to other devices. Let’s get started. Continue Reading!
The productivity series of PLCs has a built in web server. This web server function can make a non secure (HTTP) connection to the CPU. This is done with your browser. You can then view read only system tags and open, save or delete files stored on the micro SD drive.
Previously we stored data logged files on the USB (Micro SD) storage device. We will now start and configure the web server function. Look at the files from our data logger and view the system files available. Let’s get started. Continue Reading!