The Do-More Designer Programming Software (2.9) or higher includes a Modbus I/O Scanner with some profiles for Modbus Server (Slave) devices. This will greatly reduce the time it takes to implement and troubleshoot communications in your projects. Modbus communications are done independent of the PLC scan time and will have little or no ladder logic for the program.
Last time we communicated to a Solo process temperature controller via Modbus RTU RS485. (twisted pair) We manually set the Modbus IO scanner, reading the present value (PV) and set value (SV) of the Solo. The writing of the set value (SV) located within the BRX Do-More controller was also done. This was all be done without using any ladder logic code. We will now use the Modbus profile in the Modbus IO Scanner to connect a Click Plus PLC to our RS485 network. Using the Modbus scanner to write and read instructions we will also show how to use the ladder logic code with our scanner. Let’s get started. Continue Reading!
The Productivity Series 2000 and 3000 CPUs and remote controllers have OLED/LCD displays. The data can be system errors and information or user-defined messages programmed through ladder logic. Operators, maintenance, or programmer can use this information for running conditions, troubleshooting, or other items for the PLC system.
We will be looking at the CPU OLED/LCD on the productivity 2000 PLC. The eight control buttons will display the inputs and output for troubleshooting. System parameters like the real-time clock can also be set using the CPU display and control buttons. Custom messages displayed will be programmed in ladder logic. This will include scrolling messages and displaying tag information. Let’s get started. Keep on Reading!
The newest version of the Do-More Designer Programming Software (2.9) includes a Modbus I/O Scanner. This Modbus scanner will simplify Modbus RTU serial communications to any device. Communications are done independent of the PLC scan time and will have little or no ladder logic for the program.
We will be communicating to a Solo process temperature controller via Modbus RTU RS485. (twisted pair) Setting up the Modbus IO scanner and reading the present value (PV) and set value (SV) of the Solo. We will also write the set value (SV) located within the BRX Do-More controller. Communications will happen without using any ladder logic code. Let’s get started. Continue Reading!
Previously we created our first program using the Productivity Suite Software and transferred this to our connected Productivity 2000 Series PLC. One of the most important aspects of programming the PLC is to document. This will aid you and your team in programming, troubleshooting, and modifying the automation control system. Your documentation should read like a book so information can be quickly obtained when required. Time spent on the PLC documentation will be priceless when you go to read your program in 1, 3, or 10 years from now. The Productivity Suite software provides several different methods for documenting your PLC program.
Tag Names and Details, Task Names and Descriptions, Rung Comments and Instruction comments are the ways that we will be looking at documenting our PLC program. Let’s get started. Keep on Reading!
The High-Speed Input Pulse Catch will set an output that can be seen by the PLC ladder logic scan in response to an input pulse. Inputs that are too fast to reliably be seen by the ladder logic scan time will be seen.
The BRX Do-More series of programmable logic controllers have built-in high-speed inputs. These inputs can function in Counter, Timer, or Pulse Catch modes. Every CPU will have either 6 or 10 high-speed inputs (HSI) available depending on the model. These inputs can be used for input frequencies from 0 to 250Khz. 250Khz represents 250000 input counts per second that can be coming from devices connected to your PLC like an encoder. Due to the speed of the inputs, they function on the BRX Do-More PLC asynchronous with the PLC scan time.
We will continue looking at the high-speed inputs on our BRX Do-More PLC, by looking at the pulse catch mode. The pulse catch mode will be set up using the Z phase of our incremental encoder. Pulses will be counted using the input directly in the ladder logic and using the pulse catch bit. Comparisons will be made between the two counts and an output will be turned on when different. Let’s get started. Continue Reading!
The productivity suite programming software has a debug mode. This will allow you to view and control the rung execution on your ladder logic code. These programming tools allow you to troubleshoot, find, and correct errors in the PLC programming logic.
We will be adding a couple of rungs to our exiting start-stop circuit we created last time in our productivity 2000 PLC. Using the debug mode we will explain the scan of the PLC and use these tools to sequence the logic. Let’s get started. Keep on Reading!