We will now look at the BRX Do-More HTTP JSON instructions in the PLC. One of the features of the BRX Do-More 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 Do-More PLC can do very well. As part of the internet of things (IoT), the BRX Do-More 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) Do-More JSONPARSE – Parse JSON Text (BRX only) Do-More
We will be using these instructions to read the weather conditions from a website. Let’s get started. Continue Reading!
Data logging does not have to be complicated anymore. The BRX Do-More Series PLC can log your specific data up to 32 Gigabits on a Micro SD Card. It will store your data for future data analysis in a CSV (Comma Separated Value) Txt file based on time and/or event.
This is all accomplished with just one instruction in the BRX PLC. Excel is just one program that you can import and analyze this CSV Text file.
Do-More Designer has a Browse PLC File Systems window that will allow you to copy, create and delete the files from the connected computer. This will save you from going to each controller, removing and copying the files on the Micro SD Card.
We will be looking at the data logging instruction in the BRX Series PLC and how to retrieve and view this information. Let’s get started. Continue Reading!
We will now look at using serial Modbus RTU to communicate to a Solo process temperature controller using our BRX Do-More Controller. Serial communication instructions will allow you to send and receive serial data to an external device. The communication method that you setup can be ASCII or numeric (binary). ASCII (American Standard Communication for Information Interchange) can be used to send to devices such as a printer or display.
Receiving ASCII can be used for connecting barcode scanners to the PLC. The barcode will be read as an ASCII string in the PLC.
The BRX Do-More Series PLC will allow you to use instructions such as STREAMIN and STREAMOUT to send and receive data from devices mentioned above. They are usually a one to one device and do not have a protocol.
A protocol is like a language used to communicate to different devices connected together. Modbus serial communication (Modbus RTU) is a standard protocol used in many industrial automation devices. The BRX Do-More Series PLC has a MRX (Modbus Network Read) and MWX (Modbus Network Write) instructions.
We will demonstrate these instructions by communicating Modbus RTU to a Solo Temperature Controller. (RS485) Our example will read the current process (PV) value and write the set point value (SV) in the controller. Let’s get started. Continue Reading!
We will now look at the drum instruction in our BRX Do-More Controller. Drum instructions are great tools when you have a simple sequence of events that need to occur at a set time interval or as a result of an event. They mimic an electromagnetic drum sequencer. The BRX Series PLC has a drum in the instruction set.
Have you ever seen the mechanisms of a music box? Ok, so it’s a little drum with pegs that catch and flick the chimes in a particular sequence to play whatever tune is on the drum. So in the PLC, you can have a drum driven by an event, (input from a limit switch or button), or by time.
We will discuss the drum instruction and look at an example of controlling traffic lights with a cross walk signal. Continue Reading!
We will now look at shifting instructions in the BRX Do-More controller. PLC shifting instructions will move bits in memory areas a fixed amount when instructed. Bits are on/off, 1 or 0, and are usually associated together to form a memory location. The memory location can be used for numbers or positions. PLC BITS NUMBERS AND POSITION is a post that will review the different methods that the PLC will interpret the information in memory
We will be looking at the shifting (moving) of the bits within the memory location in several different ways. ROTL rotate left, ROTR rotate right, Math shift left operator, Math shift right operator, Math unsigned shift right operator and SR shift register are some of the instructions in our BRX Do-More PLC that will shift bits.
Let’s look at some samples of each of the above-mentioned instructions. Continue Reading!
We will now look at program control in the BRX Do-More controller. 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 using a synchronous PLC Scan. Understanding the PLC program scan will explain the synchronous and asynchronous program scanning. Ladder logic programs get solved left to right, top to bottom. The result of the rung before is available for the next rung.
Using programs, tasks, and subroutines in our BRX Do-More Series PLC we can divide up our program into smaller segments. This will help when we troubleshoot the system in the field as the system integrator. Let’s look at some samples of each of the above-mentioned methods. Continue Reading!