BRX Do-More PLC Serial Communication – Modbus RTU to Solo Controller

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 Series PLC will allow you to use instructions such as STREAMIN and STREAMOUT to send and receive data from the 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 Series PLC has 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 setpoint value (SV) in the controller. Let’s get started.

More information can be obtained at our website. This includes all of the links mentioned in this video.
https://accautomation.ca/brx-plc-seri...

Previously in this BRX Do-More Series PLC, we looked at the following:
System Hardware
http://accautomation.ca/brx-plc-syste...
System Hardware Video
   • BRX Do-More PLC System Hardware  
Unboxing Video
   • BRX Do-More Series PLC Unboxing  
Installing the Software
http://accautomation.ca/brx-plc-insta...
Installing the Software Video
   • BRX Do-More PLC Installing the Software  
Establishing Communication
http://accautomation.ca/brx-plc-estab...
Establishing Communication Video
   • BRX Do-More PLC Establishing Communic...  
Updating Firmware Video
   • BRX Do-More PLC Updating Firmware  
Numbering Systems and Addressing
http://accautomation.ca/brx-plc-numbe...
Numbering Systems and Addressing Video
   • BRX Do-More PLC Numbering Systems and...  
First Program
http://accautomation.ca/brx-plc-first...
First Program Video
   • BRX Do-More PLC First Program  
Monitoring and Testing the Program
http://accautomation.ca/brx-plc-monit...
Monitoring and Testing the Program Video
   • BRX Do-More PLC Monitoring and Testin...  
Online Editing and Debug Mode
http://accautomation.ca/brx-plc-onlin...
Online Editing and Debug Mode Video
   • BRX Do-More PLC Online Editing and De...  
Timers
http://accautomation.ca/brx-plc-timers
Timers Video
   • BRX Do-More PLC Timers  
Counters
http://accautomation.ca/brx-plc-counters
Counters Video
   • BRX Do-More PLC Counters  
High Speed IO
http://accautomation.ca/brx-plc-high-...
High Speed IO Video
   • BRX Do-More PLC High Speed IO  
BRX PLC Compare Instructions
http://accautomation.ca/brx-plc-compa...
Compare Instructions Video
   • BRX Do-More PLC Compare Instructions  
BRX PLC Math Instructions
http://accautomation.ca/brx-plc-math-...
Math Instructions Video
   • BRX Do-More PLC Math Instructions  
Program Control
http://accautomation.ca/brx-plc-progr...
Program Control Video
   • BRX Do-More PLC Controller Program Co...  
Shifting Instructions
http://accautomation.ca/brx-plc-shift...
Shifting Instructions Video
   • BRX Do-More PLC Shifting Instructions  
Drum Instruction
http://accautomation.ca/brx-plc-drum-...
Drum Instruction Video
   • BRX Do-More PLC Drum Instruction Sequ...  

There are several reasons why we are using the BRX Series Controller. Here are just a few.
Standalone PLC with built in I/O
Built in Data Logging
Communication ability - Ethernet Port, RS232, RS485, USB - support for protocols such as Modbus RTU, Modbus TCP, ASCII, K-sequence (DirectLOGIC users), Custom Protocols (ASCII over serial, TCP or UDP over Ethernet)
Built in Analog input and output
Integrated motion control
High speed counters
Powerful instruction set (Video of Instructons in software)
Ability to expand the system with a variety of modules
Part of the Do-More series of PLCs which use the same free software. (Do-More Designer)
Integrated simulator in the software capable of external communications for testing

The BRX series of programmable logic controllers consist of four different units. They differ depending on the Inputs and Outputs built into the unit and if it has the ethernet port.
No I/O Micro PLC unit – (BX ME)
10 Point Micro PLC unit – (BX 10/10E)
18 Point Micro PLC unit - (BX 18/18E)
36 Point Micro PLC unit - (BX 36/36E)
These CPUs (Central Processing Units) are also known as MPU (Multi Processing Units) because of the communication capabilities.

http://www.accautomation.ca