Today, we will simulate and emulate, Modbus RTU Server (Master).
Imagine, we have a Modbus RTU device (PLC, Remote I/O, etc) connected to our PC through Serial (COM) Port.
then, let we change the device (hardware) with an application (software), we will simulate it. And also, let we change the COM port connection with virtual serial port.
Oke. we will use Mod_RSsim for the first one (Modbus RTU Simulator), and we will use VSPE (Virtual Serial Port Emulator) for the second one (Serial Port Emulator).
You can download Mod_RSsim from here.
You can download VSPE from here.
Oke. lets go..!
Now, we will configure the virtual connection of serial port :
- open VSPE application
- select Pair, then click Next
- select unused (undefined) Port, example COM3 and COM4, then Finish
- the Emulator has started
- dont close the application, minimize is Ok.
Now, we will open Mod_RSsim application as Modbus RTU Master simulator :
- open Mod_RSsim
- click on port icon to open the port setting
- select the type of I/O
- to write Digital Input or Coil Output, just double-click on the register
- to write Holding Register or Analog Input, double-click on register then write the value on the box
Oke. The next step is testing with Modbus RTU Client. We can use the simplest sample application from this blog: Modbus RTU Sample VB6.
Actually I develop new (advanced) sample project for Modbus RTU client, maybe I will post here someday.
Thats all.. Thanks for visiting..
See you next time.. :)