How to use "Online Simulation" with a serial device


In this post, we demonstrate how to use the “Online simulation” feature with a PLC or sensor that communicates using an RS-232 or RS-485 interface.
Note: This feature requires that you use a usb-serial cable supported by your PC’s OS.

Software Version:

EasyBuilder Pro


  1. Refer to the connection guide to verify that the communication driver supports “Online simulation”:
    Note: To find the PLC connection guide for the driver used within your project, please see this post: Link.

  2. Connect the usb-serial cable to your PC and open the “Device manager”:

  3. Locate the “USB-to-Serial” driver:

  4. Change the virtual COM port as need be by clicking the “Advanced” button:
    Note: The virtual COM port used below is COM6, but you may use any COM port between 4 - 9.

  5. Within EasyBuilder Pro, select a COM port that matches the COM port used by the adapter within the “Device manager”. Then, configure the COM settings according to the specifications of the connected device:

  6. When finished, click “Online simulation” to test communication.
    Note: In many cases it is necessary to use a null modem to connect the USB to serial adapter to the device. I prefer using one or more solderless DB9 connecters to match the pinout of the end device when possible.