We will be installing a USB to rs485 installation on our computer. The CH340/CH341 USB to Serial port is a 2-wire USB to RS-485 serial communication adapter for RS485 use. It does not require an external power supply or complicated configuration.
It has a Type A (plug) USB connector for the computer side and screw terminals for the RS485 connections. The CH340/CH341 USB to serial device supports multiple baud rates and has a thumb drive design. Let’s get started installing our USB to RS485 adapter.
Purchase your USB to RS-485 serial adapter from the following affiliate links.
Installing the CH340/Ch341 Driver on PC
Do NOT connect the USB to RS-485 serial adapter to your PC before installing the driver file.
The CH340/CH341 USB to serial port Windows driver includes DLL dynamic library and non-standard baud rate settings and other instructions. It supports 32/64-bit Windows 10/8.1/8/7/VISTA/XP, Server 2016/2012/2008/2003, 2000/ME/98. The driver is Microsoft Certified and is USB 2.0 compliant.
Go to the following website and download the latest drivers for this device.
http://www.wch-ic.com/downloads/CH341SER_ZIP.html
The driver file is called CH341SER.ZIP
Download and extract the zip file. (Right-click on the zip file and select Extract All…. )
Open the extracted files and double-click on the Setup.exe file to install the driver.
The installation will automatically determine if you have a 32 or 64-bit computer. You will notice this on the setup window name. In my case, this is called DriverSetup(X64) because I am using a Windows 10 64-bit computer.
Select the INSTALL button.
This will now install the CH340 serial driver and then display a
message indicating that the installation was successful. Click OK.
USB Serial CH340 COM Port
Connect the USB to RS-485 serial adapter to your PC.
The computer will automatically detect this new device and use the driver that we installed above.
Call up the device manager and view the ports on your computer. The USB-SERIAL CH340 is on communication port 3. COM3 will now point to the USB port where the information is converted to an RS485 signal.
Note: The specific communication port (COM) used will depend on your computer system.
Right-click on the device and select properties.
You can see that our device has been set up and working properly. Select the port settings tab.
We can change the communication parameters from this tab like baud rate (Bits per Second), data bits, parity, and stop bits. Select the driver tab.
Information on the current driver installed for our USB to RS-485 serial adapter is displayed.
USB Serial Adapter Errors
If the USB to RS485 adapter was plugged into the computer before the driver was installed the following USB2.0-Ser! message will be shown under other devices in the device manager.
To correct this error, unplug the USB to Serial Adapter from the computer. Install the driver as outlined above. Insert the USB to RS485 Adapter into the computer. The device manager should now install the correct driver.
Watch the video below to see the installation of the USB to RS-485 serial adapter on a windows 10 64-bit computer.
Example of an RS485 network
We are now ready to connect to our equipment with the USB to RS485 converter. Since this is a serial device and is a 1: N connection. This means that we will have a master and at least one slave unit. The master is usually the PC (personal computer) that will control all communication. It will request information and receive answers. All communication must have the same parameters when communicating. What separates the communication is that each slave is assigned a unique number.
Example:
| Device | Computer ‘Master’ | Solo Process Controller ‘Slave’ |
Do-More PLC ‘Slave’ |
Additional Devices ‘Slaves’ |
| Station Address / Unit number | N/A | 1 | 2 | … |
| Baud Rate | 9600 | 9600 | 9600 | 9600 |
| Data Bits | 8 | 8 | 8 | 8 |
| Parity | Even | Even | Even | Even |
| Stop Bits | 1 | 1 | 1 | 1 |
The protocol is the actual communication (Information format that is transferred) that takes place over the network. (Master to Slaves) The media is the RS485 serial cable itself.
Node-RED Serial Modbus RTU Communication
Node-RED can be used to easily communicate as the Modbus Master on our serial network.
Monitoring the data we can view the values of our Solo temperature controller.
The Node-RED series can be viewed here to show you how to use this IoT enabling software.
Watch the video below to see the installation of the CH340/CH341 USB to Serial Adapter. Communication to the Solo process temperature controller using Node-RED serial RS485 Modbus RTU will be demonstrated.
Purchase your USB to RS-485 serial adapter from the following affiliate links.
Download the Node-RED flow program here.
Watch on YouTube: CH340 CH341 USB to Serial PC Installation
If you have any questions or need further information please contact me.
Thank you,
Garry
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