Modbus POE ETH Relay
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Overview
Hardware Description
Hardware Connection
- Connects Modbus POE ETH Relay to the LAN via a network cable, powered through the power port or via POE.
Electrical Safety Precautions
- This product must be operated and used by professional electricians or technical personnel. During use, please ensure electrical safety and take measures to prevent leakage and insulation.
- Before installing, maintaining, or replacing relay equipment, be sure to turn off the power and unplug the plug.
- Do not attempt to disassemble relay equipment to avoid damaging the equipment or causing the risk of electric shock.
- Please install and place the relay equipment product properly. Do not use it in damp, overheated, or flammable environments to avoid safety incidents caused by improper installation or use.
Indicator Note
| Indicator | Status Description |
| RUN | Ethernet operation indicator. After the chip is working properly, it will output a square wave with a period of 2 seconds. |
| STA | MCU indicator, blinking when the MCU is operating normally. |
| TXD | Send indicator, light is on when sending data. |
| RXD | Receive indicator, light is on when receiving data. |
| Ethernet Port Green Light | The green light is on when a TCP connection is established and can be used to determine if the module has established a communication link with the host computer software. |
| Ethernet Port Yellow Light | Data transmission light, when there is data transmission on the network port, the yellow light transition state will change, which can be used to determine whether there is data transmission. |
Software Installation
Vircom can be used for configuring device IP and other parameters, as well as creating virtual serial ports. If the virtual serial port functionality is not needed, you can simply download the installation-free version of the configuration software.
- VirCom: Configuration Software
- Virtual serial port: Serial port driver
- Sscom5.13.1_for_Modbus_POE_ETH_Relay: Sscom software
Driver installation requires decompression, double-click the software to install, if the virtual serial port in Vircom is not displayed, then reboot and check again.
Example
TCP Communication Test
Software Preparation
- VirCom: Configuration Software
- Sscom5.13.1_for_Modbus_POE_ETH_Relay: Sscom software
Host Computer Setting
After connecting to the Modbus POE ETH Relay, connect it to the network. Run the Vircom software, (The computer on which Vircom is installed must be on the same LAN as the module.).
The operation is shown below:
- ① Click
Device - ② Click
Auto Search - ③ Software search recognizes Modbus POE ETH Relay devices connected to the LAN.
- ④ Select the device, and then click
Edit Deviceor directly double click the searched device. - ⑤ Set up the device parameters.
- Click the "Local IP" button to identify the computer's IP address, change the "IP Address" to a static address, and note that the static IP address entered is not used by other devices and needs to be on the same LAN as the computer.
- The operating mode is TCP server. The serial port setting defaults to 115200 and cannot be modified.
- The "Convert Protocol" in the
Advanced settings, the default setting is "None", that is, you select modbus rtu protocol. If you use Modbus_TCP protocol, you can select "modbus tcp protocol".
- Click the "Local IP" button to identify the computer's IP address, change the "IP Address" to a static address, and note that the static IP address entered is not used by other devices and needs to be on the same LAN as the computer.
- ⑥ After setting, click
Modify Setting. - ⑦ Click
Restart Dev. After restarting the module, the new setting takes effect.
As shown below:
The last step is to click "Modify Settings" to save the settings and take effect.
TCP Communication Test
- Open the serial debugging assistant window, select TCPClient for the port number, modify the remote IP and port number according to the above Vircom settings, click the "Connect" button to connect to the TCP server, the green light of the network port will light up after successful connection.
- Clicking on multiple strings will open multiple string-sending windows, and clicking on the corresponding functions will send the corresponding commands.
- Please refer to the development agreement for detailed Development Protocol.
Virtual Serial Port Testing
The SSCOM2 in the diagram communicates directly with the TCP and serial port server. In order to allow users to communicate with the serial port server using their existing serial port software, a virtual serial port needs to be added between the user program and the serial port server. As shown in the diagram, Vircom and the user program run on the same computer. Vircom virtualizes a COM port that corresponds to the serial port server. When the user program opens the COM communication, it can send data to the user's serial port device through the Vircom serial port server. The following steps demonstrate this operation:
Click on "Serial Port Management" on the Vircom main interface.
- Click on "Add" and select to add COM2. Note that COM5 is a COM port that does not exist on the computer originally.
- After that, go to the device management and double-click on the device that needs to be bound to COM2. As shown in the diagram, select COM2 from the "Virtual Serial Port" list in the top left corner. Then click on "Modify Settings" and then click on "Restart Device".
_Manual_103.png)
- Return to the main Vircom interface. You can see that COM2 is already connected to the device with IP 192.168.1.200. At this point, you can use COM2 to communicate instead of SSCOM2.
_Manual_104.png)
- Open it on your computer, open the corresponding port number, set the baud rate to 115200, click Multi-String to open the Multi-String Send window, and click the corresponding function to send the corresponding command.
MODBUS TCP Test
By default, data is transparently transmitted using the Modbus RTU protocol. If you need to implement Modbus TCP to RTU conversion, you need to select the conversion protocol as "Modbus TCP Protocol" in the device settings dialog, as shown in the diagram below. In this case, the device port automatically changes to 502. Users can connect their Modbus TCP tool to the IP of the serial port server on port 502, and the Modbus TCP commands they send will be converted to RTU commands and outputted through the serial port.
For example, if the server's Ethernet port receives a Modbus TCP command of 00 00 00 00 00 06 01 05 00 00 FF 00 (to turn on the first relay), the host controller will receive the Modbus RTU command of 01 05 00 00 FF 00 8C 3A.
_Manual_050.png)
- Click on "More advanced options..." Select the Modbus gateway type as a non-storage Modbus gateway.
Multi-host non-storage type.
- Open the Sscom software, click on the Import ini button in the Multiple String Sender column, and select the Modbus tcp.ini file to import.
If the error "A component named HEX0 already exists" is displayed, close the software and reopen it. Then close the software and reopen it, then re-import the file.
- After successful import, the following is displayed, click on the corresponding function to send the corresponding command.
- Please refer to the Modbus TCP protocol section later for more details on Modbus TCP conversion.
WEB Configuration
Using Vircom, you can search and configure device parameters in different network segments. For Web configuration, you must first ensure that the computer and the serial server are in the same IP segment, and you need to know the IP address of the serial server in advance. But web configuration can be done on any computer without Vircom.
1. Enter the IP address of the serial server in the browser, such as http://192.168.1.200
2. Enter a password in Password: There is no login password set by default in the factory, you can enter a password at will, and click the Login button to log in. After setting the password to log in, the settings at "Modify webpage login password" will take effect:
3. The serial server parameters can be modified on the web page that appears. For the relevant parameters, please refer to Table 4 for the meaning of the parameters.
4. After modifying the parameters, click the "Submit" button.
5. If the configuration web page files are overwritten during the configuration and downloading of MQTT and Jetson Modbus firmware, causing the configuration web page to be inaccessible, please follow these steps to re-download the web page files:
- Configuration Interface Web Files to Modbus POE ETH Relay.
Demo Example
Raspberry Pi
Connect the Raspberry Pi and the ModBus POE ETHG Relay module to the same LAN.
Open the Raspberry Pi terminal and run the program by entering the following command.
sudo apt-get install unzip wget https://files.waveshare.com/upload/e/e0/Modbus_POE_ETH_Relay_Code.zip unzip Modbus_POE_ETH_Relay_Code.zip cd Modbus_POE_ETH_Relay_Code #modbus rtu protocol vi modbus_rtu.py #Change the IP address and port number according to the actual situation sudo python3 modbus_rtu.py #modbus tcp protocol vi modbus_tcp.py #Change the IP address and port number according to the actual situation sudo python3 modbus_tcp.py
Modbus RTU Development Protocol
Function Code Introduction
| Function Code | Note |
|---|---|
| 01 | Read relay status |
| 03 | Read the address and version |
| 05 | Write a single relay |
| 06 | Set baud rate and address |
| 0F | Write all relays |
Single Relay Control
Sending Code: 01 05 00 00 FF 00 8C 3A
| Fields | Meaning | Remarks |
|---|---|---|
| 01 | Device Address | Fixed 0x01 |
| 05 | 05 Command | Control the relay command |
| 00 00 | Address | Control the register address of the relay, 0x00 - 0x0008 |
| FF 00 | Command | 0xFF00: relay on; 0x0000: relay off; 0x5500: relay flip |
| 8C 3A | CRC16 | CRC16 checksum of the first 6 bytes of data |
Return code: 01 05 00 00 FF 00 8C 3A
| Field | Meaning | Remarks |
|---|---|---|
| 01 | Device Address | Fixed 0x01 |
| 05 | 05 Command | Control the relay commands |
| 00 00 | Address | Control the register address of the relay: 0x0000-0x0008 |
| FF 00 | Command | 0xFF00: relay on; 0x0000: relay off; 0x5500: relay flip |
| 8C 3A | CRC16 | CRC16 checksum of the first 6 bytes of data |
For example:
CH1 relay on: 01 05 00 00 FF 00 8C 3A
CH1 relay off: 01 05 00 00 00 00 CD CA
CH2 relay on: 01 05 00 01 FF 00 DD FA
CH2 relay off: 01 05 00 01 00 00 9C 0A
CH3 relay on: 01 05 00 02 FF 00 2D FA
CH3 relay off: 01 05 00 02 00 00 6C 0A
CH4 relay on: 01 05 00 03 FF 00 7C 3A
CH4 relay off: 01 05 00 03 00 00 3D CA
CH1 relay flip: 01 05 00 00 55 00 F2 9A
CH2 relay flip: 01 05 00 01 55 00 A3 5A
CH3 relay flip: 01 05 00 02 55 00 53 5A
CH4 relay flip: 01 05 00 03 55 00 02 9A
Control All Relays
Sending code: 01 05 00 FF FF 00 BC 0A
| Fields | Meaning | Note |
|---|---|---|
| 01 | Device Address | Fixed 0x01 |
| 05 | 05 Command | Control relay commands |
| 00 FF | Address | Fixed 0x00FF |
| FF 00 | Command | 0xFF00: Relay on 0x0000: Relay off 0x5500: Relay flip |
| BC 0A | CRC16 | CRC16 checksum of the first 6 bytes of data |
Return code: 01 05 00 FF FF 00 BC 0A
| Fields | Meaning | Code |
|---|---|---|
| 01 | Device Address | Fixed 0x01 |
| 05 | 05 Command | Control the relay commands |
| 00 FF | Address | Fixed 0x00FF |
| FF 00 | Commands | 0xFF00: relay on 0x0000: relay off 0x5500: relay flip |
| BC 0A | CRC16 | CRC16 checksum of the first 6 bytes of data |
For example:
[No. 1 address device]:
All relays on: 01 05 00 FF FF 00 BC 0A
All relays off: 01 05 00 FF 00 00 FD FA
All relays flip: 01 05 00 FF 55 00 C2 AA
Read the Relay Status
Sending code: 01 01 00 00 00 08 3D CC
| Fields | Meaning | Note |
|---|---|---|
| 01 | Device address | Fixed 0x01 |
| 01 | 01 command | Query Relay Status Command |
| 00 00 | Relay start address | Fixed 0x0000 |
| 00 10 | Relay numbers | Fixed 0x0008 |
| 3D C6 | CRC16 | CRC16 checksum of the first 6 bytes of data |
Return code: 01 01 01 00 51 88
| Field | Meaning | Note |
|---|---|---|
| 01 | Device address | Fixed 0x01 |
| 01 | 01 command | Query Relay Status Command |
| 02 | Number of bytes | Returns all bytes of the status information |
| 00 | Status of the query | Returned relay status Bit0: the first relay status; Bit1: the second relay status; Bit2: the third relay status; …… Bit7: the 8th relay status. |
| 8C 35 | CRC16 | CRC16 checksum of the first 6 bytes of data |
For example:
Send: 01 01 00 00 00 08 3D CC
Return: 01 01 01 00 51 88 //All relays off
Send: 01 01 00 00 00 08 3D CC
Return: 01 01 01 01 90 48 //CH1 Relay is on, the rest of the relays are off.
Send: 01 01 00 00 00 08 3D CC
Return: 01 01 01 41 91 B8 //CH1 Relays and CH7 are on, the rest are off
Write Relay Status
Sending code: 01 0F 00 00 00 08 01 FF BE D5
| Field | Meaning | Note |
|---|---|---|
| 01 | Device Address | Fixed 0x01 |
| 0F | 0F Command | Write relay status command |
| 00 00 | Relay Start Address | Fixed 0x0000 |
| 00 08 | Relay Numbers | Fixed 0x0008 |
| 01 | Byte Count | Fixed 0x01 |
| FF | Relay status | Bit0: control the first relay; Bit1: control the second relay; Bit2: control the third relay; …… Bit7: control the 8th relay |
| BE D5 | CRC16 | CRC16 checksum of the first 6 bytes of data |
Return code: 01 0F 00 00 00 01 94 0B
| Field | Meaning | Note |
|---|---|---|
| 01 | Device Address | Fixed 0x01 |
| 0F | 0F Command | All register control commands |
| 00 00 | Address | Fixed 0x0000 |
| 00 08 | Relay Numbers | Fixed 0x0008 |
| 54 0D | CRC16 | CRC16 checksum of the first 6 bytes of data |
For example:
[No.1 address device]
All relays on: 01 0F 00 00 00 08 01 FF BE D5
All relays off: 01 0F 00 00 00 08 01 00 FE 95
CH1-2 ON; 4-8 OFF: 01 0F 00 00 00 08 01 03 BE 94
Relay Flash On and Flash Off Command
Sending code: 01 05 02 00 00 07 8D B0
| Field | Meaning | Note |
|---|---|---|
| 01 | Device Address | Fixed 0x01 |
| 05 | 05 Command | Single control demmand |
| 02 | Command | 02 is the command for flashing on, 04 is the command for flashing off |
| 00 | Relay Address | The address of the relay to be controlled: 0x00~0x08 |
| 00 07 | Interval Time | Delay time for data *100ms Value: 0x0007, Delay: 7*100MS = 700MS |
| 8D B0 | CRC16 | CRC16 checksum of the first 6 bytes of data |
Return code: 01 05 02 00 00 07 8D B0
| Field | Meaning | Note |
|---|---|---|
| 01 | Device Address | Fixed 0x01 |
| 05 | 05 Command | Single control command |
| 02 | Command | 02 is the command for flashing on, 04 is the command for flashing off |
| 00 | Relay Address | The address of the relay to be controlled: 0x00~0x08 |
| 00 07 | Interval Time | Delay time for data*100ms Value: 0x0007, delay: 7*100MS = 700MS |
| 8D B0 | CRC16 | CRC16 checksum of the first 6 bytes of data |
Note:
The maximum setting for the flash on/flash off time is 0x7FFF.
For example:
[No.1 address device]
CH1 Relay flashes on: 01 05 02 00 00 07 8D B0 //700MS = 7*100MS = 700MS
CH2 Relay flashes on: 01 05 02 01 00 08 9C 74 //800MS
CH1 Relay flashes off: 01 05 04 00 00 05 0C F9 //500MS
CH2 Relay flashes off: 01 05 04 01 00 06 1D 38 //600MS
Read the Device Address Command
Sending code: 00 03 40 00 00 01 90 1B
| Field | Meaning | Note |
|---|---|---|
| 00 | Device Address | Fixed 0x01 |
| 03 | 03 Command | Read the device address command |
| 40 00 | Command Register | 0x4000 is to read the device address, 0x8000 is to read the software version |
| 00 01 | Bytes Number | Fixed 0x0001 |
| 90 1B | CRC16 | CRC16 checksum of the first 6 bytes of data |
Return code: 01 03 02 00 01 79 84
| Field | Meaning | Note |
|---|---|---|
| 00 | Device Address | Fixed 0x01 |
| 03 | 03 Command | Read software version, read device address command |
| 02 | Byte Number | Return the number of bytes |
| 00 01 | Device Address | Set device address, fixed 0x01 |
| 79 84 | CRC16 | CRC16 checksum of the first 6 bytes of data |
For example:
Sending: 00 03 40 00 00 01 90 1B
Return: 01 03 02 00 01 79 84 //address 0x01
Read Software Version Command
Sending code: 00 03 80 00 00 01 AC 1B
| Field | Meaning | Note |
|---|---|---|
| 01 | Device Address | 0x00 indicates the broadcast address; 0x01-0xFF indicates the device address |
| 03 | 03 Command | Read software version, read device address command |
| 80 00 | Command Register | 0x4000 is to read the device address, 0x8000 is to read the software version |
| 00 01 | Byte Number | Fixed 0x0001 |
| 8F CA | CRC16 | CRC16 checksum of the first 6 bytes of data |
Return code: 01 03 02 00 64 B9 AF
| Field | Meaning | Note |
|---|---|---|
| 01 | Device Address | 0x00 indicates the broadcast address; 0x01-0xFF indicates the device address |
| 03 | 03 Command | Read the software version and the device address commands |
| 02 | Byte Number | Return code |
| 00 64 | Software Version | Convert to decimal and move the decimal point two places to the left to indicate the software version 0x0064 = 100 = V1.00 |
| B9 AF | CRC16 | CRC16 checksum of the first 6 bytes of data |
For example:
Sending: 00 03 80 00 00 01 AC 1B
Return: 01 03 02 00 64 B9 AF //0x0064 = 100 =V1.00
Modbus TCP Development Protocol
Here is a brief introduction to Modbus TCP and Modbus RTU protocol conversion using the above commands to open the first relay as an example.
- Modbus RTU command: 01 05 00 00 FF 00 8C 3A
| Field | Meaning | Note |
|---|---|---|
| 01 | Device Address | Fixed 0x01 |
| 05 | 05 Command | Control relay commands |
| 00 00 | Address | Address of the register to control the relay, 0x00, that is, the first relay |
| FF 00 | Command | 0xFF00: Relay on |
| 8C 3A | CRC16 | CRC16 checksum of the first 6 bytes of data |
- Modbus TCP command: 00 00 00 00 00 06 01 05 00 00 FF 00
| Field | Meaning | Note |
|---|---|---|
| 00 00 | Message Label | Both be 0x00 |
| 00 00 | Modbus Label | Must both be 0, which means this is Modbus communication |
| 00 06 | Byte Length | Indicates the number of all bytes that follow, followed by 6 bytes |
| 01 | Device Address | Fixed 0x01 |
| 05 | 05 Command | Control relay commands |
| 00 00 | Address | Address of the register to control the relay, 0x00, i.e. the first relay |
| FF 00 | Command | 0xFF00: relay on |
By comparing the commands above, we can observe that to convert a Modbus RTU command to Modbus TCP protocol, the CRC check is removed, and the command is prefixed with five 0x00 bytes followed by a byte representing the length.
Advanced Applications - MQTT Connected Cloud Platform
Software Preparation
Hardware Preparation
How to Connect
- Create an account access the platform using an email verification code, and then enter "Devices | Attributes" to create the device to operate after login.
- Viewing the device list, a new device appears:
- In the device menu, click to display the attributes section. Then, click on the "Address" button on the right to view the MQTT connection parameters. These parameters are preconfigured as part of the one-click setup, and the relevant attributes have already been created.
- The creation of the Waveshare Cloud device is now complete.
Configure Modbus POE ETH Relay with Vircom Software
- Plug in the device, connect it to the Ethernet cable, ensuring that the computer and the device are on the same local network, and then open Vircom to follow the instructions as shown in the diagram.
- Fill in the corresponding boxes with the parameters provided by Waveshare Cloud. Please note that errors may occur at this stage, and there may be related configuration files in the target directory. In this case, it is advisable to create a new empty directory and point to this empty directory.
- Confirm and then download the config.
- Afterward, click the "Refresh" button to search for the device. The device will automatically restart after updating the settings. At this point, you should see that the TCP Connection status is now 'Established.'
- Return to Waveshare Cloud to check the device status, which should now be in the "online" state.
- Access to the device is now complete.
Device Control
Dashboard Control
- Enter the Dashboard interface and select the corresponding device to develop.
- Controls the corresponding access switch buttons to perform operations:
Debug Online Test
Resource
Demo
Software
- Vircom
- Virtual serial port: Serial port driver
- Sscom5.13.1_for_Modbus_POE_ETH_Relay: SSCOM software
Related application
FAQ
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Support
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