DTU gateway connects to MQTT server, MQTT.fx tool test

4G DTU gateway connects to MQTT server + MQTT.fx tool debugging

Today, I will introduce how to configure the DTU gateway to connect to the MQTT server in a few simple steps, and then use the MQTT.fx client for serial port testing.

1. Equipment preparation

1. Hardware preparation

DTU gateway (ZL-LTE-300 ), SIM card, USB data cable, antenna, 485 to usb converter

2. Software preparation

DevelopLink_DTU1.0.9 host computer

MQTT.fx 1.7.1 host computer

2. DevelopLink_DTU host computer configuration

The DevelopLink_DTU host computer configuration is to solve the communication problem between DTU and MQTT server.

1.DevelopLink_DTU configuration

1. Select MQTT channel
2. Fill in the server address and port number, test server address: 115.159.225.58, port number 1883
3. Set account and password
4. Set DTU subscription and publish message topic
5. Select the theme to add IMEI, the best option is to ensure uniqueness
6. Click to write configuration, the device will automatically restart
7. It takes a few seconds to restart, and then read the configuration to see if the writing is successful. After the
   
   device restarts, wait a few seconds and observe that the DTU indicator Link indicator (green) is always on, then the MQTT server is connected.

2 FAQ

If the connection is not successful, check the following reasons:

• Whether to install the antenna, click to check the signal strength
  
• Whether to install a SIM card, or whether the SIM card has traffic, click to query the ICCID number
  

Three, MQTT.fx client debugging

MQTT.fx is the current mainstream mqtt client. It supports subscription and publishing of messages through Topic, which can quickly verify whether the device can communicate with the IoT cloud platform. The device sends the current state as an MQTT topic to the server, and the MQTT proxy server sends the received topic to all subscribed clients.

1.MQTT.fx configuration

1. home page
   
2. Connection configuration interface
   Click "Set configuration file" to edit the connection configuration.
   Change the MQTT server IP/domain name to the corresponding IP/domain name, here is: 115.159.225.58
   port number to the corresponding port number, here is: 1883
   click OK
   
3. Connect to the MQTT server
   Click the connect
   icon green, the MQTT.fx customer service terminal connects to the server successfully; if the icon is red, it fails, check the configuration
   
4. Subscribe to the corresponding topic
   Select subscribe to subscribe
   to the topic published by DTU: /device/pub/imei (imei is the only 15-digit number) and
   click subscribe to subscribe
   
5. Publish the corresponding topic
   Select publish to publish
   the topic subscribed by DTU: /device/sub/imei (imei is a unique 15-digit number)
   

Four, debugging

1. Basic preparation

DTU transmits and receives data through the 485 serial port, and connects to the computer through a 485-to-usb converter. The

default serial port parameters are shown in the figure.

2. Send message test

• DTU publishes messages to the (Broker) message broker server, and MQTT server publishes to the client.
  The operation is shown in the figure, you can see that the DTU 485 serial port successfully publishes data, and check whether the MQTT.fx client receives the subscribed message. The
  
  MQTT.fx client successfully receives the message
  

3. Receive message test

• The MQTT.fx client publishes messages to the (Broker) message broker server, and the MQTT server publishes to the DTU.
  MQTT.fx client publishes a message, check whether the DTU485 serial port has received the subscribed message,
  
  you can see that the DTU 485 serial port successfully received the data
  

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