485 TO ETH (B) User Manual
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Use the same baud rate as the device to open the serial port and send data "dev send",
and then see the returned data "dev send" in the receiving window. This is because we
publish the dev send message to the MQTT server under the subject of sub. But at the
same time our device is also subscribed to the topic sub, so the server will immediately
send us a subscription message, and the content of the subscription message is dev send.
This information is sent and downloaded as the MQTT payload, and is output from the serial
port through transparent transmission.
If other devices publish information, this device can also receive the data.
Generally speaking, users can directly transparently transmit serial port commands
(such as Modbus RTU) commands to the MQTT server. In addition, you can also use the
JSON function, using automatic Modbus RTU format collection, and regular JSON format
uploading. In addition, you can also find WAVESHARE to customize some non-standard
instruments and host computer protocol formats.
6. MQTT+JSON TO MODBUS RTU
Combining the above JSON and MQTT can achieve the following functions:
1. The MQTT-based protocol is used to establish a connection with the server, and data
communication is carried out in the form of subscription and publication.
2. Support independent design and automatic collection of Modbus RTU registers.
3. Support the conversion of specific Modbus register content into JSON format and send it
regularly and actively.
4. Support adding device ID to JSON format to facilitate cloud identification of devices.
If you need MQTT+JSON to Modbus RTU function, you can design MQTT and JSON
separately, in no particular order. Do not click the "Clear Design" button after designing one
type. After the two designs are finished, click the "Download" button together to download
the contents of the device.
Generally, you can manually restart the device after downloading to load the settings.
7. HTTP POST/GET+JSON
In addition to MQTT, the host computer protocol can also choose HTTP protocol, and
upload data through POST and GET instructions. Let's take the POST command as an
example to introduce.
If you need to support the POST/GET+JSON function, choose the Vircom
configuration tool to select version 5.17 and above; if you need to support POST command,
it needs to be version 5.81 and above (only If you support GETyou can use the ordinary
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