Chengdu Ebyte Electronic Technology Co.,Ltd E840-TTL(4G-02)User Manual
Copyright
©
2012
–
2019
，
Chengdu Ebyte Electronic Technology Co.,Ltd
18
5. Modbus RTU and Modbus TCP are mutually converted;
E840-TTL-(4G-02) supports the mutual conversion between Modbus RTU and ModbusTCP. After the function is enabled, after
receiving the data, the device will detect whether the data meets the Modbus RTU or ModbusTCP protocol. If it meets the
requirement, the conversion function is enabled. Otherwise, it will output/send original data.
a) For example, the serial port receives the ModbusT RTU write-out command in the following format (hexadecimal):
01 06 00 01 00 01 19 CA (ModbusT RTU), when the conversion function is enabled, the data received by the server is: 00 00 00
00 00 06 01 06 00 01 00 01 (ModbusT TCP)
b) When the data received by the network is: 00 00 00 00 00 06 01 06 00 01 00 01 (ModbusT TCP), the serial port of the device will
output the data : 01 06 00 01 00 01 19 CA (ModbusT RTU);
Note: In the Modbus TCP standard protocol, the transaction element identifier needs to be specified. In E840-TTL-(4G-02), the
user can configure the value through AT+MTCPID, and when the value is configured to 0, the receiving end All data
conforming to the Modbus TCP protocol will be parsed, otherwise only packets with the same application packet identifier and
device configuration identifier will be converted.
6 Base station positioning function;
The E840-TTL-(4G-02) supports the base station positioning function. The user can send the AT+LBS command in the AT mode
to read the current LBS information of the device. The device returns the data format as follows:
+OK=LAC,xxxx;CID,xxxx, where LAC is the unique identification number of the global cell, CID is the base station number,
(xxxx is the hexadecimal value);
The LAC and CID number can be used to query the current location information of the device. For the query method, refer to the
link: http://www.gpsspg.com/bs.htm
7 Serial port packaging function;
The E840-TTL-(4G-02) serial port break time and packing length can be configured. The user can configure the frame break
time and the package length through the AT+UARTTS command. Please refers to the AT command for the specific configuration .
a) Frame break time: When the serial port receives data, it will continuously detect the interval between two bytes. If it is greater
than the configuration time (50-2000ms), the device will automatically send the previously received data as a data packet to Network
side;
b) Packing length: When the serial port receives data, it will continuously check the length of the currently received data. If the
