At command interaction function of the hottest DTU

At command interaction function of DTU module

sim900a has built-in at command, which is convenient for on-site technicians to use and debug GPRS module. After the module is powered on, the single chip microcomputer sends the capitalized "at" to make an i-call step of baud rate with the module. When the module responds, the i-call step is completed, and the user at this time. You can use at+ipr_ X set the baud rate and save the parameters. Once the baud rate is configured, the character "RDY" will be received from the serial port when the module is powered on again

1,) high or low voltage automatic shutdown

the module will continuously monitor the voltage on the Vbat. If the voltage is lower than 3.3 V, the serial port of the module will automatically send the following string:

undfr - voltage warning

if the voltage is higher than 4.7 V, the middle port of the module will automatically send the following characters:

0ver - voijage warnni friction coefficient and low noise ng

the limited voltage range is 3.2 ~ 4.8V. If the voltage is greater than 4.8 V or less than 3.2 V, the module will shut down automatically. After that, it will respond to the at command, and only RTC is active in the

shutdown mode

2) automatic shutdown at high or low temperature

the module has a temperature monitoring function. If the temperature is greater than 80 ℃, the middle port of the module will send the following characters:

+cmte:1

if the ambient temperature is less than - 30 ℃, the module will send the following characters:

+cmte: 1 l

the working temperature range of the module is from - 40 to +85 ℃. If the temperature exceeds this range, the module will automatically shut down immediately. Before the at command can be executed, you can make

use "at+cmte" to test the module temperature

3) establish TCP connection

in the sending characters of single chip microcomputer:

at+cipstart= "TCP", "27.1 51.9.1 51", 800 1

//set the IP address and port

OK

/module return value

connect OK

/TCP connection established successfully

at + cipend

00 010203040607080a ob OC od

0e of//send the address of the electric energy meter

send UK

4) establish a UPD connection

in the sending character:

at+ci assume that at this time, firmly bind pstart= "UDP, 27．1 5 1．9．1 5 1”、 8000

//set the IP address and port of the module

OK

//the experimental machine itself can measure the return value of the mobile gauge block with the prefix of 10

connect OK

//the connection is established successfully

at + FTP SF: nd

00 010203 0405080900a ob OC od

0e of

send OK

Alt + cipclose

//turn off UDP

5) establish transparent transmission mode

in the sending character:

at + cipmode = 1

/turn on the transparent mode

ok

at+cipstart= "TCP", "27.1 products of some foreign manufacturers 51.9.151", 800 1

ok

cinnect

//the connection is successful, and enter the transparent mode

ok

at+cipstart= "TCP", "27.1 51.9.151, ', 800 1

ok

cinnect

//the connection is successful, Enter the transparent mode

ok

//exit the transparent mode through DTR or++

Xi o

//return to the transparent mode through at0

connect

closed

//exit the transparent mode