GSM SIM900 Time updating problem

[jagadeshreddy]

Hi,
we are reading time from GSM SIM900 RTC using CCLK commnad..we kkeep taking time and storing some sensor data with time stamp in a SD card.
The problem is time error..after 4:14, the hours becoming zero...
Can any one help ?

 

[hobbyckts]

One way to get current time is by sending a message to itself. Below is an example:


AT+CMGF=1
AT+CSCS="GSM"
AT+CMGS="0123456789" your phone number
THIS IS TEST test message
...
...
+CMTI: "SM",1 recevied a message at index:1
...
...
AT+CMGR=1
+CMGR: "REC UNREAD","0123456789","","14/11/15,15:03:13+22" got current time
THIS IS TEST


Sync your SIM900 with current time by
AT+CCLK="14/11/15,15:06:45+22"

 

[paulfjujo]

hello,


on my GSM2-click Quectel M95
i tried to get the Lan time to initialise the RTC when i start my program
.. (because RTC has no backup battery on this board)
and i use this quectel command

14:48:14.609>  Test si enregistré sur le reseau (AT+CREG?)
14:48:17.109> 
14:48:17.109> +CREG: 0,5
14:48:17.109> 
14:48:17.109> OK
14:48:17.109> 
[B]14:48:17.[/B]109> +QNITZ: "15/10/19,[B]12:47:30[/B]+08,0"
14:48:17.171>     Last Step:    3    
14:48:17.171>  Lecture de date et heure (AT+CCLK?)
14:48:19.671> 
14:48:19.671> +CCLK: "15/10/19,12:47:31+08"
14:48:19.671> 
14:48:19.671> OK

as you can see .. 2 hours shifted compare to my VBray terminal local time
but 08 => 8 x 1/4 heure => +2H00
so if i want to use it, i must add 8>>2 hours to the return time value ?
is it ?


when i use a SMS message back , i get the coorect HH:MM +08 ???

14:59:26.593>  Read message NON LUS (AT+CMGL="REC UNREAD")
14:59:30.156> +CMTI: "SM",1
[B]14:59:30.156>[/B] +CMGL: 1,"REC UNREAD","+336123456789","",[B]"2015/10/19 14:58:34+08"[/B]
14:59:30.156> Cde Led2 On
14:59:30.156> OK
14:59:30.250>  Retour d'ordre cde Leds 
14:59:30.250>  Contenu du SMS à envoyer
14:59:30.250> Retour Led1=0 Led2=1
14:59:30.250>  Compose Numero (AT+CMGS="+336123456789"
14:59:33.281> >  Pret pour envoi Msg txt 
14:59:37.343> +CMGS: 237
14:59:37.343> OK
14:59:37.343>  Envoi SMS OK :
14:59:37.343> Efface tous les SMS reçus (AT+QMGDA="DEL INBOX")
14:59:39.906> OK

 

[jagadeshreddy]

Thank you sir,
But when there is no network we will not receive the message immediately ,
So we are taking whenever network is there..but many times the time gets error exactly at 4:14

Thank you

 

[hobbyckts]

Are you working with single module? If possible try to read the time with different modules and let us know the result.

 

[BradtheRad]

error exactly at 4:14

4 times 60 = 240...

Add 14...

You get 254. Another increment or two, and then the value doesn't fit in one byte. Could this be the cause of the error?