nRF9160 DK's LTE not waking up from PSM

[isurki]

Hi!

I'm currently in the process of evaluating the nRF9160 DK. I'm trying to measure the current of the LTE when the PSM mode it's set. I'm using the at_client application and I am setting the PSM mode (using the LTE Link Monitor) like this:

AT+CPSMS=1,,,"00000001","00100001"

I can see the first active time just right after sending the at command, and it goes to PSM after a minute(like it should according to the parameters in the at command), but after 10 minutes it doesn't go back to active time.

Is there anything I'm missing?

thanks,

Ainara

[Håkon Alseth]

Hi Ainara,

 

The PSM TAU can be checked by sending the read command for CPSMS (see the AT commands pdf for more details):

AT+CPSMS?

 

This should then return the state and values set by the network.

Note that the network might provide you with another timeout value, as the device does not have the "final say" in this matter, it is the base station that sets this.

 

*edit*:

You should use "AT+CEREG?" to read the current state for PSM. AT+CPSMS? reads your requested PSM settings, while CEREG returns what the network has set.

 

Kind regards,

Håkon

[isurki]

Hi Håkon,

I already checked that and it returns the values I set before. I've checked The PSM TAU before setting any parameters and it returned 0. I've also configured the CPSMS with the default values (AT+CPSMS=) and checking it after that it returns 0.

I've changed the active time value and I see that it stays active according to the time I've set, however the TAU doesn't.

Kind regards,

Ainara

[Håkon Alseth]

Could you attach your log? I believe my former answer is incorrect, in that it returns your requested parameters, but not the parameters set by the network.

Could you read AT+CEREG? and see what that returns?

 

I will edit my initial answer to reflect this.

Kind regards,

Håkon

[isurki]

This is the log:

2019-05-29T06_51_12.627Z-log.txt

I read the AT command and it returns: 

+CEREG: 2,5,"434E","0C4BCA15",7

Kind regards,
Ainara

[Håkon Alseth]

Hi Ainara,

 

isurki said:

+CEREG: 2,5,"434E","0C4BCA15",7

The first number, 2, indicates:

2 – Enable unsolicited result codes +CEREG:<stat>[,<tac>,<ci>,<AcT>]

Here's the documentation for the cmd: https://infocenter.nordicsemi.com/index.jsp?topic=%2Fref_at_commands%2FREF%2Fat_commands%2Fnw_service%2Fcereg_read.html

 

If you in addition set:

AT+CEREG=5

 

This should provide more detailed info regarding PSM status.

 

Kind regards,

Håkon

[isurki]

Hi Håkon,

I've set AT+CEREG=5 and by reading the command I can see that both, the active timer and the TAU timer, are disabled. 

Thanks for the help. I guess using PSM timers is not the way to go for my application as I need to wake up the modem every 15 minutes. I will have to check that time in my running application.

Kind regards

Ainara