PSM current consumption nRF9160

[Antoine]

Hello,

I'm working on getting PSM mode with the Serial LTE Modem on the nRF9160 v1.0.0. The power consumption of the modem (26.4 uA) is too high compared to the documentation in PSM (it should be 2.7 uA).

I juste used the file "nrf9160dk_serial_lte_modem_2022-02-17_ec486dab.hex" and "mfw_nrf9160_1.3.1.zip".

I send this commands :

AT+CPSMS=1,,,"10100011","00100001"

at#xsleep=2

I work with OTII :

I don't understand why the consumption is so high.

Also, I don't understand how to wake up the modem once it is in PSM. When I send commands via the UART after the command "at#xsleep=2", it does not respond.

Thank you for your help !

[Albrecht Markus Schellenberger]

Hello Antoine,

We are talking about to different things here:

• AT#XSLEEP is the SLM applications own implementation of going into idle or sleep mode. That does mean that if anything else than Idle mode is selected, the nRF9160 modem will be shut down.
• Power Saving Mode in LTE-M1 is a 3GPP standard. If configured, the nRF9160 modem will negotiate with the network for active time and tracking area update during connection establishment. However, that does not mean that the network will accept the values requested by the nRF9160 modem. In some cases, the network can reject the request completely, or assign different values. You can check the actual PSM settings by using e.g. AT%XMONITOR.

Also, I don't understand how to wake up the modem once it is in PSM. When I send commands via the UART after the command "at#xsleep=2", it does not respond.

As described here, you have to use the GPIO interface to wake up the application. The pin itself is defined via CONFIG_SLM_INTERFACE_PIN.

Regards,

Markus

[Antoine]

Hello Albrecht,

I already tried the PSM with another modem, the same SIM card and the same configuration and it worked.

The command AT%XMONITOR, gives :
%XMONITOR: 1,"Orange F","Orange F","20801","...",7,20,"...",483,6400,70,43,"","00011110","11100000","01001100"

When I just send the command to activate the PSM, the average consumption of the modem during the PSM is 1.47 mA. As shown in the picture, the communication does break down but the power consumption does not drop.


What value for CONFIG_SLM_INTERFACE_PIN should I set to wake up the modem via rts from the UART when I use the command "at#xsleep=2"?

Best regards,

Antoine

[Albrecht Markus Schellenberger]

Hello Antoine,

Antoine said:

When I just send the command to activate the PSM, the average consumption of the modem during the PSM is 1.47 mA. As shown in the picture, the communication does break down but the power consumption does not drop.

Is there any difference in power consumption when SLM is running normally and the modem is not in PSM vs after it has entered PSM? Are you using the UART0 or UART2 interface with the SLM?

Antoine said:

What value for CONFIG_SLM_INTERFACE_PIN should I set to wake up the modem via rts from the UART when I use the command "at#xsleep=2"?

The pin is configured to be triggered on a physical level low.

Regards,

Markus

[Antoine]

Hello,

Consumption when SLM is running normally and the modem is not in PSM : 24,1 uA

Consumption after it has entered PSM : 1.58 mA.

UART2 : I use the nRF9160 just to send AT commands.

I have the impression that it is because of the MK22FN128VLL10: the RTS doesn't work on the UART2, but that doesn't solve the PSM problem.

Best regards,

Antoine

[Albrecht Markus Schellenberger]

Thanks a lot for your feedback, Antoine!

Antoine said:

Consumption when SLM is running normally and the modem is not in PSM : 24,1 uA

Consumption after it has entered PSM : 1.58 mA.

This is indeed very strange and sounds close to not possible to be honest. Could you provide me with a full application log from boot of the nRF9160 until the modem enters PSM?

Thanks & regards,

//Markus

PS, FYI: Due to Easter vacation, our technical support team will be out of office from tomorrow on. You can expect a reply earliest Tuesday next week.