+QOPS stops working on EG91-NAXD

IoT Modules LTE Standard Module
1

Hi,

The band-scan feature (+QOPS) is great, but I’m experiencing a problem sometimes.

I use this sequence of commands to request a band scan:

  1. I check attached/detached status of EG91:

      AT+CGATT?

If the response indicates ATTACHED (1) then I send this command to DETACH:

      AT+CGATT=0

  1. Here are the commands and response to invoke the band scan:

    send: AT+QCFG=“nwscanmode”
    response: +QCFG: “nwscanmode”,0

    send: AT+QOPSCFG=“scancontrol”
    response: QOPSCFG: “scancontrol”,3,0xffffffffbfffffff,0x7ffffdf3fff,0x3f

    send: AT+QOPS
    response: '+QOPS: “Verizon”,“Verizon”,“311480”
    1,“4G”,5230,265,1904,63C502,-84,-13,0
    2,“4G”,2600,66,1904,63C110,-111,-17,0
    +QOPS: “AT&T”,“AT&T”,“310410”
    1,“4G”,5110,471,8104,72CCE10,-95,-16,0
    2,“4G”,1100,276,8104,72CDF09,-112,-13,0
    3,“4G”,2000,337,8104,72CC017,-114,-19,0
    4,“4G”,2250,337,8104,72CC0CA,-117,-19,0
    +QOPS: “”,“”,“313100”
    1,“4G”,5110,471,8104,72CCE10,-95,-16,0
    2,“4G”,1100,276,8104,72CDF09,-112,-13,0
    3,“4G”,2000,337,8104,72CC017,-114,-19,0
    4,“4G”,2250,337,8104,72CC0CA,-117,-19,0
    +QOPS: “T-Mobile”,“T-Mobile”,“310260”
    1,“4G”,650,192,291F,15B9A0B,-102,-15,0
    2,“4G”,2350,192,291F,15B9A01,-103,-15,0
    OK
    The band scan works.

I can repeat the band scan, again and again, for hours at a time, and it continues to work. For example, I did more than 10,000 band scans, pausing for a couple of seconds between scans, and it worked without any problem.

However, if I wait for a while (at least a few minutes) after a band scan and then request a band scan, in exactly the same way, I don’t get any errors, but the response to,

      AT+QOPS

is only:

      OK

Once that happens, it continues to happen every time I request a band scan. If I cycle the power then I can get a proper band scan, until I let enough time pass between band scans.

This problem is consistent. I can’t tell you exactly how long I must wait between band scans to see the problem, but I can say that if I wait 5 minutes between band scans the next band scan may give valid data or may just return OK.

I’ll be most grateful for advice and/or suggestions.

Regards,
Matt

2

hi，
Please note the following when using this command:

image
image876×215 28 KB

3

Please read my original post carefully. I believe I have not violated any of the guidelines in the Notes you referred me to.

-Matt

4

hi，
Can you provide the corresponding Souwang log? In this way, you can see how the band is scanned and the network search mechanism. and the firmware version of the current module.

5

Hi AnnaLiu,

Thank your for your assistance. I am most grateful.

I will be pleased to provide the “Souwang log,” but I do not know how to produce it. Can you share instructions with me for producing the log. I connect the EG91 to a custom device (which I manufacture) which runs Linux.

Thank you,

Matt
mbrenner@unme2.com

6

hi，
Tools and documentation I have sent via email.
Grab the log of cfun 0,1
Then reproduce your problem
Just export the log

7

hi ,
Please use AT+QGMR to check the current version