Hello Support and Forum,
We are using BG600L-M3, set to LTE-M and GSM
(as described in PDF ‘BG95&BG77&BG600L Series Network Searching Scheme Introduction V2.0’) Our SIMs are from 1NCE.com (powered by Deutsche Telekom).
Normally this works excellent in all countries where LTE-M, GSM or both is available.
However, we recognised for a few devices (asset trackers) that they can (suddenly) not find any network any more, although definitely present in good level (and device not moved). We only allow search for a limited time (e.g. 60 seconds), to prevent wasting energy (e.g. if the tracker is on board of a ship or no net available). Normally network search only takes a few seconds, so I hope to be safe with 60 seconds. After data transfer the modem is powered off (with unregister) for periods, varying from 1h to 24h.
Why do these few devices not find network any more? Maybe a software problem on the modem or the SIM?
The above docu describes a sequence to reset some data in the modem:
// * If no net was found for more the 2 days: *
// Clear registration information history of the module
AT+QNVFD="/nv/item_files/modem/geran/grr/acq_db" // 1 GSM
AT+QNVFD="/nv/reg_files/modem/lte/rrc/csp/acq_db" // 2 LTE-M
AT+QNVFD="/nv/reg_files/modem/nb1/rrc/csp/acq_db" // 3 LTE-NB
// Clear xxLOCIs - Works only if 'cfun=1'
AT+CRSM=214,28542,0,0,11,"FFFFFFFFFFFFFFFFFFFFFF" // 4 OK Clear LOCI (RPLMN）
AT+CRSM=214,28531,0,0,14,"FFFFFFFFFFFFFFFFFFFFFFFFFFFF" // 5 OK Clear PLOCI
AT+CRSM=214,28643,0,0,18,"FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF" // 6 ERROR? Clear epsloci
// Search extra-long (240 sec)
search_time = 240;
The problem is very difficult to reproduce, so my questions:
1.) What are the reason for stalling?
2.) Might this sequence help?
3.) The last line does not work on BG600L-M3. Is this OK?
4.) Are there additional commands that could help?
5.) Is there a risk of flash-wear-out for the above sequence?
Thank you very much for your help!
Jo