@Stefan-de-Lange Thank you so much, it works now! My message appears at the IoT dashboard or T-Mobile.
The joke is that I bought these modules last Friday, and updating the modem seems very difficult. I would need to do that using a pass through AT+ command method. I will contact Arduino for that. Thanks a lot again! Bert

@Martijn-Kooijman Thanks for the advice! Good to know that current can be lower. I will check mine again. Other issues I had was missing messages, up to 20%! I seem to have solved it by adding a 4 s delay after opening a port (between opening port and sending message). I did that about 12 h ago and still not a single message lost!

@Crowdsourcer said in Arduino MKR NB1500: lukt niet om te verbinden.:

@Martijn-Kooijman @Stefan-de-Lange
Some news after the update (to 2.04): Lowpower.sleep (or deepSleep) has improved by a factor 2! The current reduced to 0.48 mA, still not very low power but at least an improvement.
The command AT+URAT=8 is not recognized anymore (comunication selection for NB only). It also seems that it sometimes needs a lot of time to open a channel after a deep_sleep (varies between 10 s and >30s which wastes energy).

I can confirm now that AT+URAT=8 works with the new firmware! Probably because I changed: AT+UMNOPROF=100 (European profile).

LiPo is fine (almost new 6000mAh)! I checked the schematics again and it appears that the 3.8V is produced from the LiPo by charge controller BQ24195. This 3.8V is then fed to the SARA modem and a LDO voltage regulator (AP2112) and converted to 3.3V. Seems that something is wrong with this converter, or its configuration?

Some follow up since last year: My MKR NB1500’s are all running on LiPo’s and the SARA modem is not transmitting any more at voltages below 3.8V. I looked up the schematics of this board and it appears that there is a 3V8 powerline for the SARA modem. However it is not produced anywhere on the board? The SARA modem power requirements state “typical 3.8V” so it could be that my SARA’s are a batch that does not like voltages even slightly lower than 3.8V? Seems like a bad board design? Anyone experiencing the same problems?

@Stefan-de-Lange
Yes, this is how it should work, and would save a lot of reconnection time, but so far I think >15mA is too much (reconnection time is about 20 s at around 60 mA on average).

@Crowdsourcer said in Arduino MKR NB1500: lukt niet om te verbinden.:

@Martijn-Kooijman @Stefan-de-Lange
Some news after the update (to 2.04): Lowpower.sleep (or deepSleep) has improved by a factor 2! The current reduced to 0.48 mA, still not very low power but at least an improvement.
The command AT+URAT=8 is not recognized anymore (comunication selection for NB only). It also seems that it sometimes needs a lot of time to open a channel after a deep_sleep (varies between 10 s and >30s which wastes energy).

I can confirm now that AT+URAT=8 works with the new firmware! Probably because I changed: AT+UMNOPROF=100 (European profile).

@Stefan-de-Lange
I tried AT+CPSMS=1 but the Arduino board consumed >15 mA during sleep. No idea why, but I think for the Arduino board it is easiest to just use the power_on pin (note that this is not the power supply pin!).

@Stefan-de-Lange
I just tested the SARA PSM setting:
Changed from default 0 to 4: AT+UPSV=4
After about 6 s inactivity it enters sleep mode and requires a dummy character to send to wake it up. I get reliable connection each time (using AT+USOCR=17,7000). So far so good,
however, sleep currents too high now (>10mA) and I also observe regular increases to >40 mA and accidental short drops <1 mA.
So it seems the SARA is consuming much more than your suggested 7uA during sleep time.

@Stefan-de-Lange
-The reset pin is used in the Arduino supplied SerialSARAPassthrough program so that seems fine to use for a reset.
-I did not test PSM, in default configuration it is off.
-I tested AT+UMNOPROF? and it is default 0, I then changed it to 100 (Standard Europe), but AT+URAT is still not available.
-For now after each wake up I do the following sequence (about 14 seconds in total):
AT+CFUN=0
AT+CEREG=3
AT+CFUN=1
wait for “CEREG:…” in a SARA response string
AT+COPS=1,2,“20416”
AT+USOCR=17,7000
check for USOCR: 0
then send data…

So far it seems to work fine.

@Stefan-de-Lange
Yes, still high, but there are more peripherals (such as the charger IC) so I think something like 50 uA should be expected.
Before sleep I do:
digitalWrite(SARA_PWR_ON, LOW); //to shut down the ublox

After sleep I need to switch on the modem and do a reset:
digitalWrite(SARA_PWR_ON, HIGH);
delay(100);
digitalWrite(SARA_RESETN, HIGH);
delay(100); //default 100
digitalWrite(SARA_RESETN, LOW);

I first wait about 10 s, then I open a port:
“AT+USOCR=17,7000”
I usually get an error: “+CME ERROR: Operation not allowed”
So I need to repeat this until I get:
+USOCR: 0
That usually takes between 12 and more than 40s.

Since URAT is not possible any more, it seems as if it has difficulty selecting NB?
Any recommendations to make this more reliable?

@Martijn-Kooijman @Stefan-de-Lange
Some news after the update (to 2.04): Lowpower.sleep (or deepSleep) has improved by a factor 2! The current reduced to 0.48 mA, still not very low power but at least an improvement.
The command AT+URAT=8 is not recognized anymore (comunication selection for NB only). It also seems that it sometimes needs a lot of time to open a channel after a deep_sleep (varies between 10 s and >30s which wastes energy).

@Martijn-Kooijman
This procedure was also recommended by Arduino. Exactly do as described by Zbelding: use Extra putty (his step 3). You can check if Extra putty works by entering an AT command such as ATI9, if all is fine the modem will return the current firmware. To be safe, just use Extra putty, it is a free download.
Did you wait the 21 minutes (step 18)?