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GPS and CR1000X

koxme Apr 24, 2019 01:43 PM

Hi there,

We just connected a couple of different GPS to a CR1000X and the time is not being changed when the difference is bigger than 100ms. Neither it changes when connected to a CR1000.

The PPS level is 3V for these GPS

In the GPS instruction the COM1 port is set as negative

Any suggestion?


PS: for the CR1000 the instruction to set the baud rate is: SetStatus("baudRateCOM1", 9600) but the CR1000X does not recognize it, I tried with ComC1 and similars, but no way, how can I set the baud rate for a Com port in the code for a CR1000X?

koxme Apr 24, 2019 02:02 PM

Forgot to say, the readings of the GPS are correct

GaryTRoberts Apr 24, 2019 02:16 PM

In order to change the time, the GPS needs to stream the $GPRMC sentence. You can check to see what strings are being outputted by watching the GPS port in the terminal.

koxme Apr 24, 2019 02:51 PM

Hi gary,

thanks for your answer.

yes, I can see the GPRMC sentence in theterminal emulator:

16:47:12.191 R 8,,240419,,,A*6B

replaced actual coordinates with 9999, but it seems to be fine, doesn´t it?

GaryTRoberts Apr 24, 2019 03:05 PM

Also, reading the help for the GPS instruction the $GPGGA string must be there as well. Is that one coming though as well?

koxme Apr 25, 2019 06:29 AM


Thanks Gary,

yes, the $GPGGA string is there too

16:47:13.299 R 7,1.32,444.8,M,49.7,M,,*45

I checked the PPS pulse with the tester and it is OK, so I guess there is something wrong with the code¿?

The instruction is simple, I don´t really know where to keep searching

Scan (1,Sec,0,0)

GPS (gps_data(),-ComC1,3600,100,nmea_sentence(2))

Italo Apr 25, 2019 01:48 PM

To set Com port baudrate in the code you need to use SetSetting function.


This info can be found in the help file of CR1000X, the path is Campbellsci\Lib\CRBasicDefFiles\Crbasic1x.chm

Search for setsetting and it will have infos about a lot of things that you can set in the code.

koxme Apr 26, 2019 07:15 AM

Thanks, Italo!

koxme May 8, 2019 09:21 AM

Any other suggestion for the GPS time sync?


leoramos Nov 29, 2020 02:16 PM

I also have this problem. I have one gps16x LVS. but is not changing the datalogger time and I have the two strings as well (gogga and gprmc) 

I also configured the gps to push just those two strings and the baudrate about 38.4k. 

Nicolas Jun 12, 2021 03:40 PM


I'm trying to establish communication between a CR300 (new and last OS update) and a GPS (NMEA 0183 V3.01: GGA, GSA, GSV, RMC, VTG - 9600 bps) with this simple code.:


   Scan (1,Sec,0,0)     

   GPS (latitude_a,COMC1_RX,C2,LOCAL_TIME_OFFSET*3600,100,nmea_sentence(1),9600)    

As you can imagine, it doesn't work (tested with or without a PPS signal), I get NAN for all the frames coming from the GPS.

On the oscilloscope, I have a PPS signal of 3.3 V at 1 Hz as well as the data frame from the GPS (@ 5V). The data frame is approximately 910ms (always less than 1000ms).

The PPS parameter always return approx. 550 ms (that it is transmitted on C2, SE1, ...)), i don't understand.

On the terminal (7: COM RX), I have no data

I don't know what to test anymore. Please, do you have an idea ?

Thank you,


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