Unable to receive from xbee

Q&A forumCategory: QuestionsUnable to receive from xbee
Daniel AAman asked 1 year ago
I am using two simpleRTK2B boards and two xbee modules that I have used in the past (i.e. not purchased from Ardusimple).

Running the xbees standalone works fine. I have them configured at 115200 and receiving and sending works fine.

The base setup, using the configuration file from this site works fine. I can verify in my other xbee that I am receiving the expected data. But when I plug the xbee into my rover configured board and I do not receive anything. I have enabled the monitoring for the ports and uart2 is 0. On the rover I can enable nmea as outgoing on uart2 and it will start transmitting on the xbee without any issues. But receiving is dead.

any ideas?

replied 1 year ago

You’ll perhaps need to get more specific about what XBee modules you’re using, and if they have any pin expectations/usage beyond those used by Digi, for whatever purposed. Things like flow control?

I’ve used some RAK811 break-outs in the past.

Daniel AAman
replied 1 year ago

I am using older XBee Digi pro 868Mhz radios and Funduino XBee USB adapters for connecting them to my laptop. I plug these in without any configuration and using 115200 8-N-1. As stated earlier sending works fine but I do not receive a single byte.

replied 1 year ago

The ZED-F9P has very simple requirements, the baud rates need to match Radio vs UART2, and the data needs to be moved transparently, no bytes added, none removed.
Totals perhaps via UBX-MON-COMMS, RTCM3 message reception/acceptance UBX-RXM-RTCM
Failing that you’re going to have to put a scope or logic analyzer on the signals.
Make sure the RX2/TX2 pins on the Arduino rail aren’t introducing noise or conflicting signals into the ZED-F9P

1 Answers
Ardusimple Staff answered 1 year ago
We can’t provide much support on 3rd party XBee Devices, each of them has its own peculiarities and not all are suitable for rtk. A few ideas to check:

  • Flow control must be disabled on the xbee device, zed-f9p doesn’t support flow control.
  • Your radios should have enough bandwidth for complete rtk corrections. Some xbee radios when they get buffer overflow they just stop the communication.
  • If you are using a programmable xbee device, check that rtcm is not containing an escape sequence that is setting your radio in command mode.
Daniel AAman
replied 1 year ago

I am receiving the RTCM3 messages fine when I plug my XBee into my laptop so that part is working. Does the board issue any AT commands when it initializes? I have an older XBee Digi pro 868Mhz radio.

replied 1 year ago

The ZED-F9P does not send AT commands to the radio, the radio needs to be preconfigured into the desired mode, and the ZED will communicated via UART2 (on standard un-switched designs) using the baud rate configured into the ZED.

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