Mavros signals endless "PR: got an unsolicited param value"

Hello, I am using - MAVROS V1.5.0 installed as per the official README - ROS Melodic - Ubuntu Bionic - Original Pixhawk 2.4.8 with ArduRover 4.0.0

I connect to the Pixhawk via USB (dev/ttyACM1 115200 Baud) Establish connection to FCU and subscribe to a small set of messages like State, GPS_RAW etc. There is no code that would alter or call for Parameters.

However after about a minute I get an endless supply of "PR: got an unsolicited param value" for different param id's. I would understand this when using the bridge to connect a GCS via Mavros but this is not the case here.

Has anyone experienced this before? Or does anyone know where these might come from and how to fix ist.

Thanks for your help

UPDATE: I after having it run some time I checked the LOG: apparently Mavros is requesting the parameters initially but at some point one is not received in the expected time. So the request stops even if the remaining 631 have not arrived yet But they are received later and since the timeout has run out they are not requested.

1612283889.021178651 PR: request param #308 timeout, retries left 2, and 631 params still missing 1612283889.141140835 PR: got an unsolicited param value idx=308, not resetting retries count 3 1612283889.143357560 PR: got an unsolicited param value idx=309, not resetting retries count 3 1612283889.145959552 PR: got an unsolicited param value idx=310, not resetting retries count 3

So since there seem to be no further retries, I would say I need to check the code and if necessary check with the developer

Sorry for spamming the forum

Asked by monkfood on 2021-02-02 21:40:36 UTC

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Answers

Hi, I am using MAVROS installed as the official ROS Melodic version and a Pixhawk with ArduCopter 4.0.5.

I connect to the Pixhawk via /dev/ttyTHS1, 1500000 Baud. The connection between the FCU and MavROS seems to be established and some features appear in the MavROS window (as the frame type), but after few seconds the same problem as you happens: an endless supply of "PR: got an unsolicited param value" for different param id's.

Have you got a solution to fix it? Does anyone know the potential source of this error?

Thanks for your help

Asked by Sissi on 2021-03-17 05:19:04 UTC

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Hi Sissi, I found that the problem was mainly at the beginning when forwarding of the Parameters to the GSC which i guess requests the them via mavros. I set the baud rate of the PIX and my app to 115200. That was sufficient. The error occured only at the beginning. As far as i remember i looked at the code and the timeout for the parameter response is high enough but if I did not missread the code, it seems also that the watchdog counter has a small bug. It does not count but respons unsolicited after the first try.

Check if the problem is continuous or only at the beginning, meaning check if idx=xxx is counting up and stops when all parameters have been read once.

Asked by monkfood on 2021-03-21 23:55:55 UTC