SEN0657 Zero wind/rain
paulv 2026-01-21 18:39:48 940 Views4 Replies
I am using the SEN0657 Ultrasonic 7-in-1 RS485 weather station. Reading values seems to work fine.
My unit is currently inside and dry (so no wind or rain). I get the following values:
Wind Speed: 0.1
Wind Direction: 180
Rainfall: 0.2
I am trying to zero the wind/rain as described in the documentation. To zero rainfall I send:
0x1 0x6 0x60 0x2 0x0 0x5 0xf6 0x9
I then get the same string back as a response, which I guess means it was accepted:
0x1 0x6 0x60 0x2 0x0 0x5 0xf6 0x9
…but when I measure the values the Rainfall value is still 0.2
I have the same problem when trying to zero the wind value.
What am I doing wrong here?
Thanks,
Paul.
Hi paulv
What data frame are you using to query the rainfall data? I'm having trouble with that data.
After testing, and even after installation in the field with rain present, it's still showing a zero in the data frame.
Sometimes it registers, but other times it doesn't. In fact, during my tests, I can hear the sensor tilting as it rains, but the logs still show 0.
The command I'm using for accumulated rainfall is this:
0x01, 0x03, 0x02, 0x01, 0x00, 0x01, 0xD4, 0x72
Can you help me by confirming if it's the same command you're using, or if I'm using the wrong one?
Julian.Anaya Hi Julian,
Thanks for sharing the command and test details. Yes, 01 03 02 01 00 01 D4 72 is the correct command for reading the accumulated rainfall value.
Could you confirm whether your program resets the rainfall counter after each reading? For testing, please temporarily disable the reset command and let several rainfall events accumulate before checking the value again.
As Paul mentioned, during very light rainfall it may be better not to reset the counter when the returned value is 0.
Dear Customer,
Sorry for the inconvenience.
According to the register description in the product documentation, the Address code, Function code, and Register address you used look correct. For the “Modify value” part of the rainfall reset command, you may try writing 0x00 0x00 instead and test again.
In addition, the value of 0.2 you are reading may also be caused by sensor zero-point noise. It is recommended to test the sensor in different environments and observe whether the value changes.
You can refer to the register description in the Wiki here:
https://wiki.dfrobot.com/SKU_SEN0657_RS485_7in1_Weather_Station_Sensor#1.%20Basic%20communication%20parameters
If the issue still persists, please feel free to contact us at [email protected] with your test details, and our technical team will assist you further.
Best regards,
DFRobot Team
DFRobot TechSupport Thanks for your reply. I now have my unit installed outside where it regularly receives rainfall. I can confirm that writing 0x00 0x5A zeros the rainfall.
I am reading the rainfall every 30 minutes then zeroing the rainfall. I have found that if the rainfall value returned is zero it is better NOT to then zero the rainfall. It seems that very low rainfall will sometimes cause a zero reading but by zeroing the counters this very low value is lost. Changing the strategy to not zeroing the counters after a zero reading seems to give a better long term result.
