SHT71 temp/humidity sensor - accuracy issues
SHT71 temp/humidity sensor - accuracy issues
(OP)
I'm working on a project where I have a Sensirion SHT71 device tied to a PIC micro.
www.sensi rion.com/e n/sensors/ humidity/s ensors_dev ices/senso rSHT71.htm
I'm quite sure the code is working, thats not the issue at hand. If it wasn't then I wouldnt be getting semi valid, or sometimes valid data. Also, the device sends an ACK like I2C when it gets a valid command, and I get that...and I get return data.
What is the problem is getting accurate data. I'm looking for others that have used this part successfully, to find out if there are other things I am not doing right. Can you query it constantly? Or is there settle times? Just need to get some insight.
www.sensi
I'm quite sure the code is working, thats not the issue at hand. If it wasn't then I wouldnt be getting semi valid, or sometimes valid data. Also, the device sends an ACK like I2C when it gets a valid command, and I get that...and I get return data.
What is the problem is getting accurate data. I'm looking for others that have used this part successfully, to find out if there are other things I am not doing right. Can you query it constantly? Or is there settle times? Just need to get some insight.





RE: SHT71 temp/humidity sensor - accuracy issues
How are you interfacing with this device? Does your processor (PIC) have a special controller to talk this harware language, or are you doing it via software? If it is done through software, are you sure that it is correct?
Also, verify that the the unit is getting good, CLEAN power (both VDD and GND). Remember, ground bounce is just as bad as supply droop.
Finally, are you following the recommendations stated in 4.8 (don't run SCK and DATA parallel for more than 10cm, to prevent cross-talk)?
RE: SHT71 temp/humidity sensor - accuracy issues
But, did give me an idea to run the clock and data above board just to make sure it isn't crosstalk. Generally running at slow speeds, crosstalk isnt an issue. And it isn't the fact the data is garbage, its like 5degrees off where it should be.