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Posts: 3
Registered: ‎09-11-2017
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when si7021 is needed to enable heat

I choose si7021 sensor to  Check environmental temperature and humidity .

It works  in a museum. These days I find the value of humidity is more than 93% and value of temperature  is about 20℃. There is no problem in temperater. 

 

Firstly, I replace a new device with sensor of si7021. And the value of humidity is between 78%-83% after 3 days.

 

I don't know why?

Shall I need to enable heater ? If so ,when I shuold to enable it.

 

our environment : temperature  20-25 ℃ ,humidity  65% - 75%

Posts: 67
Registered: ‎04-09-2015

Re: when si7021 is needed to enable heat

We recommend enabling the heater when the humidity readings are >80%. Depending on the heater setting this will drop the measured humidity rapidly - by 5% per C of heating. This means there should be some hysteresis until the heater is re-enabled.

 

Inaccurate readings can also result from contamination either in assembly or during use due to exposure to organic fumes such as paint and cleaning compounds.

Posts: 3
Registered: ‎09-11-2017

Re: when si7021 is needed to enable heat

Thanks for your reply!

The sensor is working in Isolation and it has been working for half a year. Last few months ,it works ok.

The value of humidity is always between 72% - 80%.

In recent weeks, the value of humidity rose 10%.I am sure that the environment is stable and the  inaccurate readings  result from contamination can be excluded.

By the way,the value of tempature is always right.

This is why?

 

As you said,it's recommended to enable the heater when the humidity readings are >80%.

How long shall we enable to heat ?  Shall we need to heat all the time?

If we enable to heat ,how I to get the values in a correct way?

 

our environment : temperature  20-25 ℃ ,humidity  65% - 75%

Posts: 3
Registered: ‎09-11-2017

how si7021 to do with heat

The sensor is working in Isolation and it has been working for half a year. Last few months ,it works ok.

The value of humidity is always between 72% - 80%.

In recent weeks, the value of humidity rose 10%.I am sure that the environment is stable and the  inaccurate readings  result from contamination can be excluded.

By the way,the value of tempature is always right.

This is why?

 

As you said,it's recommended to enable the heater when the humidity readings are >80%.

How long shall we enable to heat ?  Shall we need to heat all the time?

If we enable to heat ,how I to get the values in a correct way?

 

our environment : temperature  20-25 ℃ ,humidity  65% - 75%