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SHT11 offset required?

 
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Requan



Joined: 11 May 2008
Posts: 74

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SHT11 offset required?
PostPosted: Mon Aug 13, 2012 2:17 am     Reply with quote
Hi,
I use SHT11 library from this forum (PIC16F690, ccs 4.134), so calculation function is:
Code:

void calculate_data (int16 temp, int16 humid, float & tc, float & rhlin, float & rhtrue)
{
float rh;

 //calculate temperature reading
 tc = ((float) temp * 0.01) - 40.0;

 //calculate Real RH reading
 rh = (float) humid;

 rhlin = (rh * 0.0405) - (rh * rh * 0.0000028) - 4.0;

 //calculate True RH reading
 rhtrue = ((tc - 25.0) * (0.01 + (0.00008 * rh))) + rhlin;
}

I compared temperature with two different thermometers and I saw that SHT11 has 2 degrees too many.
I read temperature each 10second.
Does that mean I will have to calibrate system with add offset?
Best Regards,
Martin
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Mon Aug 13, 2012 12:58 pm     Reply with quote
Quote:
I saw that SHT11 has 2 degrees too many.

Read this thread:
http://www.ccsinfo.com/forum/viewtopic.php?t=43073
Requan



Joined: 11 May 2008
Posts: 74

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PostPosted: Tue Aug 14, 2012 4:05 am     Reply with quote
Arrow PCM programmer
Thanks for Your reply. I read it previously but it didn't help me Sad
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