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# How to calculate temperature coefficient

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#### hemnath

Hi,
I have a pressure calibrator and I opened to check the sensor. It is Meas sensor 89CV.

On the sensor datasheet, its temperature data's are,
Temperature Error – Span -1.0 %Span
Temperature Error – Zero - 1.0 %Span
Thermal Hysteresis – Span ±0.05 %Span
Thermal Hysteresis – Zero ±0.05 %Span
Compensated Temperature Range -20 +85 ºC

But in their product datsheet, it is mentioned as,
Temperature coefficient ± 0.005% of reading / °C with respect to 20°C
Operating Temperature 0 to 50°C
Calibrated Temperature 20°C ± 2°C
Calibrated Temp. Range 0 to 50°C
Storage Temperature -20 to 70°C
Temperature Effects 0.001% of reading /°C between 0 to 50°C

When I try to calculate using sensor datasheet,
1%span = -20 +85 ºC
1% span = 105ºC
1 ºC = 1%span/105
1 ºC = 0.009% span
Is this calculation is correct for calculating temperature coefficient?

Could you please explain how to calculate temperature coefficient and temperature effects?

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#### KlausST

##### Super Moderator
Staff member
Hi,

Span: -20°C ... 85°C = 105°C
So 1% span = 1% × 105°C = 0.01 x 105°C = 1.05°C

Klaus

#### hemnath

Thanks for your reply. The point is not clear for me. Sorry.

#### d123

Hi,

Not sure if tempco method valid for this...
+-0.005%/°C might mean that moving away from 20°C ambient or device junction temperature it adds the ppm (tempco) error.
+-0.005 * (50°C - 20°C) = +-0.15
1 - 0.15 = 0.85, 0.85 * 50°C = 42.5
1 + 0.15 = 1.15, 1.15 * 50°C = 57.5

Or maybe under 20°C it is -0.005% per °C and over 20°C the error is +0.005% per °C.

Not sure, I could be completely wrong. Datasheet might have a box method graph to show expected error curve or 's' shape across temperature range under their test conditions.
--- Updated ---

Datasheet would help a lot.

#### Akanimo

Hi,
Hi,
I have a pressure calibrator and I opened to check the sensor. It is Meas sensor 89CV.

On the sensor datasheet, its temperature data's are, ...
🧐
But in their product datsheet, it is mentioned as,
When I try to calculate using sensor datasheet, Is this calculation is correct for calculating temperature coefficient?

Could you please explain how to calculate temperature coefficient and temperature effects?
I would be expecting some pressure numbers here though.

#### dick_freebird

What the tempco -is-, and what the tempco
"could be and still get shipped" are loosely related.
The latter pertains to WCA but isn't going to tell
you anything about one piece in hand necessarily.
Other than, it should be better (how much, is not
said unless you paid for detailed test data pack
which is not really an option outside MIL / aerospace
product grades with their heinous pricing, to which
the data pack is always another lot based upcharge).

Some sensors have nonlinearity (bowing) which
will make an end-end tempco lower than tempco
measured near either end and higher than in the
middle.

#### Akanimo

What do you want to do - to determine the adjusted pressure from representative measured voltage?

Actually, the sensor is already partially compensated for temperature effects.

#### Akanimo

To be able to obtain temperature coefficients, both of zero and of span, you would need to have measured voltage data for both minimum and maximum pressures at maximum temperature Tmax, assuming that those presented in the datasheet would be for ambient temperature.

#### Akanimo

For the sake of one that might reference this thread in future:

...assuming that those presented in the datasheet would be for ambient temperature.
By this I meant 'if you thought that those presented in the datasheet were for ambient temperature'.

Unfortunately, I am not a native English speaker.

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