Weird spec sheet - need help

Dasfgsadsa

Registered
I am trying to produce an uncertainty budget for my pH measurements.

The spec sheet for my transmitter can be seen here: See Link 1 (see under performance, temperature and transmission signals where repeatability, accuracy and linearity is stated).

Problem is, no where does the spec sheet say anything about whether this is a standard uncertainty or some sort of expanded uncertainty.

I have tried to Google my question with the following result: See link 2

"I am performing some uncertainty calculatons on my WT300E series power analyzer. Are these uncertainty specification at the 1-sigma (68%) or 2 sigma (95%)? I would assume 2-sigma but the datasheet doesn't explicitly state this so I would like confirmation.

ANSWER: The WT300 bulletin specifices accuracy, not uncertainty. The specification of accuracy is the 100% guaranteed value under the conditions specified in the data sheet, and if the error of the measured value exceeds the range of accuracy, the product will be the subject to repair. So, there is no implied statistical / distribution in our bulletin’s accuracy specification."

This is not for the transmitter I am using but for another product - however still a Yokogawa product. So it seems as if Yokogawa don't abide by the conventional way of stating uncertainty.

My question therefore is: How the heck do I use this information (from the quoted Q&A) and include it in my uncertainty budget?

Thanks
/David
 
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Dasfgsadsa

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Link1: web-material3.yokogawa.com/GS12A01F01-01EN.pdf
Link 2: tmi.yokogawa.com/us/library/resources/faqs/are-the-uncertainty-specifications-at-the-1-sigma-68-or-2-sigma-95/

Insert http:// yourself (since I am not allowed to)
 

dwperron

Trusted Information Resource
Nothing weird here.
They are expressing specifications for their devices, nowhere do they claim to be stating uncertainties.
To use specifications in an uncertainty budget you need to consider them as Type B contributors, and typically you will use a rectangular distribution to normalize the specification:

1638794826574.png
 

Dasfgsadsa

Registered
Nothing weird here.
They are expressing specifications for their devices, nowhere do they claim to be stating uncertainties.
To use specifications in an uncertainty budget you need to consider them as Type B contributors, and typically you will use a rectangular distribution to normalize the specification:

View attachment 28505
Great, thank you for your answer. That is exactly the information I initially implemented (from the M3003) before I started to question what I did. :)
 
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