KPY 12 - A PRESSURE TRANSDUCER SUITABLE FOR LOW TEMPERATURE USE

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Submitted on 1 Jan 1984

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KPY 12 - A PRESSURE TRANSDUCER SUITABLE FOR LOW TEMPERATURE USE

F. Breimesser, L. Intichar, M. Poppinger, C. Schnapper

To cite this version:

F. Breimesser, L. Intichar, M. Poppinger, C. Schnapper. KPY 12 - A PRESSURE TRANSDUCER

SUITABLE FOR LOW TEMPERATURE USE. Journal de Physique Colloques, 1984, 45 (C1), pp.C1-

671-C1-674. �10.1051/jphyscol:19841136�. �jpa-00223607�

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KPY 1 2

-

A PRESSURE TRANSDUCER S U I T A B L E FOR LOW TEMPERATURE USE

F . Breimesser, L . Intichar, M . Poppinger and C . Schnapper

Siemens AG, Research Laboratories, Paul Gossen S t r . 100, 0-8520 ErZangen, F.R.G.

R6sum6: Le capteur de pression K P Y 12 commercialis6 par Siemens permet de mesurer des diff6rence.s de pression jusqul$ 2 bars dans la plage de temp6rature de 243 K 5 298 K.

A des tempbratures tr&s basses atteiqnant 4 K , la lin6arit6 est conservge et la sensibilith sSaccroZt de 100 % environ. Le capteur a kt6 utilis6 avec succes 2 basse temp6rature dans une installation d'essai fonctionnant 2 3000 tr/min.

Abstract: The commercially available Siemens pressure sensor K P Y 12 in silicon planar technology measures differential pressures up to 2 bar in the temperature range from 243 K to 398 K . However, at temperatures down to 4 K the specified linearity is also preserved, and the sensitivity increases by about 100 %. The sensor has been successfully em- ployed at low temperatures in a test rig rotating at 3000 rpm.

Description of the K P Y 12

The pressure deflects a silicon plate, setting up strains in silicon resistors located on top of the plate. The strains are converted into an electrical signal by the piezoresistive effect.

As is usual with strain gages, four resistors are arranged in a Wheat- stone bridge. The pressure load causes a decrease in the resistance of two resistors and an lncrease in the resistance of the other two resistors. The chip of the K P Y 12 is shown in Figure 1 . It is mounted in a TO-8-like encapsulation (Figure 2 ) . The specifications of the KPY 12 are summarized in Table 1 .

Table 1 :

Specifications of K P Y I 2- pressure transducer

Operating temperature -30 to 125 " C

Bridge resistance s 7

kR

Full scale output 1 0 +

-

³ ^{mV/V bar}

Zero balance

_- +

⁵ ^mV/V

~ i n e a r i t ~ l )

+

^0.5 % FS Thermal sensitivity shift 1 0.2 typ- %/K Thermal zero shift _-+ 0.02 % / K FS Hysteresis < 0.5 % FS

Response time

<

¹ ^ms

Weight % 2.7 9

1) maximum deviation from best straight line fit vs full scale output.

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19841136

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JOURNAL DE _PHYSIQUE

F i q . 1 :

P r e s s u r e s e n s o r c h i p - s i z e 4 x 4 m m 2

F i g . 2 : K P Y I 2 s e n s o r

Low t e m p e r a t u r e e x p e r i m e n t s

The b r i d g e v o l t a g e , U , a n d t h e s u p p l y c u r r e n t , I s , of s e v e r a l

s e n s o r s w e r e m e a s u r e d a s a f u n c t i o n of p r e s s u r e , p , a n d t e m p e r a t u r e , T . The s u p p l y v o l t a g e was U = 5 V .

F i g . 3 shows some t r a n s d u c e r c h a r a c t e r i s t i c s o f o n e s e n - s o r . A t a l l t e m p e r a t u r e s , t h e l i n e a r i t y i s a s good a s s p e - c i f i e d a t room t e m p e r a t u r e . The s e n s i t i v i t y s = ( U - U o ) / p i n c r e a s e s w i t h d e c r e a s i n g t e m - p e r a t u r e .

F i g . 3 :

T y p i c a l o u t p u t v o l t a g e v e r s u s p r e s s u r e f o r a K P Y 1 2 s e n s q r a t d i f f e r - e n t t e m p e r a t u r e s

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The o f f s e t v o l t a g e , U , i s s e n s o r - s p e c i f i c a n d d e p e n d s s l i g h t l y o n t e m p e r a t u r e . I n F i g .

8 ,

t h e n o r m a l i z e d s e n s i t i v i t y s ( T ) / s ( T = 2 9 3 K ) and t h e o f f s e t v o l t a g e U

o ( T ) o f a s e n s o r a r e p l o t t e d a g a i n s t t e m p e r a t u r e .

Due t o t h e s p e c i f i e d t o l e r a n c e s t h e i n d i v i d u a l s e n s o r h a s t o b e c a l i - b r a t e d f o r a p r e c i s e p r e s s u r e m e a s u r e m e n t . I n a d d i t i o n , t h e o p e r a t i n g t e m p e r a t u r e m u s t b e known. F o r r e d u c e d p r e c i s i o n r e q u i r e m e n t s i n t e r - p o l a t i o n b a s e d on t h r e e r e f e r e n c e m e a s u r e m e n t s a t 4 K, 77 K a n d room t e m p e r a t u r e may b e s u f f i c i e n t .

A t t e m p e r a t u r e s b e l o w 90 K a n d a b o v e 220 K t h e t e m p e r a t u r e c a n b e d e t e r m i n e d f r o m t h e b r i d g e r e s i s t a n c e Rb5 = U s / I s . I t i s a l m o s t i n d e - p e n d e n t o f p r e s s u r e ( d ( L \ R / R ) / d p h 6 . 1 0 - b a r - 1 ) b u t i t d e p e n d s o n t e m p e r a t u r e . F i g - 5 s h o w s t h e r a t i o R b r ( T ) / R b r ( T = 293 against t e m p e r a t u r e . The t e m p e r a t u r e d e p e n d e n c e was a l m o s t i d e n t i c a l f o r t h e s e n s o r s i n v e s t i g a t e d .

t e m p e r a t u r e

F i g . 4 :

N o r m a l i z e d s e n s i t i v i t y a n d o f f s e t v o l t a g e a g a i n s t t e m p e r a t u r e

t e m p e r a t u r e

F i g . 5 :

N o r m a l i z e d b r i d q e r e s i s t a n c e a g a i n s t t e m p e r a t u r e

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JOURNAL DE PHYSIQUE

A p p l i c a t i o n

F o r t e s t i n g a c o o l i n g s y s t e m , t h e p r e s s u r e o f c o l d h e l i u m g a s h a s t o b e m e a s u r e d d i r e c t l y i n a c o n t a i n e r r o t a t i n g a t 3 0 0 0 r p m . T h e s e n s o r K P Y 1 2 w a s c h o s e n , b e c a u s e i t i s s m a l l , h i g h - v a c u u m t i q h t , w i t h s t a n d s h i g h m e c h a n i c a l l o a d s a n d h a s l i t t l e t h e r m a l l o a d ( t y p i c a l l y 5 mW a t U = 5 V ) . F o r m o r e t h a n o n e y e a r t h e s e n s o r h a s w o r k e d r e l i a b l y a n d w ? t h o u t p r o b l e m s .

S e n s o r s o f t h i s t y p e o f f e r t h e p o s s i b i l i t y o f m e a s u r i n g n o t o n l y t h e p r e s s u r e , b u t a l s o d e r i v e d q u a n t i t i e s , e . g . f l o w r a t e s ( b y m e a s u r i n g o r i f i c e s ) o r l i q u i d l e v e l s a t c r y o g e n i c t e m p e r a t u r e s .

A c k n o w l e d g e m e n t

T h e a u t h o r s w o u l d l i k e t o e x p r e s s t h e i r g r a t i t u d e t o Mrs. R u p p e r t ,

Mr. S u n k e a n d M r . S t u e v e f o r c a r r y i n g o u t t h e m e a s u r e m e n t s .

R e f e r e n c e s

/ I / B r e i m e s s e r , F . , P o p p i n g e r , M . , S c h w a i e r , A . , " P i e z o r e s i s t i v e p r e s s u r e s e n s o r w i t h s i l i c o n d i a p h r a g m " , S i e m e n s F o r s c h , u . E n t w i c k 1 . - B e r . V o l . 1 0 ( 1 9 8 1 ) No. 2 , p p 72-77

/ 2 / I n t i c h a r , L . , S c h n a p p e r , C . ; " E x p e r i m e n t a l s i m u l a t i o n o f a h e l i u m c o o l i n g s y s t e m f o r a s u p e r c o n d u c t i n q g e n e r a t o r " ; 8 t h I n t . C o n f . o n M a g n e t T e c h n o l o g y , MT-8, p a p e r 2 P 4 - 0 2 , G r e n o b l e , 5 - 9 S e p t . 1 9 8 3