Festo CPX-2AA-U-I, Electronic Manual

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3. An al ogu e i npu t modu le CPX− 4AE −I
3−28
F est o P. BE −CPX− A X− E N e n 0503 b
Data f orm at VZ + 15 b its li n ea r s c ale d"
Th e 12− b it d i g ital v al u es, wh i ch e x ist afte r t h e A −D conv e r si on
o f t h e a n al ogu e i npu t si gn als, a r e li n ea r l y s c ale d t o t h e d ata
r a ng e d efi n e d by t h e s c ali ng e nd v al u es (li m it v al u es) a nd
ou t pu t i n t h e i npu t word (see se c ti on 3. 4 .5, F i g .3 / 5).
Data f orm at VZ + 12 b its r i gh t−j u stifie d"
Th e 12− b it d i g ital v al u es, wh i ch e x ist afte r t h e A −D conv e r si on
o f t h e a n al ogu e i npu t si gn als, a r e ou t pu t unmod ifie d i n t h e
i npu t word (see als o e x a mp le i n se c ti on 3. 4 .1, F i g .3 / 3).
Data f orm at VZ + 15 b its left−j u stifie d" a nd
d ata f orm at VZ + 12 b its left−j u stifie d + d ia gno sis "
Th e 12− b it d i g ital v al u es, wh i ch e x ist afte r t h e A −D conv e r si on
o f t h e a n al ogu e i npu t si gn als, p l u s t h e pr e c e d i ng si gn b it a r e
a rr a ng e d left−j u stifie d i n t h e d ata f orm at. Th e t hr ee ze ro s at
t h e e nd c a u se t h e ou t pu t d ata word t o corr es pond t o t h e
12− b it d i g ital v al u e afte r A −D conv e r si on mu lti p lie d by 8
( prov i d i ng t h e r e is no w i r e f r a c t ur e d ia gno sis).
Th e f o ll ow i ng d ia gr a m s how s a n e x a mp le o f t h e d ata f orm at
VZ + 15 b its left−j u stifie d" :
1
An al ogu e i npu t
v al u es
2
Di g ital si gn als afte r
A −D conv e r si on
3
Av aila b le d i g ital
si gn als s c ale d t o t h e
e nd v al u e o f t h e d ata
r a ng e
1
2
3
32760
0 4 095
0
0 mA
4 mA
20 mA
20 mA
F i g .3 /4 : Ex a mp le o f d ata f orm at VZ + 15 b its left−j u stifie d"