Isolated Grounds / Single-Ended Inputs - Measurement Computing CIO-DAS1601/12 Manual

W hen the voltage difference
betw een signal source and
A /D board ground is large
enough so the A /D board's
com m on m ode range is
exceeded, isolated signal
conditioning m ust be added.
Figure 5-8. Common Mode Voltage > +/-10V. Differential Input
5.2.6

Isolated Grounds / Single-Ended Inputs

Single-ended inputs can be used to monitor isolated inputs, though the use of the differential mode will
increase you system's noise immunity. Figure 5-9 below shows the recommended connections is this
configuration.
C onne cte d to a S ingle-E nded Input
Figure 5-9. Isolated Grounds / Single-Ended Input
Iso latio n
B arrie r


G N D
1 0 K
1 0 K is a re c o m m e n d e d v a lu e . Yo u m a y s h o rt L L G N D to C H L ow
in s te ad , b ut th is w ill re d u c e y o u r s y s tem 's n o ise im m u nity.
S ystem w ith a La rge C om m on M ode Voltag e,
C onne cte d to a D ifferential Inp ut


I/O
C o nn ector
Iso lated S ignal S ource
C H H igh
+
In p u t
To A /D
A m p
C H Low -
LL G N D
I/O
A /D B o a rd
C o nn ec tor
CH IN
+
Inp ut
A m p
LL GND -
A /D B o ard
16
To A /D