Isolatio n B arrie r
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Large | com |
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ode voltage signal | board |
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m | between | & A/D |
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G N D
W hen the voltage difference between signal source and A/D board ground is large enough so the A/D board’s comm on m ode range is exceeded, isolated signal conditioning m ust be added.
CH | H igh | + |
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| In p u t | To A /D |
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CH Low | - |
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10 K |
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LL GN D |
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I/O |
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C onnector |
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10K is a recom m ended valu e . You m ay short LL G N D to C H Low instead, b ut this w ill reduce your system ’s noise im m unity.
System with a Large C om m on Mode Voltage,
Connected to a Differential Input
4.2.6 Isolated Grounds / Single-Ended Inputs
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| CH IN |
| LL GND |
I/O
C o nn ector
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Inp ut |
| To A/D |
A m p |
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A /D Board
Isolated Signal Source
Connected to a
4.2.7 Isolated Grounds / Differential Inputs
Optimum performance with isolated signal sources is ensured with the use of the differential input setting. The diagram below shows the recommend connections in this configuration.
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| CH High |
G N D | + |
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These grounds are 
electrically isolated .
| Inp ut | To A /D |
| A m p | |
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CH Low | - |
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10 K |
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LL GND |
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I/O | A /D Board | |
C onn ector | ||
10K is a recom m e nded value . You m ay sho rt LL G N D to C H Low instead, b ut this w ill re duce yo ur system ’s noise im m u nity.
A lready isolated signal source and A/D board connected to a differential input.
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