Omega Engineering PCI-DAS1200 manual Board

Isolatio n B arrie r

	mon
Large	com
	ode voltage signal		board
m	between	& A/D
				
	source

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	+
		In p u t	To A /D
		A m p
CH Low		-
10 K
LL GN D
I/O		A/D Board
C onnector

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

Single-ended inputs can be used to monitor isolated inputs, though the use of the differential mode will increase your system’s noise immunity. The diagram below shows the recommended connections in this configuration.

	ted
ola				l
Is
			na
		sig		source

	
	CH IN
	LL GND

I/O

C o nn ector

+

Inp ut	To A/D
A m p

-

A /D Board

Isolated Signal Source

Connected to a Single-Ended Input

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.

				rce
			ou			ard
		l S
	na				o		.
ig				A/D	B
S			d				lated
			an		dy Iso
				Alrea				
								CH High

G N D +

These grounds are electrically isolated .

	Inp ut	To A /D
	A m p
CH Low	-
10 K
LL GND
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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