Omega Engineering PCI-DAS1200 manual A /D Board, Common Ground / Differential Inputs

The following sections depict recommended input wiring schemes for each of the 8 possible input configuration/grounding combinations.

4.2.1 Common Ground / Single-Ended Inputs

Single-ended is the recommended configuration for common ground connections. However, if some of your inputs are common ground and some are not, we recommend you use the differential mode. There is no performance penalty (other than loss of channels) for using a differential input to measure a common ground signal source. However, the reverse is not true. The diagram below shows a recommended connection diagram for a common ground / single-ended input system

	l		ith
na					nd
Sig	ource		w
				on	G
	S		m
		om
		C			 

O ptional wire since signal source and A/D board share com m on ground

CH IN

LL G N D

I/O

C onnector

+

In p ut	To A /D
A m p

-

A /D Board

Signal source and A/D board sharing com m on ground connected to single-ended input.

4.2.2 Common Ground / Differential Inputs

The use of differential inputs to monitor a signal source with a common ground is an acceptable configuration, though it requires more wiring and offers fewer channels than selecting a single-ended configuration. The diagram below shows the recommended connections in this configuration.

			l
	na			ith
ig			e w			nd
S
		S	ourc	m	on	G
			om
			C				
								High
							CH
							CH	Low
			O ptional wire				LL G ND
			since signal source
			and A/D board share
			com mon g round				I/O
							Connector
							Required connection
							of LL G N D to C H Low

+

Input	To A/D
A mp

-

A /D Board

Signal source and A/D board sharing com m on ground connected to differential input.

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