Advantech PCL-818L, User Manual

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22 PCL-818L User's Manual
Correct signal connections are one of the most important factors to
consider if your application is to send and receive data with accuracy.
Good signal connections can also avoid a lot of unnecessary damage
to your valuable PC and other hardware. This chapter provides
information on signal connections for different types of data acquisi-
tion applications.
Analog input connections
The PCL-818L supports either 16 single-ended or eight differential
analog inputs. Jumper JP7 selects the input channel configuration.
The major difference between single-ended and differential input
connections is the number of signal wires per input channel.
Single-ended channel connections
Single-ended connections use only one signal wire per channel. The
voltage on the line references to the common ground on the card. A
signal source without a local ground is called a “floating” source. It is
fairly simple to connect a single-ended channel to a floating signal
source. A standard wiring diagram looks like this:
Differential channel connection
The differential input configuration uses two signal wires per channel.
The card measures only the voltage difference between these two
wires, the HIGH wire and the LOW wire. If the signal source has no
connection to ground, it is called a “floating” source. A connection
Signal Input
To A/D
A.GND
A.GND
+
Vs
-