Signal Connections
35
ADLINK Technology Inc.
PCI-9524
Copyright 2008
User’s Manual
using when connecting to the transducer. A lengthy extension
cable between PCI-9524 and the terminal board inevitably has
some lead resistance that results in voltage drop; looping-back the
excitation on the terminal board creates a six-wire connection and
compensates for voltage drop.
A better approach is to use specially designed load-cell transduc-
ers having two additional SENSE terminals. The voltage difference
across the bridge excitation junctions is fed back to the voltage
excitation circuitry by two separate 'sense-wires', to further correct
the voltage drops due to the resistance in the excitation wiring. Be
sure to enable the remote-sense function to take full advantage of
a six-wire connection. A typical six-wire connection is shown in
Figure 3-5.
Figure 3-5: Connecting to a six-terminal load-cell transducer
using a six-wire connection
+Vex
+Vo
-Vex
-Vo
Load-cell Transducer
+Sense
-Sense
AI
n
+
AIn-
VEX
n
+
VEX_SEN
n+
VEX
n-
VEX_SEN
n-
NC
NC
Whether to use a six-wire connection is dependent on the imped-
ance of the load-cell transducers you are using, length of the wir-
ing cable, wire-gauge inside the cable, and the required
measurement accuracy. We recommend you to use a six-wire
connection as the default connection method for high-accuracy
load-cell transducers.
