Campbell Scientific CR9000X Measurement and Control System User Manual
Page 43
Overview
the bridge. See figure OV1-8 for an example of how to wire up a full
Wheatstone bridge using the VEX output and VRTN return channels.
V
E
E
EX
X
X
V
RTN
V
IN+
V
IN-
FIGURE OV1-8. Wiring a Wheatstone bridge
Channel Description
V
EX
Regulated DC voltage output. Can be set to 5 VDC or 10 VDC
and can source up to 85 mA. Must use the V
RTN
input for the
voltage return.
I
EX
Regulated 10 mA DC current output. Has a compliance voltage
of 12 Volts. Must use the I
RTN
input for the voltage return.
V
IN+
High side of the differential voltage input for measurement.
V
IN-
Low side of the differential voltage input for measurement.
V
RTN
Return, or ground plane, for V
EX
I
RTN
Return, or ground plane, for I
EX
System analog ground. Same reference ground as grounds on the
CR9050 and CR9060. Used mainly for shield drain.
It should be noted that the raw value returned from the VoltFilt measurement
is in millivolts. This is true even when measuring an electrical bridge that is
excited using one of the excitation options supplied by the CR9052DC
module. If it is desired to have a ratio-metric value returned (mVolts per
Volt), the applicable multiplier will need to be applied.
For example, if 5 volts were used to excite the Wheatstone bridge depicted in
Figure OV1-8, a multiplier of 0.2 (1/5) would need to be applied to have a
ratio-metric value returned.
The CR9052DC supports Hanning, Hamming, Blackman, and Kaiser-
Bessel windowing. Windowing may be shut off if desired. The CR9052DC
can also implement A, B, or C spectral weighting for all spectral output
modes as defined in the IEC 60651 international standard. It also supports 1/N
octave analysis (such as the 1.3 octave analysis) for acoustic applications.
CR9052DC SUPPORTED MEASUREMENT INSTRUCTIONSS:
VoltFilt
Differential Filter Measurement
FFTFilt
Differential FFT Measurement
See Section 3.3 CR9052 Filter Module Measurements for measurement details.
See Section 7 Measurement Instructions for Instruction details.
OV-11