Field Wiring Considerations; Analog Input Timing Signals - National Instruments NI 6221 User Manual

Field Wiring Considerations

Analog Input Timing Signals

© National Instruments Corporation
Using the DAQ Assistant, you can configure the channels for RSE or NRSE
input modes. Refer to the
Software section for more information about the DAQ Assistant.
Environmental noise can seriously affect the measurement accuracy of the
device if you do not take proper care when running signal wires between
signal sources and the device. The following recommendations apply
mainly to AI signal routing to the device, although they also apply to signal
routing in general.
Minimize noise pickup and maximize measurement accuracy by taking the
following precautions.
• Use DIFF AI connections to reject common-mode noise.
• Use individually shielded, twisted-pair wires to connect AI signals to
the device. With this type of wire, the signals attached to the positive
and negative input channels are twisted together and then covered with
a shield. You then connect this shield only at one point to the signal
source ground. This kind of connection is required for signals traveling
through areas with large magnetic fields or high electromagnetic
interference.
Refer to the NI Developer Zone document, Field Wiring and Noise
Considerations for Analog Signals, for more information. To access this
document, go to
ni.com/info
In order to provide all of the timing functionality described throughout this
section, M Series devices have a flexible timing engine. Figure 4-12
summarizes all of the timing options provided by the analog input timing
engine. Also refer to the
Routing and Clock Generation.
Configuring AI Ground-Reference Settings in
and enter the info code
Clock Routing section of Chapter 9,
4-25
Chapter 4 Analog Input
.
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M Series User Manual