Take the following precautions to minimize noise pickup and maximize measurement
accuracy:
•
Use differential 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 signal attached to the positive and negative inputs 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.
•
Route signals to the device carefully. Keep cabling away from noise sources, such as
video monitors and analog signals.
Use the following recommendations for all signal connections to the NI USB-7846R:
•
Separate NI USB-7846R signal lines from high-current or high-voltage lines. These lines
can induce currents in or voltages on the NI USB-7846R signal lines if they run in
parallel paths at a close distance. To reduce the magnetic coupling between lines, separate
them by a reasonable distance if they run in parallel or run the lines at right angles to each
other.
•
Do not run signal lines through conduits that also contain power lines.
•
Protect signal lines from magnetic fields caused by electric motors, welding equipment,
breakers, or transformers by running them through special metal conduits.
Mounting R Series USB Devices
You can use your R Series USB device on a desktop, mount it on a wall, or mount it on a DIN
rail.
Panel or Wall Mounting
Complete the following steps to panel or wall mount your NI USB-7846R. You can purchase
the panel mounting kit at
ni.com
with part number 781514-01.
1.
Use three #8-32 flathead screw to attach the backpanel wall mount to the panel or wall.
Tighten the screw with a #2 Phillips screwdrivers to a torque of 1.1 N · m (10 lb · in.).
2.
Place the NI USB-7846R on the backpanel wall mount with the signal wires facing down
and the device bottom sitting on the backpanel wall mount lip.
3.
While holding the NI USB-7846R in place, attach the front bracket to the backpanel wall
mount by tightening the two thumbscrews.
8
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ni.com
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NI USB-7846R User Manual
