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Chapter 1
Getting Started with the cDAQ Controller
7.
Install the power connector plug on the front panel of the cDAQ controller and tighten the
connector screw flanges.
8.
Turn on the external power source(s).
The cDAQ controller uses V1 if the voltage across V1 and C is 9 V or greater. If the V1-to-C
voltage drops below 9 V, the cDAQ controller switches to V2. If the V2-to-C voltage is less than
9 V, operation may be interrupted.
Note
If the cDAQ controller is using V1 and a secondary power source is
connected to V2, there is a small leakage current on V2. The leakage current depends
on the V2-to-C voltage. Refer to the
Power Requirements
section of the
specifications document for your cDAQ controller for nominal values of this leakage
current.
If the power source is connected to the power connector using long wiring with high DC
resistance, the voltage at the power connector may be significantly lower than the specified
voltage of the power source.
The C terminals are internally connected to each other but are not connected to chassis ground.
You can connect the C terminals to chassis ground externally. Refer to the
Power Requirements
section of the specifications document for your cDAQ controller for information about the
power supply input range. Refer to the
Safety Voltages
section of the specifications document
for your cDAQ controller for information about the maximum voltage from terminal to chassis
ground.
Mounting the cDAQ Controller
You can use the cDAQ controller on a desktop or mount it to a panel, wall, DIN rail, or rack. For
accessory ordering information, refer to the pricing section of the NI cDAQ-9138/9139 product
page at
.
Note
The cDAQ controller was designed and tested in multiple mounting
configurations. The varied mounting orientations or configurations can reduce the
maximum allowable ambient temperature and can affect the accuracy of C Series
modules in the controller. Visit
and enter the Info Code
cdaqmounting
for more information about mounting and accuracy.
The following sections contain instructions for the mounting methods. Before using any of these
mounting methods, record the serial number from the side of the controller. You may be unable
to read the serial number after you have mounted the controller.
Caution
You must mount the controller horizontally on a flat, vertical, metallic
surface using the NI panel mount kit, part number 781919-01, to achieve an allowable
operating ambient temperature of 45 to 55 °C. Mounting the controller in a different
orientation or on a nonmetallic surface reduces the maximum allowable ambient