©
National Instruments
11
NI 9155 Operating Instructions and Specifications
1.
Connect the positive lead of the power supply to the V1 or V2 terminal
of the COMBICON connector shipped with the NI 9155.
2.
Connect the negative lead of the power supply to one of the C terminals
of the COMBICON connector.
3.
Optionally, you can connect the positive lead of another power supply
to the other V terminal and the negative lead to one of the C terminals.
4.
Install the COMBICON connector on the front panel of the NI 9155.
Caution
To ensure the specified EMC performance, do not connect the power input to a
DC mains supply or to any supply requiring a connecting cable longer than 3 m (10 ft).
A DC mains supply is a local DC electricity supply network in the infrastructure of a
certain site or building.
Note
The chassis draws power from
either
V1 or V2 depending on which terminal has a
higher voltage. It does not draw power from both terminals. The chassis switches between
V1 and V2 without affecting operation.
Note
If you prefer for the chassis to draw power from one power supply, you must ensure
that the voltage of that power supply, measured at the chassis power connector, is at least
500 mV higher than the voltage of the other power supply.
Caution
The C terminals are internally connected to each other. If you use two power
supplies, make sure that they share a common ground.
Caution
The C terminals are internally connected to the body of the chassis to prevent a
faulty ground connection from causing the chassis ground to float. If you reverse the input
voltage, the positive input voltage is connected directly to the chassis. The chassis has
built-in reversed-voltage protection, but reversed voltage can damage connected
peripherals if the chassis ground is not reliably connected to earth ground.
Caution
Do not tighten or loosen the terminal screws on the power connector while the
power connector is plugged into the chassis or while the power supply is on.
Connecting One or More NI 915x Chassis
to the MXI-Express Host System
Complete the following steps to connect one or more NI 915x chassis to a
MXI-Express host system.
1.
Make sure the MXI-Express host system is set up and configured as
described in the
MXI-Express (x1) for PXI Express User Manual
.
2.
If the MXI-Express host system is powered up, power it down.
3.
If the NI 915x is powered up, power it down.
