6
Rack Mounting
Once you have completed the above installation instructions, you are ready to mount the TBX
assembly in your rack. If you are using the National Instruments TBX Rack-Mount Assembly,
refer to the TBX Rack-Mount Installation Guide for instructions. If you are not using this rack-
mount assembly, perform the following steps to mount the TBX assembly directly onto your
DIN rail.
1. Snap the TBX terminal block onto the DIN rail with a firm push.
To remove the TBX terminal block from the DIN rail, place a flathead screwdriver into the
slot above the terminal block base and pry it from the rail.
2. Install the SCXI chassis using the appropriate chassis rack-mount kit.
Signal Connection
The following warnings contain important safety information concerning the use of hazardous
voltage levels with TBX-1325 terminal blocks.
Warnings:
S
HOCK HAZARD
: Only qualified personnel aware of the dangers involved
should use the TBX-1325. If signal wires are connected to the terminal block,
dangerous voltage levels may exist even when the equipment is turned off.
Before you remove or work with any installed terminal block, disconnect the AC
power line or any high-voltage sources (>30 Vrms and 42.4 V peak, or 60 VDC)
that may be connected to the terminal block. National Instruments is
NOT
liable
for any damages or injuries due to misuse of high-voltage signals connected to
the terminal block.
When using the terminal block with high voltage levels, you must insulate all
signal wires appropriately to the highest voltage the terminal block may come in
contact with. National Instruments is
NOT
liable for any damages or injuries
resulting from inadequate signal wire insulation.
Any CHASSIS GROUND terminal on your terminal block is for grounding
high-impedance sources such as a floating source (1 mA maximum). Do not
use these terminals as safety earth grounds.
Operating common-mode voltage must not exceed 250 Vrms between banks or
from any bank to earth.
When connecting your field signals to the TBX-1325 high-voltage terminal block for use with
the SCXI-1124, follow the labeling on the TBX-1325 that matches the signal names from the
SCXI-1124 User Manual. For information regarding the function and use of the SCXI-1124
signals, consult your SCXI-1124 User Manual.
Read the next section, Voltage Drops, before proceeding with the signal connections.
