Chapter 4 Connecting and Using Accessories and Transducers
Getting Started with SCXI 4-22 www.ni.com
Excitation Channel Signal Connections on the
SCXI-1122
The SCXI-1122 has a voltage (VEX) and a current excitation (IEX)
channel, which are available at the front connector. In addition, VEX/2 is
available for half-bridge and quarter-bridge transducers. Both channels are
isolated from earth ground up to 450 V
rms
working common-mode voltage.
Notice that the voltage and current excitation channels are electrically
isolated from each other but do not provide a safety isolation between them.
Warning
Exceeding the overvoltage protection or isolation rating on the excitation output
can damage the SCXI-1122, the SCXIbus, and the DAQ device. National Instruments is
not liable for any damages or injuries resulting from such signal connections.
Excitation Level
Each excitation channel of the SCXI-1122 has one level:
• Current excitation—1mA
• Voltage excitation—3.333 V
It is important that you do not exceed the maximum permissible load of
each channel as listed in Table 4-4.
Table 4-4. SCXI-1122 Maximum Load per Excitation Channel
Excitation Level Maximum Load
3.333 V
1mA
225 mA
5kΩ