©
National Instruments Corporation
1-1
1
Introduction
This chapter describes the BNC-2140 accessory, lists what you need to get
started, explains how to unpack your BNC-2140, and describes optional
equipment.
Thank you for buying the BNC-2140 accessory for DSA.The BNC-2140 is
a signal conditioning accessory specifically designed for use with a
dynamic signal acquisition (DSA) series device. It interfaces four BNC
signal inputs and two BNC signal outputs directly to National Instruments
DSA products including the PCI-4451, PCI-4452, NI 4551, and NI 4552.
The BNC-2140 connects to Integrated Circuit Piezoelectric (ICP
®
)
accelerometers and microphone preamplifiers as well as any other voltage
source whose output is less than ±42.4 V.
Each input channel consists of an independent 4 mA current source suitable
for use with ICP type accelerometers and microphone preamplifiers. You
can manually enable or disable the ICP signal conditioning on a per channel
basis. When disabled, the BNC-2140 acts as a direct voltage input. You can
manually switch each input channel and each output channel from
differential (DIFF) to single-ended (SE) mode. In SE mode, the BNC shell
tethers to a clean analog ground through a 50
Ω
resistor.
The BNC-2140 receives power for the ICP signal conditioning from the
DSA plug-in board via the 68-pin high-density connector. A green LED
indicates when the ICP circuitry is powered on. When you do not require
ICP signal conditioning, you can manually turn off the power to the
circuits.
UM.book Page 1 Tuesday, July 14, 1998 10:37 AM
