National Instruments BNC-2142 User manual

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322545A-01 © Copyright 1999 National Instruments Corp. All rights reserved. September 1999
INSTALLATION GUIDE
BNC-2142 DESKTOP AND DIN RAIL-MOUNTABLE
BNC ADAPTER
This installation guide describes how to install and configure your
BNC-2142 accessory.
Introduction
The BNC-2142 is a desktop and DIN rail-mountable BNC adapter you
can connect directly to dynamic signal acquisition (DSA) devices. It
includes six BNC connectors for signal connections, and a 68-pin
I/O connector for connection to the PCI-445xand NI 455xDSA devices.
The BNC-2142 is ideal for simplifying connections between your
measurement apparatus and your DSA device in laboratory, test, and
production environments.
What You Need to Get Started
To set up and use your BNC-2142 accessory, you will need the following:
❑BNC-2142 BNC Adapter
❑BNC-2142 Desktop and DIN Rail-Mountable BNC Adapter
Installation Guide
❑PCI-445x or NI 455xdevice
❑SHC68-C68-A1 analog cable
Detailed specifications for the BNC-2142 are in the Specifications section
later in this guide.

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Connecting Signals to Your BNC-2142
This section describes how to connect field signals to your BNC-2142
accessory.
Table 1 describes the BNC connectors available on the front panel of your
BNC-2142.
Note All BNC connectors on the BNC-2142 are single-ended only. The outer shells of the
BNC connectors are in direct contact with the metal enclosure of the BNC-2142, which is
grounded via the SHC68-C68 analog cable shield to the chassis ground of your computer.
Caution Connecting ground-referenced sources to the analog inputs or ground-referenced
loads to the analog outputs may cause ground noise to be picked up from other electrical
equipment also referenced to the source or load ground. Additionally, if the source or load
ground is at a different electrical potential than the ground of the BNC-2142 and DSA
device, ground-loops may occur that can result in incorrect readings, and may damage the
BNC-2142, the DSA device, or the host computer. National Instruments is not liable for
damage resulting from these connections.
To avoid encountering these conditions, electrically isolate orfloat the source or load from
its reference ground to create single-ended connection with a single ground reference on
the BNC-2142.
Table 1. BNC-2142 Connector Signal Descriptions
Front Panel BNC
Connectors Signal Description
ACH<0..3> Single-ended Input Analog Channels 0
through 3
DAC0OUT Digital-to-AnalogConverter0Output—This
single-ended connector supplies the voltage
output of analog output channel 0.
DAC1OUT Digital-to-AnalogConverter1Output—This
single-ended connector supplies the voltage
output of analog output channel 1.

© National Instruments Corporation 3 BNC-2142 Installation Guide
Connecting Analog Inputs
You can use the BNC-2142 to measure floating analog input signals. The
BNC-2142 connects to the analog input channels on the PCI-445xand
NI 455xDSA devices via the ACH<0..3> BNC connectors.
Connecting Analog Outputs
The BNC-2142 connects to the analog output channels on the PCI-445x
and NI 455xDSA devices via the DAC0OUT and DAC1OUT BNC
connectors.
Cabling
The BNC-2142 has one 68-position 0.8 mm VHDCI connector on the rear
panel to connect to your DSA device.
Caution Do not connect the BNC-2142 to any device other than the National Instruments
PCI-445xand NI 455xDSA devices. Doing so can damage the BNC-2142, the DSA
device, or host computer. National Instruments is not liable for damages resulting from
these connections.

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Installing Your BNC-2142
Perform the following steps to connect your BNC-2142 to your DSA
device. Consult your computer user manual or technical reference manual
for specific instructions and warnings.
Note You can either place the BNC-2142 on a workbench near the host computer or use
the available DIN rail-mount kit.
1. Connect the BNC-2142 to your DSA device.
2. Connect the field signals to the BNC connectors. Refer to the
Connecting Signals to Your BNC-2142 section earlier in this guide for
more information.
When you have finished using your BNC-2142, turn off any powered
external signals connected to your BNC-2142 before you turn off your
computer.
Figure 1. Connecting the BNC-2142 to Your DSA Device
Warning The BNC-2142 is not designed for input voltages greater than ±42.4 V, even if a
user-installed voltage divider reduces the voltage to within the input range of the DSA
device. Input voltages greater than ±42.4 V can damage the BNC-2142, any device
connected to it, and the host computer. Overvoltage can also cause an electric shock hazard
for the operator. National Instruments is notliable for damage or injury resulting from such
misuse.
1 BNC-2142 2 Shielded Cable 3 DSA Device 4 Personal Computer
3
4
1
2

© National Instruments Corporation 5 BNC-2142 Installation Guide
Specifications
This section lists the specifications of the BNC-2142. These specifications
are typical at 25 °C unless otherwise specified.
Electrical
Max input voltage ..................................Each input should remain within
±42.4 V (30 Vrms) of ground
Field connection.....................................6 BNC connectors
(4 single-ended analog input
connectors, and 2 single-ended
analog output connectors)
Physical
Dimensions.............................................14.4 by 11.2 by 5.5 cm
(5.7 by 4.4 by 2.2 in.)
I/O connector..........................................One 68-pin 0.8 mm VHDCI
female connector
BNC connectors.....................................6
Environment
Operating temperature............................0 to 70 °C
Storage temperature ...............................–55 to 150 °C
Relative humidity...................................5% to 90% noncondensing