National Instruments SCC-A10 User manual

USER GUIDE
SCC-A10 Voltage Attenuator
Module
The SCC-A10 voltage attenuator module accepts up to two voltage sources
of 100 V maximum amplitude and attenuates each voltage by a factor of 10.
A differential instrumentation amplifier buffers each input signal. The
SCC-A10 contains circuitry capable of protecting E Series DAQ devices
for input signals up to 250 Vrms.
Conventions
The following conventions are used in this guide:
<> Angle brackets that contain numbers separated by an ellipsis represent
a range of values associated with a bit or signal name—for example,
P0.<3..0>.
»The »symbol leads you through nested menu items and dialog box options
to a final action. The sequence File»Page Setup»Options directs you to
pull down the File menu, select the Page Setup item, and select Options
from the last dialog box.
This icon denotes a note, which alerts you to important information.
This icon denotes a caution, which advises you of precautions to take to
avoid injury, data loss, or a system crash. When this symbol is marked on
the product, refer to the Read Me First: Safety and Radio-Frequency
Interference document, shipped with the product, for precautions to take.
When symbol is marked on a product, it denotes a warning advising you to
take precautions to avoid electrical shock.
When symbol is marked on a product, it denotes a component that may be
hot. Touching this component may result in bodily injury.

SCC-A10 Voltage Attenuator Module User Guide 2 ni.com
bold Bold text denotes items that you must select in software, such as menu
items and dialog box options. Bold text also denotes parameter names.
italic Italic text denotes variables, emphasis, a cross reference, or an introduction
to a key concept. This font also denotes text that is a placeholder for a word
or value that you must supply.
monospace Text in this font denotes text or characters that you should enter from the
keyboard, sections of code, programming examples, and syntax examples.
This font is also used for the proper names of disk drives, paths, directories,
programs, subprograms, subroutines, device names, functions, operations,
variables, filenames, and extensions.
SC-2345 SC-2345 refers to both the SC-2345 connector block and the SC-2345
configurable connector.
SCC SCC refers to any SCC Series signal conditioning module.
What You Need to Get Started
To set up and use the SCC-A10, you need the following items:
❑SC-2345/2350 with one of the following:
–SCC-PWR01
– SCC-PWR02 and the PS01 power supply
– SCC-PWR03—requires a 7 to 42 VDC power supply
(not included)
❑One or more SCC-A10 modules
❑SC-2345/2350 User Manual,available at ni.com
❑SCC Quick Start Guide,available at ni.com
❑SCC-A10 Voltage Attenuator Module User Guide
❑Read Me First: Safety and Radio-Frequency Interference
❑SC-2345 Quick Reference Label
❑68-pin E Series DAQ device, documentation, and 68-pin cable
❑1/8 in. flathead screwdriver
❑Numbers 1 and 2 Phillips-head screwdrivers

©National Instruments Corporation 3 SCC-A10 Voltage Attenuator Module User Guide
❑Wire insulation strippers
❑NI-DAQ (current version) for Windows 2000/NT/XP/Me
Note Software scaling of measurements is not supported on the Macintosh operating
system. Refer to the Using the SCC-A10 when Scaling Voltage Measurements section.
Device Specific Information
Note For general SCC module installation and signal connection information, and
information about the SC-2350 carrier, refer to the SCC Quick Start Guide, available for
download at ni.com/manuals.
Installing the Module
Caution Refer to the Read Me First: Safety and Radio-Frequency Interference document
before removing equipment covers or connecting/disconnecting any signal wires.
You can plug the SCC-A10 into any analog input socket on the SC-2345.
The socket you choose determines which E Series DAQ device channels
receive the SCC-A10 signals, as explained in the SCC Quick Start Guide.
For single-stage input conditioning, plug the SCC-A10 into any socket
J(X+1), where Xis 0 to 7, and connect the input-signal wires to the module
as described in the SCC Quick Start Guide.
If you use the SCC-A10 in a dual-stage configuration, the SCC-A10 must
be the first-stage module. Plug it into any socket J(X+9) and plug the
second-stage SCC into socket J(X+1), where Xis 0 to 7. Connect the
input-signal wires to the SCC-A10 as described in the SCC Quick Start
Guide. The SC-2345 connects the output signals of the SCC-A10 to the
inputs of the second-stage SCC. An example of dual-stage conditioning is
an SCC-A10 followed by a lowpass filter module (SCC-LPXX).
Sockets J9 to J16 are also available for digital input/output (DIO)
conditioning or control. Refer to the SC-2345/2350 User Manual for more
information about configuring, connecting, and installing SCC modules.

SCC-A10 Voltage Attenuator Module User Guide 4 ni.com
Connecting the Input Signals
Note The signal names have changed. Refer to ni.com/info and enter rdtntg to
confirm the signal names.
Each screw terminal is labeled by pin number <1..4>. Pins 1 and 2 form
a differential channel routed to E Series DAQ device channel X+8, and
pins 3 and 4 form a second differential channel routed to E Series DAQ
device channel X. The value of Xis determined by the number of the
SC-2345 socket where you plug in the module, J(X+1) or J(X+9).
The signal source can be floating or ground-referenced. Floating signal
sources do not require bias resistors to ground with the SCC-A10. Figure 1
shows the SCC-A10 signal connections.
Figure 1. SCC-A10 Signal Connections
For information about how to configure the SCC-A10 module using
NI-DAQmx, refer to the SCC Quick Start Guide.
Signal
Source
AI (X )
AI SENSE
AI (X+8)
SCC-A10
+
–
E Series DAQ Device
Overvoltage
Protection
Overvoltage
Protection
+
–
+
–
Overvoltage
Protection
Overvoltage
Protection
+
–
Signal source may be floating or ground-referenced.
1
3
4
2AI GND

©National Instruments Corporation 5 SCC-A10 Voltage Attenuator Module User Guide
Using the SCC-A10 when Scaling Voltage Measurements
If you configured the SCC-A10 using Measurement & Automation
Explorer (MAX) and you are using NI-DAQ, the voltage reading you get
from the E Series DAQ device accounts for the voltage scaling effect of the
SCC-A10. Otherwise, because the voltage measurement from the E Series
DAQ device is one-tenth of the voltage applied at the SCC-A10 input, you
must multiply the voltage reading from the E Series DAQ device by 10 to
get the correct SCC-A10 input voltage.
Specifications
Note In order for the SCC-A10 to perform according to the specifications in this guide,
the ±15 V power supply you use must be accurate to within 5%.
These ratings are typical at 25 °C unless otherwise stated.
Analog Input
Number of input channels ...................... 2 DIFF
Input range ............................................. ±100 VDC
Input impedance ..................................... 1 MΩ(powered on or off)
Gain error ............................................... ±0.14% of reading max1
Gain-error temperature coefficient......... ±0.006% of reading/°C max
Offset error............................................. ±6.5 mV max (referred to
input [RTI]2)
Offset-error temperature coefficient ...... ±80 µV/°C max (RTI)
Nonlinearity ........................................... ±0.004% of full scale
Common-mode rejection ratio ............... 60 dB min (DC to 60 Hz)
1 Temperature range is 23 °C ±5 °C.
2 Calculated with respect to the input range

SCC-A10 Voltage Attenuator Module User Guide 6 ni.com
Dynamic Response
Bandwidth (–3 dB) .................................10 kHz
Output settling time to within
0.01% of nominal input voltage .............15 µs
Output slew rate......................................0.75 V/µs min
Power Requirement
Analog power .........................................100 mW max
+15 V ...............................................3.2 mA max
–15 V ...............................................3.2 mA max
Digital power (+5 V) ..............................0.0 mA
Physical
Dimensions .............................................8.89 cm ×2.92 cm ×1.85 cm
(3.5 in. ×1.15 in. ×0.73 in.)
I/O connectors.........................................One 20-pin right-angle
male connector,
one 4-pin screw terminal
Wire gauge range....................................24 to 12 AWG
Maximum Working Voltage
Maximum working voltage refers to the signal voltage plus the
common-mode voltage.
Channel-to-earth .....................................100 V, Installation Category I
Channel-to-channel.................................100 V, Installation Category I
Environmental
Operating temperature ............................0 to 50 °C
Storage temperature ................................–20 to 70 °C
Humidity.................................................10 to 90% RH, noncondensing
Maximum altitude...................................2,000 m
Pollution Degree (indoor use only) ........2

©National Instruments Corporation 7 SCC-A10 Voltage Attenuator Module User Guide
Safety
The SCC-A10 meets the requirements of the following standards for safety
and electrical equipment for measurement, control, and laboratory use:
• IEC 61010-1, EN 61010-1
• UL 3111-1:UL 61010B-1
• CAN/CSA C22.2 No. 1010.1
Note For UL and other safety certifications, refer to the product label, or visit
ni.com/hardref.nsf, search by model number or product line, and click the
appropriate link in the Certification column.
Electromagnetic Compatibility
Emissions ............................................... EN 55011 Class A at 10 m
FCC Part 15A above 1 GHz
Immunity................................................ EN 61326:1997 + A2:2001,
Table 1
CE, C-Tick, and FCC Part 15 (Class A) Compliant
Note For full EMC compliance, operate this device with shielded cabling.
CE Compliance
This product meets the essential requirements of applicable European
Directives, as amended for CE marking, as follows:
Low-Voltage Directive (safety) ............. 73/23/ECC
Electromagnetic Compatibility
Directive (EMC) .................................... 89/336/EEC
Note Refer to the Declaration of Conformity (DoC) for this product for any
additional regulatory compliance information. To obtain the DoC for this product,
visit ni.com/hardref/nsf, search by model or product line, and click the appropriate
link in the Certification column.

SCC-A10 Voltage Attenuator Module User Guide 8 ni.com
SCC-A10 Module Pin Assignments
Figure 2 shows the I/O connector pins on the bottom of the module.
Figure 2. SCC Module Bottom View
Table 1 lists the signal corresponding to each pin. AI (X) and AI (X+8) are
the analog input signal channels of the E Series DAQ device. AI GND is
the analog input ground signal and is the reference for AI (X) and AI (X+8).
A GND is the reference for the ±15 V power supply. AI GND and A GND
connect to the SC-2345 at the SCC-PWR connector.
1Pin1 2Pin2 3PWBKey 4 Pin 19 5Pin20
Table 1. SCC-A10 Module Pin Assignments
Pin Number Signal
1E Series AI (X)
2E Series AI GND [AI (X) REF]
3 —
4E Series AI (X+8)
5 —
6E Series AI GND
7 —
8E Series AI GND [AI (X+8) REF]
9 —
10 —
5
4
2
1
3

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© 2001–2004 National Instruments Corp. All rights reserved.
371067B-01 Mar04
*371067B-01*
11 A GND
12 —
13 +15 V
14 –15 V
15 —
16 —
17 —
18 —
19 —
20 —
Table 1. SCC-A10 Module Pin Assignments (Continued)
Pin Number Signal