DT9847 Series

Dynamic Signal Analyzer for USB
With Low THD and Wide Dynamic
Range
Overview
The DT9847 Series are high-accuracy, dynamic signal
acquisition modules designed for sound and vibration
applications. These modules are ideal for precision
measurements with microphones, accelerometers, andother transducers that have a large dynamic range.
Common applications include audio, acoustic, andvibration testing.

The DT9847 Series features ultra-low total harmonic
distortion (THD) of 102 dB and wide dynamic range up to
123 dB for precision measurements in sound and vibration
applications.

Combine the DT9847 with the ready-to-measure
QuickDAQ application to create a powerful FFT Analyzer
instrument. Additionally, all Data Translation devices
include comprehensive driver and software support,
and interface tools for LabVIEW™ and MATLAB®
programmers.

oo Up to two 32-bit D/A converters
oo Single value, waveform, and continuous

streaming output
oo Programmable output rate from 30 kS/s to

216 kS/soo Output range of ±10 V and ±3 V
oo Software-programmable trigger source(software trigger or external digital trigger) to
start the analog output operation• Internal clock source (shared between the analog
input and analog output subsystems)• Sync Bus (RJ45) connector for synchronizing
acquisition on up to four DT9847 Series modules

Key Features• Simultaneous analog input and waveform analog
output operations• Analog input subsystem:oo Up to three, simultaneous 24-bit A/D converters
oo Sample rate from 1 kS/s to 216 kS/soo Input range of ±10 V with software-selectable

Supported Operating Systems• Windows® 10/8/7/Vista® 32/64-bit

gains of 1 and 10 for an effective input range of±10 V and ±1 V
oo Support for Integrated Electronic Piezoelectric(IEPE) inputs, including use of a 4 mA current
source with 18 V compliance voltage for AC or
DC couplingoo Supports a start trigger for acquiring pre-trigger
samples and a reference trigger for acquiring
post-trigger samples. Specify the number ofpost-trigger samples to acquire before stopping
the operation.
oo For the start trigger, supports a softwareprogrammable trigger source (software, external
digital trigger, or a positive- or negative-going
analog threshold trigger on any of the analog
input channels). The threshold trigger can be
programmed for a value from ±10 V.
oo For the reference trigger, supports a positive- or
negative-going analog threshold trigger on anyof the analog input channels. The threshold
trigger can be programmed for a value from ±10
V.
• Analog output subsystem:(508) 946-5100

Analog Input Channels
The DT9847-2-2 module provides two analog input
channels and the DT9847-3-1 module provides three
analog input channels. These are single-ended channels;
IEPE sensors can be connected to these inputs. Softwareselectable gains of 1 and 10 provide effective input
ranges of ±10 V and ±1 V. The DT9847 Series modules use
24-bit Delta-Sigma analog-to-digital converters (ADCs)
that provide anti-aliasing filters based on the clock rate.
These filters remove aliasing, which is a condition wherehigh frequency input components erroneously appear as
lower frequencies after sampling.
DT9847 Series modules can acquire a single value froma single analog input channel, a single value from all theanalog input channels simultaneously, or multiple values
from a group of analog input channels.

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IEPE Functions

Programmable A/D ClockApplications that require accelerometer, vibration, noise,or sonar measurements often use IEPE sensors. IEPE
conditioning is built-in to the analog input circuitry of
the DT9847 Series modules. The modules support thefollowing software-programmable IEPE functions foreach of the analog inputs:

The DT9847 Series modules support an internal clock,which is derived from the USB clock. Use software to
specify the internal clock source and the frequency atwhich to pace the input and output operations and to
start the sample clock. The sampling frequency ranges
from 1 kHz to 216 kHz.

• Excitation current source — The DT9847 Series
modules provide an internal excitation current
source of 4 mA. Enable or disable the use of a 4 mA,
internal excitation current source using software. Bydefault, the excitation current source is disabled.
• Coupling type — Select whether AC coupling or DC
coupling is used. By default, DC coupling is selected
for the DT9847 Series modules.

Exceptional performance of the DT9847 is illustrated in the FFT diagram. The D/A stimulus signal of ±20 µV at 4.98 kHz is fed
back into the A/D input. The A/D is sampling at 50 kS/s/ch.
The IBF (input Below Full Scale) is –113.6 dB, the signal-to-noise plus distortion is –9.12 dB, the ENOB (Effective Number of Bits)
is 17.1.
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+18 Volts
4mA
1M

Ain 0

AC - DC
Coupling

x1 / 1024 BitA/D
A/D PLL
Programmable
Clock+18 Volts
4mA
1M

Ain 1

AC - DC
Coupling

x1 / 1024 BitA/D

USB 2.0
High Speed
Interface

D/A PLL
Programmable
Clock
Control
Logic

Sync Bus Clock& Trigger+18 Volts
4mA
1M

Ain 2

AC - DC
Coupling

x1 / 10RJ45

24 BitA/D
32 Bit D/AConverter

100kHzFilterD/A Output 0

Ext. Trigger

15-pinConnector

USB 2.0

Digital In
Digital Out

Block Diagram of DT9847-3-1 module.

+18 Volts
4mA
1M

Ain 0
+18 Volts

AC - DC
Coupling

x1 / 10

4mA
1M

Ain 1

AC - DC
Coupling

100kHzFilterx1 / 1024 BitA/D

24 BitA/D

A/D PLL
ProgrammableClock

USB 2.0
High Speed
Interface

D/A PLL
Programmable
Clock

Sync Bus Clock& Trigger

Control
Logic

RJ45
32 Bit D/AConverter

32 Bit D/AConverter

D/A Ouput 1

100kHzFilterD/A Output 0

Ext. Trigger

15-pinConnector

USB 2.0

Digital In
Digital Out

Block Diagram of DT9847-2-2 Module.

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Analog Input Conversion Modes

Input Triggers

DT9847 Series modules support single-value, singlevalues, and continuous scan conversion modes:

A trigger is an event that occurs based on a specified
set of conditions. On the DT9847 Series modules, astart trigger source and a reference trigger source canbe specified. Pre-trigger acquisition starts when thestart trigger event occurs. When the reference trigger
occurs, pre-trigger data acquisition stops and post-trigger
acquisition starts. Post-trigger acquisition stops when thenumber of samples specified for the post-trigger scancount has been reached.

• Single-Value Operations — Specify the analog
input channel and the gain to be used. The module
acquires the data from the specified channel andreturns the data immediately.
• Single-Values Operations — Use a single-values
operation to read a single value from all the analog
input channels simultaneously using one software
call. Specify the analog input subsystem and thegain for the channels (not the channels themselves).
The module then acquires a value from each input
channel simultaneously; the data is returned as anarray of input values.
• Continuous Scan Mode — Continuous scan modetakes full advantage of the capabilities of theDT9847 Series modules. Specify a channel list, clock
frequency, start trigger, reference trigger, posttrigger scan count, and buffer using software.

Start Trigger Sources
The DT9847 Series modules support the following trigger
sources for the start trigger:• Software trigger — A software trigger event occurs
when you start the analog input operation (thecomputer issues a write to the module to begin
conversions). Using software, specify the start
trigger source as a software trigger.
• External digital (TTL) trigger — An external digital(TTL) trigger event occurs when the module detects
a rising- or falling-edge transition on the signal
connected to the External Trigger pin (pin 13) of theDigital I/O and External Trigger connector on themodule. Using software, specify the trigger source
as an external, positive digital (TTL) trigger or an
external, negative digital (TTL) trigger.

On the DT9847-2-2 module, you can enter up to two
entries in the channel list (analog input channels
0 and 1). On the DT9847-3-1 module, you canenter up to three entries in the channel list (analog
input channels 0 to 2). Using software, specify thechannels you want to sample in sequential order
When the start trigger is detected, the module
simultaneously acquires pre-trigger data from all of
the input channels specified in the channel list. The
sampled data is placed in the allocated buffer(s).
When the reference trigger occurs, pre-trigger
data acquisition stops and post-trigger acquisition
starts. The operation continues until the number ofsamples specified for the post-trigger scan count isacquired; at that point, the operation stops. The
conversion rate is determined by the frequency of
the input sample clock.

Note: If you configure the synchronization mode asslave, the Sync Bus connector accepts trigger andclock signals from the master; you cannot use the
Ext Trig connector on the slave module.

• Analog threshold trigger — The start trigger event
occurs when the signal attached to a specified
analog input channel in the channel list rises aboveor falls below a user-specified threshold level. Using
software, specify the following parameters:
oo Start Trigger source — Specify a positive (low-tohigh transition) threshold trigger if you want totrigger when the signal rises above a thresholdlevel, or a negative (high-to-low transition)
threshold trigger if you want to trigger when thesignal falls below a threshold level.
oo Threshold channel — Specify any one of theanalog input channels that are included in thechannel list as the threshold input channel.
oo Threshold level — Specify a value between ±10
V for a gain of 1 or ±1 V for a gain of 10 as thethreshold level.
• Sync Bus trigger — When multiple DT9847 Series
modules are connected together using the Sync Bus(RJ45) connector, you can use the Sync Bus trigger
as the start trigger of the slave module by setting
the synchronization mode of module to Slave. In thisconfiguration, any other start trigger for the slave
module is ignored.

Using software, you can stop a scan by performing either
an orderly stop or an abrupt stop. In an orderly stop, themodule finishes acquiring the current buffer, stops all
subsequent acquisition, and transfers the acquired data
to host memory; any subsequent triggers are ignored.
In an abrupt stop, the module stops acquiring samples
immediately; the current buffer is not completely filled, it
is returned to the application only partially filled, and any
subsequent triggers are ignored.

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Reference Trigger Sources

Output Conversion Modes

The DT9847 Series modules support the following sources
for the reference trigger:

The DT9847 Series modules support single-value,
waveform, and continuous analog output operations.

• External digital (TTL) trigger – The reference trigger

Single-Value Mode

event occurs when the module detects a rising- or
falling-edge transition on the signal connected to
the External Trigger pin (pin 13) of the Digital I/O
and External Trigger connector on the module.
• Analog threshold trigger –The reference trigger
event occurs when the signal attached to a specified
analog input channel in the channel list rises aboveor falls below a user-specified threshold value.
Using software, specify a positive (low-to-hightransition) threshold trigger or a negative (high-tolow transition) threshold trigger, the analog input
channel to use as the threshold channel, and thethreshold level.
• Sync Bus trigger — When multiple DT9847 Series
modules are connected together using the Sync Bus(RJ45) connector, set the reference trigger of a slave
DT9847 Series module to Sync Bus to receive a Sync
Bus trigger from one of the other modules to stop
pre-trigger and start post-trigger acquisition.

Single-value mode is the simplest to use but offers theleast flexibility and efficiency. Use software to specify
the analog output channel that you want to update,
and the value to output from that channel. The value
is output from the specified channel immediately. For asingle-value operation, you cannot specify a clock source,
trigger source, or buffer. Single-value operations stop
automatically when finished; you cannot stop a singlevalue operation.

Waveform Generation Mode
Waveform generation mode is supported on both theDT9847 Series modules. In this mode, a waveform, whichis specified in a single buffer, is output repetitively. The
waveform pattern can range from 2 to 8192 samples if
you are using one analog output channel or from 2 to4096 if you are using two analog output channels.
The host computer transfers the entire waveform pattern
to the 8 kilosample output FIFO on the module when
the trigger is detected. The module starts writing output
values to the analog output channels at the specified
clock rate. The module recycles the data, allowing you
to output the same pattern continuously without any
further CPU or USB bus activity.

Analog Output Channels
The DT9847-3-1 module supports one analog output
channel (0) through analog output subsystem 0. The
DT9847-2-2 module supports two analog output channels(0 and 1) through analog output subsystem 0. The
DT9847 Series modules provide a two-pole, 100 kHz
Butterworth filter to prevent noise from interfering withthe output signal.

When it reaches the end of the FIFO, the module returns
to the first location of the FIFO and continues outputting
the data indefinitely until you stop it.

The DT9847 Series modules can output bipolar analog
output signals in the range of ±3 V and ±10 V, with a gainof 1. The resolution of the analog output channel is fixedat 32-bits.

Continuous Analog Output Operations
Use continuously paced analog output mode tocontinuously output buffered values to the analog
output channel at a specified clock frequency. The
DT9847 Series modules support the ability to start
continuous analog output operations and continuous
analog input operations simultaneously.

The clock frequency for the D/A output clock on theDT9847 Series modules can be programmed to a value
between 30 kHz and 216 kHz.
Use software to specify an internal clock source andto specify the clock frequency for the analog output
subsystem.

Use software to fill the output buffer with the values
that you want to write to the analog output channels.
For example, if your output channel list contains analog
output channels 0 and 1, specify the values in the output
buffer as follows: the first output value for analog output
channel 0, the first output value for analog output
channel 1, the second output value for analog output
channel 0, the second output value for analog output
channel 1, and so on.

Due to the group delay of the Delta-Sigma D/A converter,
the DT9847 Series modules require 36 clock pulses once
the analog output sample clock is started before the first
D/A conversion is completed.

When it detects a trigger, the module starts writing thevalues from the output buffer to the channels specified in
the output channel list at the specified clock frequency.
The operation repeats continuously until all the data is
output from the buffers or you stop the operation.

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Output Triggers

You can start acquisition on multiple modules byconnecting all modules to a shared external trigger
input. When triggered, the modules start acquiring dataat the same time. Using this connection scheme, themeasurements of one module may not be synchronouswith the measurements of another module due to logic
delays in the clocking and USB circuitry.

The DT9847 Series modules support the following trigger
sources for starting analog output operations:• Software trigger — A software trigger event occurs
when you start the analog output operation (thecomputer issues a write to the module to begin
conversions). Using software, specify the trigger
source for D/A subsystem 0 as a software trigger.
• External digital (TTL) trigger — An external digital(TTL) trigger event occurs when the module detects
a rising- or falling edge transition on the signal
connected to the External Trigger pin (pin 13) of theDigital I/O and External Trigger connector on themodule. Using software, specify the trigger source
for D/A subsystem 0 as an external, positive digital(TTL) trigger or an external, negative digital (TTL)
trigger.

Synchronizing Acquisition on Multiple DT9847
Series Modules
DT9847 Series modules provide a Sync Bus (RJ45)
connector that can be used to connect and synchronize
multiple DT9847 Series modules. In this scheme, one
module is the master and the other modules are theslave. You specify the synchronization mode (master,slave, or none) of the A/D subsystem using software.

Note: If you configure the synchronization mode asslave, the Sync Bus connector accepts trigger andclock signals from the master; you cannot use the
Ext Trig BNC connector on the slave module.

• Sync Bus trigger — When multiple DT9847 Series
modules are connected together using the Sync Bus(RJ45) connector, you can use the Sync Bus trigger
as the start trigger of the slave module by setting
the synchronization mode of module to Slave. In thisconfiguration, any other start trigger for the slave
module is ignored.

A Master/Slave connection allows two modules to operatein perfect synchronization for up to 6 IEPE inputs.

When configured as a master, the Sync Bus connector
outputs trigger and clock signals. When configured as aslave, the Sync Bus connector accepts trigger and clock
signals from the master; the start trigger source on theslave module in is ignored in this configuration since theSync Bus is used as the start trigger.

Digital I/O Lines
The DT9847 Series modules support one digital input
port, consisting of 4 digital input lines (lines 0 to 3) and
one digital output port, consisting of 4 digital output
lines (lines 0 to 3). The resolution is fixed at 4 bits.

When configured as none (the default mode), theDT9847 Series module uses the USB clock instead of theSync Bus connector. The synchronization mode remains
set until changed or until the application exits.

You can read all 4 digital input lines or write all 4 digital
output lines with a single-value digital I/O operation. A
digital line is high if its value is 1; a digital line is low if its
value is 0. On power up or reset, a low value (0) is output
from each of the digital output lines.

Triggering Acquisition on Multiple Modules
Acquisition on multiple DT9847 Series modules can besynchronized using the Sync Bus (RJ45) connector.
The internal clock on the DT9847 Series modules when
the synchronization mode is none, is derived from theUSB clock and provides the timing for both the analog
input and analog output subsystems on the module.

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QuickDAQ

You can connect multiple modules in one of two
ways. The following diagram shows how to connect
a maximum of two DT9847 Series modules by daisy
chaining them together through the Sync Bus connector.

QuickDAQ allows you to acquire and display from all
Data Translation USB and Ethernet data acquisition
devices that support analog input streaming. Combine
QuickDAQ with Data Translation hardware to acquiredata, record data to disk, display the results in both aplot and digital display, and read a recorded data file.
Be productive right out of the box with this powerfuldata logging software. Data can be exported to otherapplications like Microsoft Excel® and The Mathworks
MATLAB® for more advanced analysis. Two additional
options can be purchased to add FFT analysis capabilities
to the base package.

Key Features• QuickDAQ Base Package (Free)
oo Ready-to-measure application software
oo Configure, acquire, log, display, and analyze yourdata
oo Customize many aspects of the acquisition,

display, and recording functions to suit yourneeds
• FFT Analysis Option (License Required)oo Includes all the features of the QuickDAQ Base
Packageoo Perform single-channel FFT operations including:◊ Auto Spectrum◊ Spectrum◊ Power Spectral Density
oo Configure and view dynamic performancestatistics
oo Supports Hanning, Hamming, Bartlett, Blackman,
Blackman Harris, and Flat Top response windows• Advanced FFT Analysis Option (License Required)oo Includes all the features of the QuickDAQ Base
Package and FFT Analysis Package
oo Perform 2-channel FFT operations including:◊ FRF◊ Cross-Spectrum◊ Cross Power Spectral Density◊ Coherence◊ Coherent Output Poweroo Supports real, imaginary, and Nyquist display
functionsoo Additional FFT analysis functions supported:
Exponential, Force, Cosine Taperoo Save data to .uff file format

Synchronizing two DT9847 Series modules by daisy chaining
the RJ45 connectors (shown using external trigger)

The following diagram shows how to connect amaximum of four DT9847 Series modules by using an
RJ45 distribution panel, such as an EP386, where thepanel contains four RJ45 connectors that are wired inparallel.

Synchronizing four DT9847 Series modules by using theEP386 RJ-45 Distribution Panel.

When synchronizing multiple modules, start the slave
modules before starting the master module. When themaster module is triggered (using any of the supported
trigger sources), both the master and the slave modules
start acquiring data at the same time (within one A/D
conversion of the clock). Note that you can set the clock
rate to be the same or different on each module.
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QuickDAQ with Advanced FFT Analysis Option.

Software Options

QuickDAQ Advanced FFT Function Examples

The following software is available for use with thismodule and is provided on the Data Acquisition Omni
CD:

The following plots show how you can use the DT9847
module with the Advanced FFT functions in QuickDAQ
to analyze data from a sweep test. Single FFT andtwo-channel FFT functions are shown. Two-channel FFT
functions compare the spectrum of a reference channel,
which outputs a stimulus, to the spectrum of a response
channel, which measures the effect of the stimulus.

• Device Driver — The device driver allows you to
use the DAQ module with any of the supported
software packages or utilities.
• Calibration Utility — This utility allows you tocalibrate features of the DAQ module.
• DT-Open Layers® for .NET Class Library — Use thisclass library if you want to use Visual C#® or Visual
Basic® for .NET to develop application software
for a DAQ module using Visual Studio® 2003-2012;
the class library complies with the DT-Open Layers
standard.
• DataAcq SDK — Use the DataAcq SDK to use Visual
Studio 6.0 and Microsoft® C or C++ to develop
application software for a DAQ module using
Windows 10/8/7/Vista/XP 32/64-bit; the DataAcq
SDK complies with the DT-Open Layers standard.
• DAQ Adaptor for MATLAB — Data Translation’s
DAQ Adaptor provides an interface between the
MATLAB® Data Acquisition (DAQ) toolbox fromThe MathWorks™ and Data Translation’s DT-Open
Layers architecture.
• LV-Link — Data Translation’s LV-Link is a library of
VIs that enable LabVIEW™ programmers to accessthe data acquisition features of DT-Open Layers
compliant USB and PCI devices.

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AutoSpectrum Response Channel

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Frequency Response Function

FRF – Phase

FRF – Real and Imaginary

Power Spectral Density

Coherence Reference Response(508) 946-5100

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Cross-Series Compatibility

Ordering Summary

Virtually all Data Translation data acquisition modules are compatible
with the DT-Open Layers® software standard. This means any application
developed with one of Data Translation’s software products can easily be
upgrade to a new Data Translation module with little to no reprogrammingneeded.

HARDWARE• DT9847-2-2• DT9847-3-1
ACCESSORIES• BNC DIN-RAIL KIT• EP386 — RJ45 Patch Panel, contains four
RJ45 connectors that are wired in parallel,
to connect four modules together using theSync BusFREE SOFTWARE• QuickDAQ• DAQ Adaptor for MATLAB• LV-Link
OPTIONAL SOFTWARE• QuickDAQ FFT Analysis Option (License
Required)• QuickDAQ Advanced FFT Analysis Option(License Required)(508) 946-5100
		
DT9847-Datasheet		

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June 2017. Rev 6© Measurement Computing Corporation