Data Acquisition for the 21st Century
Like a butterfly emerging from a caterpillar, DAQ
technology is ready to take off in new directions
The following is a manuscript for an article published in R&D
magazine. R&D magazine holds the copyright for the finished
C.G. Masi, Contributing Editor
The start of the 21st Century finds data acquisition technology
in an odd position. Over the past (approximately) twenty five years,
DAQ technology has grown from the lunatic-fringe of the test and
measurement world to become the core architecture for measurement
systems. Just about every piece of equipment more complicated than
a ball-point pen now incorporates an embedded DAQ system. In the
process-control world, systems have nearly all gone to digital-computer-based
automation with clearly identifiable DAQ systems providing the feedback
needed to keep the systems on track. In the R&D world, DAQ technology
for collecting physical-measurement data has become an absolute
necessity. Scientists and engineers might consider substituting
design calculations for building physical prototypes, but manually
collecting data for serious research would be unthinkable.
While data-acquisition technology has become ubiquitous in all
forms of instrumentation systems, it has managed to do so without
quite becoming respectable. The interactive display used to monitor
the operation of an automated chemical processing plant, for example,
isn't a "Graphical User Interface." That's a DAQ term!
Instead, the process-control folks call it a "Human-Machine
The problem, of course, is simply one of perception. Many folks
still have the mental image that data acquisition is just "those
little plug-in cards." In fact, what has been happening is
that DAQ-system developers--that includes system integrators as
well as hardware and software vendors--have been pushing the envelope
to develop advanced instrument-system technologies. If you look
at what the DAQ community is working with now, you will see the
technology everyone else will be using some years hence. The best
way, therefore, to peer into the future of measurement-system technology,
is to ask what DAQ developers are developing.
R&D assembled a panel of experts from six companies (Agilent
Technologies, Capital Equipment Corporation, Data Translation, IOtech,
Keithley Instruments, and National Instruments) that are leaders
in developing instrument systems based on DAQ technology, and asked
them what the future will bring. Here is what they told us:
Where are we now?
"In general," says Dr. Michael Kraft, [[[NEED TITLE]]]
at Agilent Technologies, Waldbronn, Germany, "instrument control
can be implemented at various levels of complexity."
As Fig. 1 shows, the level of control affects access to various
instrument parameters. It can also influence the level of meta data
collected and allows the system to comply with regulations, such
as the U.S. Food and Drug Administration (FDA) standard for making
electronic records "trustworthy and reliable." In addition,
the more advanced levels of instrument control provide diagnostics
and feedback for better instrument maintenance.
|Fig. 1: Today's research facilities, such as this networked
chemical-analysis laboratory, routinely use embedded data acquisition
systems. Courtesy Agilent Technologies, Palo Alto, Calif.
"Because data acquisition technology is closely coupled to
PC technology, the state of data acquisition art typically trails
PC art somewhat," says Joseph P. Keithley, who is simultaneously
Chairman of the Board, President and Chief Executive Officer of
Keithley Instruments in Cleveland, Ohio.
Keithley finds that a major challenge for data acquisition designers
is to accommodate the rapid changes that are so much a part of the
PC industry. While these changes have opened up opportunities, such
as web-based measurements, data acquisition cards and systems must
undergo significant design changes to take advantage of the new
"Many data acquisition and test system users resist this change,"
he observes, "particularly when they have a significant investment
in a particularly type of hardware or software."
For example, given the length of time that PCIbus computers have
been available, ISA products ought to be nearly extinct. But, many
customers continue to invest in industrial computers with ISA slots
so they can run legacy software and associated hardware that has
been thoroughly debugged. They know what works well and don't want
to invest additional time in getting a new system design to operate
"On the other hand," Keithley continues, "newbies
(those unburdened by legacy system issues) are more likely to adopt
the latest technologies and design their data acquisition or test
systems around them. From a market segmentation perspective, we
will continue to see a spectrum of users that range from early adopters
of the latest technologies to those sticking with technologies that
are two or three generations behind, all of which involve the various
Sid Mayer, President, Capital Equipment Corporation (CEC), Billerica,
Mass. notes that DAQ hardware and analog-to-digital converter technologies
are fairly mature. He feels that improvements will come mostly as
a continuation of price/performance trends and interface bus and
"This is still evolving with higher speed, higher resolution,
and low power components," Tim Ludy, Product Marketing Manager
, Data Translation, Marlboro, Mass. observes. "A good example
is Data Translation's newest USB module that has 4, 24-bit ADCs
that run independently up to just under 1,000 S/sec."
"Presently," Tim Dehne, Vice President of Engineering
at National Instrument in Austin, Tex. says, "users are selecting
vendors based on the solution that will cause the least amount of
problems for them. Flexible software, easy integration, and connectivity
between the sensors and hardware will remain key factors for data
acquisition customers when selecting components for their DAQ system."
"Software and system integration, however, still has lots
of room for improving ease of use," Mayer points out.
Ron Chapek, [[[NEED TITLE]]], IOtech, Cleveland, Ohio summarizes
the currently operating Market trends as follows:
- The ISAbus is still dominant in the industrial-automation market;
- PCIbus is dominant in the test and measurement market, with
slow trend toward adoption of CompactPCI (CPCI);
- CPCI enjoys increasing penetration into niche markets, such
as military, communication, and industrial-motion applications;
- There is a trend toward adoption of Ethernet/web-based technology,
Firewire, and USB;
- In the world of, lower-cost commodity PC-plug in boards, software
and signal conditioning have become the key product differentiators.
"Many, if not most, users are looking for easier and faster
implementation of their data acquisition systems," Keithley
observes. "To a great extent, plug-in cards are only building
blocks of a do-it-yourself systems. The builder also needs to buy
and integrate separate signal conditioners, a variety of low-level
device drivers, and other components. In today's business environment,
many users don't have the time or inclination to do this.
"They don't want to be data acquisition system designers.
They want to get on with their measurements and get their jobs done
faster. They need products that simplify the process of applying
data acquisition systems in difficult and demanding test environments,
such as those found on production and process lines. The influence
of these largely unmet demands on data acquisition product development
is growing, and probably will become dominant in the near future."
DAQ in the near future
For the next year or so, continued cost reduction, moves toward
open software standards, further development of Ethernet/web-enabled
instrumentation, and wireless data links will be the big technological
trends, according to Chapek.
Others agree. Software will certainly be a major driving force.
"Customers treat DAQ hardware as somewhat of a commodity item,"
Mayer points out, "with many vendors close in hardware features
and price. The rest of the ease-of-use equation becomes a deciding
Ludy says that the need is for application software that is easier
to use with less programming effort needed to get the users' applications
running and getting their product to market sooner.
"I see this as a year of return to pragmatism and less technology
hype," Dehne says. "Software's quality and usability will
be paramount in a user's decision on which hardware vendor is selected.
Users will gravitate to the vendor that gives them the fewest problems
with completing their DAQ applications."
Mayer sees a need for further improvement in system integration
and multi-vendor support as well: "Few applications of any
size can be completed with only a single source solution, and users
continue to find it a challenge to master multiple sets of documentation
and programming standards."
"PCs are closing up," Ludy adds, "and users will
need to replace current solutions with DAQ products that can plug
in tomorrow's personal computers."
"In the next year, National Instruments expects that the last
of the ISA users will finally transition to the PCI bus, thus taking
advantage of its higher-bandwidth and plug-and-play capability for
easier installation and use," says Dehne.
He also predicts that users will embrace the easy connectivity
offered through modern DAQ devices. Users will begin realizing the
true benefits provided by internet-based measurements. That technology
will be used commonly by engineers and scientists rather than primarily
by early adopters.
High-performance, portable solutions based on CardBUS or IEEE 1394
will deliver PCI-like performance for laptops. The market will also
expand into the higher-speed realm. Simultaneous sampling will be
a requirement of future DAQ system architectures that will operate
at sampling rates beyond 1 MS/sec.
Developers integrating larger systems that involve different measurement
devices will require very precise synchronization. They will look
to the backplane, triggering, and performance capabilities of PXI/CompactPCI
platform to meet their needs.
CEC's Mayer agrees that alternatives to plug-in cards are important
to DAQ's future: "The newer packaging and form factors, such
as USB, perhaps FireWire, and definitely Ethernet, are becoming
price competitive enough to be used in many places where plug-in
boards might have been used before."
Chapek expects eventually to see ONE architecture, such as that
shown in Fig. 2, for pilot plants, test floors, R&D labs and
production applications. "This split has been artificial,"
he says, "and the walls are coming down!"
|Fig. 2: Ethernet connectivity makes it possible to integrate
a wide variety of measurement components into a coordinated
measurement system. Courtesy IOtech, Cleveland, Ohio.
For example, Rockwell/A-B owns 50% of the large programmable logic
controller (PLC) market in North America. However, the days when
they could charge a 35% premium and supply the entire solution,
including sensors, communication protocol, PLC, I/O peripherals,
HMI, etc., as part of a closed architecture system are for the most
part over. They must now provide "best-of-breed" components
for each function. Open standards for communication protocols have
opened the door for such multi-vendor PC-based solutions.
The DAQ industry, according to Chapek, needs to move in the same
direction as the industrial-automation market. That is, DAQ vendors
must embrace open architectures, leverage commercial standards,
adopt software standards, offer Ethernet connectivity, and provide
While Chapek stated this concept clearly, it resonates with comments
made by the other experts. All seem to agree that the DAQ's future
includes a generous dose of Web technology.
"Embedded Web technology," says Mayer, "has allowed
the creation of a new type of DAQ 'appliance' that is truly plug-and-play
without software installation (for example, CEC's web-DAQ/100)."
Not only is no software required for basic operation and download
of data, but such products are inherently platform-independent,
being equally at home with Macintosh or Linux systems as well as
Windows. Off-the-shelf network technology makes it easy to route
and connect devices, and even create private wide-area-networks
with security features.
Keithley generally agrees with all these comments, but cautions
that customer demand is likely to have the greatest influence on
system features and functions, as well as the technology used to
supply them. "I believe that more manufacturers will begin
to realize that adopting the latest technology may or may not help
them get their new products to market any faster," he says.
"The key will be whether or not the technology helps quickly
create useful data collection systems. Until recently, the main
market driver has been manufacturers pushing a technology, as opposed
to customers pulling. This situation is beginning to be reversed."
Three Year Outlook
When we start looking a little bit farther out, technologies and
factors that we only hear about now should start becoming important
drivers of DAQ technology. These include:
- Increasing pressure from the regulative bodies driving the technical
implementation in regulated industries, such as pharmaceuticals.
- Independence of instrument location and the place where data
evaluation and interpretation is done.
- Instruments becoming an integral part of user companies' information
- Next generation bus technology (e.g., USB 2.0 and IEEE-1394.b)
- Sensor technology (smart sensors, MEMs, etc.) becoming feasible
in a wide range of applications.
- Wireless and wireline networking technology becoming the norm
rather than the exception.
- Leveraging of commercial devices, such as personal digital assistants
A major change that will affect DAQ-system design is the arrival
of slotless PCs. Keithley points out that manufacturers of plug-in
boards will have to react to that change by exploiting other form
factors, such as external chassis systems, if they wish to continue
supplying board-level products.
"The key feature in successful DAQ products," Mayer predicts,
"will be integration of standards for getting information from
the sensor front-end and associated electronics up to the point
Simple plug-in boards with proprietary programming interfaces will
still have market momentum from existing applications, but new applications
will demand a higher level of software capability.
"Products that rival, and in many cases exceed, the performance
of today's stand-alone products will dominate the DAQ solution landscape,"
He and Ludy both feel that the trend towards higher dynamic range
products will continue, pushing 14 and 16-bit products to higher
and higher speeds, providing more memory in the data path, and additional
signal processing power integrated into high-speed silicon.
"With the increasing power of FPGAs (field programmable gate
arrays)," Dehne says, "we will see complex triggering,
user-configurable processing, and even reconfigurable hardware make
their way into data acquisition products of the future. Sophisticated
synchronization technologies will also be available, so users can
create larger, more sophisticated DAQ systems. Finally, flexible-resolution
products that leverage advanced signal processing technology, will
emerge so users can programmatically trade speed for accuracy."
Dehne also expects DAQ systems to become more distributed. Networking
technologies, in particular wireless technologies, have the potential
to simplify the installation and maintenance of data acquisition
systems, making them accessible across a company's enterprise.
Others agree that web-enabled instrumentation will become more
common. Kraft, in fact, predicts that DAQ systems will become fully
web-enabled over the next three years. Bandwidth will expand from
10-100 Mb/sec to even higher rates via optical devices.
Expansion of web-enabled instrumentation will force the DAQ community
to develop means to provide privacy and security to instrument communication.
Kraft believes these security systems will start moving out of the
application (browser) software and into the communication protocol.
"Smart sensors are also an interesting area with a potentially
dramatic impact on DAQ systems," says Dehne. "Currently,
no global standard exists for communicating to smart sensors."
Until a universally accepted standard becomes reality, the industry
will remain fragmented and its impact on traditional data acquisition
will be limited. Another technology needed to make smart sensors
an important part of the DAQ landscape is MEMS (microelectromechanical
systems) fabrication. Using MEMS architecture, designers can pack
more functionality into a smaller real estate area. MEMS technology
can also be applied to other parts of the data acquisition process,
providing higher single-board densities and more on-board isolation
Kraft believes that analytical-instrument vendors will have to
start making shared software and communication components available
to support open systems. "Linking vendor-independent analytical
instruments together without individual engineering efforts"
will be a major unmet challenge, he says.
Mayer believes that it will be easier to combine and program a
variety of devices in an application, but real plug-and-play in
a multivendor sense will still be developing. As distributed and
interconnected DAQ systems become more common, a need will arise
for new ways to synchronize and coordinate these devices.
Looking into the Distance
Kraft makes a number of individual predictions for what the DAQ
landscape will look like five years from now:
- He predicts that the Internet will fully rule analytical DAQ
applications by then.
- Biometric devices (such as fingerprint, voice print and retinal
scans) will be integrated into DAQ for security reasons, especially
in sensitive applications, such as in the pharmaceuticals industry.
- DAQ will have more intelligence built in so that it will be
better able to operate in a client/server environment.
- DAQ systems might be operated via voice control and not via
"While it is hard to predict 5 years away exactly what products
will have as built-in features," says Mayer, "it is guaranteed
that user demands will always outstrip product features in the area
of software tools."
In addition, there will still be a need for better hardware solutions
at the most basic level of interconnecting sensors, signal conditioners,
and DAQ devices. Each vendor has some piece of the answer, but Mayer
predicts that users will still be wrestling with screw terminal
pinouts, soldering point-to-point wiring and creating special adapters.
"There is a great opportunity here for the right set of interconnect
products," he says, "but the multiplicity of vendors and
types of hardware required make this a daunting challenge."
Ease of customization and programming will have made significant
strides by then, engendering a shift in emphasis to the need to
allow end-user manipulation and reporting of results. Programmer's
jobs will have become somewhat easier, but the ever-changing demand
for new ways of viewing and crunching numbers will by no means have
disappeared, and the more of this ability can be put in non-programmer's
hands, the more successful a product will be.
The market demand for easy reporting and display will begin to
be met by the convergence of DAQ and data-mining technologies. As
DAQ devices use standards based on the Web, such as extensible markup
language (XML) or its successors, tools that come from the business
data-mining and visualization side will be applicable directly to
DAQ results by the consumers of the information.
Keithley predicts that less demanding measurements (8- to 12-bit
resolution) will increasingly become commoditized. "If the
past is any indication," he continues, "we can expect
the manufacture of such systems to move offshore. To stay in business,
domestic manufacturers will have to upgrade the value and capabilities
of their systems."
Ludy points to additional pressure that will come to bear on DAQ
manufacturers. "Products are required to pass very stringent
tests to pass FCC and CE compliance," he says, "and these
are getting more difficult to pass. For example, to pass CE tests,
our products need to be able to withstand a 4 to 8 kV transient
discharge directly to the I/O pins--and keep running!
"Today, there are many smaller companies suppling cheaper
non-compliant products. With so many components getting harder to
acquire and manufacturing lead times getting longer than some people's
careers, companies cannot afford to risk dealing with these smaller
Chapek says that companies are looking to buy from long-term partners
that reduce their short-, medium- and long-term investments. They
want risk and cost reduction. Staffs are thin and they cannot afford
to devote limited resources to protracted integration efforts or
unreliable hardware. They need to work with companies that provide
offerings that are easy to integrate, but that can also be quickly
and easily adapted to meet changing application requirements. Only
an open system architecture that can accommodate third party software
and hardware can meet these needs.
Clearly, Kraft points out, only those vendors of analytical instrumentation
who are able supply components, products or solutions which can
be linked together, and where the whole system provides more value
than the sum of all pieces, will do well.
The result, Mayer concludes, is that there will be some shakeout
of conventional DAQ vendors. Those adapting and driving the new
software tools and standards will extend their success. Others will
fall by the wayside.
"Opening up computers and configuring add-ins to do DAQ will
have become obsolete," he says. "This doesn't mean every
single such product will go away, but such devices will be clearly
the 'old way.' Such technology will not be used if at all possible."
"The most revolutionary changes in DAQ in the coming times
will be powered by the explosion of Web-based standards for information
interchange," Mayer predicts.
Kraft agrees. "While in the past instruments have been controlled
through a local user interface, and data have been collected through
A/D converters," he says, "instruments are now controlled
through the DAQ System."
This allows full documentation of method and sequence parameters
and also records any specific events, failures and instrument specific
information, such as serial numbers, for compliance reasons. It
also enables a much higher degree of automation to increase sample
throughput. TCP/IP communication also enables wireless communication,
which allows the analyst to control and monitor the measurement
process from any place. Finally, vendor-independent communication
protocols and data-file structures will allow users to mix and match
instruments and data acquisition systems from different platforms
"The infrastructure of the Web is already ubiquitous,"
Mayer observes, "fueled by conventional business applications."
Combined with recent developments in embedded-system technology,
it has become possible to cheaply put a complete web server right
near the sensors and A/D hardware--anywhere the signals may be.
In the past, a wide variety of proprietary busses and serial port
approaches have been used to cable devices together, but web technology
now makes it trivial to wire and route information across a room,
factory, or continent. A wide-area intranet can be created with
off-the-shelf components and no need for private long distance wires,
even when you want a secure connection.
Web standards go beyond the hardware connection as well. By sourcing
DAQ information directly in standard formats such as web pages,
e-mail, or FTP file transfers, there is less need to write custom
programs to consume and process the data. Developing standards,
such as XML, are paving the way for exchange of meaningful structured
data that can be pulled instantly into databases and reports without
While the "little plug-in cards" may be not long for
this world, data acquisition in the larger sense of computer-based
measurement systems is really just getting started.
Levels of Instrument Control
As specified by the U.S. Food and Drug Administration (FDA) for
research instrument systems used in the pharmaceuticals industry.
||Compliance with FDA 25 CFR Part 11 Regulations
|Level 1. Parameter set up on the instrument,
synchronization using external contacts to start and stop an
analysis, analog signal acquisition
||Start/Stop (no digital instrument control or data
||Metadata: Instrument parameters must be
Device Checks: Positive ID of sample vials may not be
available (using bar codes or BCD input)
|Level 2. Rudimentary digital instrument
control (such as a LAN, RS232 or GPIB)
||Basic instrument parameters, such as flow rate
of an HPLC pump or wavelength of an HPLC detector
||Audit Trail: Typically no instrument error
information available, require additional inspections to determine
the validity of the measurements;
Validation: Could be more difficult to support and validate
|Level 3. Full digital instrument control
(for example through a LAN, RS232, or GPIB)
||All control parameters including injector program
and method sequencing; wavelength calibration; error recording
||Audit Trail and Metadata: Full documentation
of instrument parameters used to generate a result
|Level 4. Advanced Functions
||Handshake protocol between controller and device
(provides active acknowledgment of correct receipt); self-diagnostics
and early maintenance feedback (EMF); automatic tracking of
serial and product numbers, electronic instrument logbook, supports
advanced tagging of components such as column ID tags; instrument
performs real-time data acquisition and synchronization independent
of the computer.
||Advanced error and prevention and detection; Validation:
facilitates the execution of instrument qualification and preventive
maintenance; qualifies for device checks required by the rule;
guaranteed and reproducible execution of data acquisition independent
of the current data system load (facilitates the qualification
of data integrity and traceability.)