Advanced DAQ Systems
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Category Archives: Resources
Identifying and Reducing Ground Loop Feedback
A Brief Introduction from CAS DataLoggers
CHESTERLAND OH—June 4, 2013
While grounding can prevent and resolve many power issues, it can also create serious issues of its own. One of the most common problems is known as ground loop feedback–often resulting when different electrical circuits are powering a system and its peripherals. This can also be a seasonal issue as hot dry temperatures can create signal noise for equipment end users, so the Application Specialists at CAS DataLoggers have put together this brief introduction to help reduce or eliminate interference issues. Read more on our White Papers page.
Cleanroom Monitoring and Alarming Using a DAQ and Control System
Delphin TopMessage Data Logger Records All Values and Provides Secure Storage
CHESTERLAND OH—January 21, 2013
CAS DataLoggers recently provided a Delphin TopMessage data logger for a Cleanroom Monitoring and Alarming application in a major hospital which needed a DAQ and control system to record extensive cleanroom measurement data including pressure, temperature, air humidity and particle counts. Users also needed the system to control the cleanroom alarm horns and ‘traffic’ lights indicating current door lock status, running on user-friendly analysis and control software which could setup a secure measurement database storing all logged values. Read more on our Data Acquisition Applications Notes page.
Capturing and Simulating Rotational and Jitter Angle-based Measurements
Capturing and simulating the high-speed rotations involved in automated machines and test rigs often plays a major role in industrial automotive applications. Common requirements are accurate speed measurement over a large range of operation, detection of speed changes, capturing jitter, jitter simulation, and angle-based data acquisition. The Applications Specialists at CAS DataLoggers have put together this article to present some practical approaches to accomplish these tasks using an ADwin data acquisition system. Read more on our White Papers page.
Automated Pendulum Demo Shows ADwin’s Microsecond Response Time
ADwin-Gold Data Acquisition System
CHESTERLAND OH—July 2, 2012
CAS DataLoggers Sales Manager Pete Martin impressed attendees with a unique ADwin demonstration at a successful exhibition at the 2012 Control System Integrators Association (CSIA) Executive Conference in Scottsdale, Arizona. This demo utilizes an interesting program highlighting how to achieve microsecond response times with a measurement and control system while operating in the Microsoft Windows environment, employing an inverted pendulum, which is highly unstable unlike the balance of a regular pendulum. Read more on our White Papers page.
R&D Testing for Calcium Treatment Water Filters
Delphin TopMessage Modular Data Acquisition System
CHESTERLAND OH—February 15, 2012
CAS DataLoggers recently supplied the data acquisition solution for a customer specializing in providing water purification filter systems and cartridges for industrial and household applications. These filter cartridges were widely used to improve water quality and taste, especially for coffee vending machines but including even large industrial plants. The filter material acted to reduce the water’s calcium content, balancing its pH level and binding other metallic ions. The filter granule material itself was developed in the customer’s R&D lab for each specific filter and purification treatment application individually, where they needed to be tested to gauge their effectiveness on water consumption. Read the entire article on our white papers page.
Cold Atom Quantum Physics Experiment
Utilizing Modular Real Time Data Acquisition and Control
CHESTERLAND OH—December 7, 2011
CAS DataLoggers recently provided the data acquisition and control solution for an associate professor of physics at a major university running an experiment producing ultracold quantum gases containing either bosons or fermions. The experiment took place under ultra-high vacuum inside a pyrex glass cell. Researchers collected the atoms in a magneto-optical trap (MOT) which consisted of 6 laser beams for each atomic species and a magnetic trap produced by two external coils with counter propagating current. While the MOT was on, bright purple LEDs caused light-assisted desorption of atoms from the walls of the cell so that they could be captured in the MOT. After a brief moment of optical molasses (with the lasers on but no magnetic field), the atoms were gently transported vertically about 5 cm to within 200 μm of a magnetic chip trap by changing the shape of the magnetic field with more coils. Current passing through a wire on the chip, along with external coils, was used to tightly trap the atoms. Radio frequency signals passed through another wire on the chip, which changed the shape of the trap and allowed the hottest atoms to escape, thus lowering the average energy of the atoms. This evaporative cooling could produce quantum degenerate gases, either Bose-Einstein condensates or degenerate fermions. To undertake this incredibly demanding application, the physics department needed a modular data acquisition system capable of highly-accurate measurements in real-time and which offered intuitive software with powerful graphing and display capabilities.
The research team installed an ADwin-Pro Modular Real Time Data Acquisition and Control System to provide them with precise timing and deterministic control of the experiment’s processes. The ADwin system’s analog channels were used to control current in the coils or wires on the chip and the frequencies and amplitudes of the lasers. The analog output was programmed to step, ramp, or follow an S-shaped curve as desired. Easy programming of the ADwin Pro’s analog channels provided a simple way to control many devices in the lab. The digital channels were used to open shutters, trigger frequency sources, flip polarity of current sources, and trigger cameras. Several digital channels were also used to serially program frequency sources. Signals from the digital channels went to a digital buffer consisting of optical isolators to prevent ground loops from forming in the system.
For some experiments, the researchers chose to transfer these cold atoms from the magnetic chip trap to an optical dipole trap – crossed laser beams which caught the atoms as the chip trap was turned off. This purely optical trap gave experimenters the freedom to adjust the external magnetic field as they pleased, giving them the ability to address Feshbach resonances and to tune the interactions between the atoms. To image the atoms at the end of an experiment, the trap was turned off, the cloud expanded, and a pulse of laser light cast a shadow of the atoms onto a CCD camera. From the size, shape and density of the shadow, the team could determine the cloud’s physical properties.
Every aspect of this experiment required the precise control provided by the ADwin-Pro system. Voltage controlled acousto-optical modulators altered the frequency and amplitude of the laser light, while seven external coils as well as wires on the chip created the magnetic field. The way these magnetic fields switched on and off were important to keep the atoms cold. The team used voltage-controlled power supplies to control the current through these coils and wires. Other equipment including radio and microwave frequency sources, shutters and cameras required well-timed triggers.
By means of the configurable ADTools software, researchers were able to display the experiment’s real-time data graphically or numerically, to visualize process sequencings, or to set input values via potentiometers, sliders or push buttons. Additionally, ADtools constantly provided researchers with the current status of their ADwin system resources. The ADwin software environment could be used under Windows (2000/XP/Vista/Win7) and Linux, or as a stand-alone data acquisition system. Also, ADwin offered drivers for many of the popular programming environments including Visual Basic, Visual C/C++, LabVIEW/LabWindows, TestPoint and others.
The university’s physics department benefitted in several ways following installation of the ADwin-Pro Modular Real Time Data Acquisition and Control System. Using up to 480 analog/digital I/O inputs and high-performance DSP processor, the ADwin-Pro system performed real-time measurements at extremely high accuracy and also performed all the necessary control functions for the experiment. The system’s modular design offered researchers the flexibility to configure the cards as desired and to add more hardware as needed. Additionally, ADwin’s intuitive ADbasic and ADTools software added visualization, graphing and display features and ensured that the experiment continued uninterrupted with continual status of system resources.
Check out the Adwin-Pro product page here.
For further information on the ADwin-Pro Modular Real Time Data Acquisition and Control System, other data acquisition devices from ADwin, or to find the ideal solution for your application-specific needs, contact a CAS Data Logger Applications Specialist at (800) 956-4437 or visit the website at www.DataLoggerInc.com.
Contact Information:
CAS DataLoggers, Inc.
12628 Chillicothe Road
Chesterland, Ohio 44026
(440) 729-2570
(800) 956-4437
sales@dataloggerinc.com
http://www.dataloggerinc.com
Measuring and Sending Analog Sensor Data via the CANbus
ADwin Data Acquisition and Control
CHESTERLAND OH—November 16, 2011
In automotive or other vehicle applications, it’s often desirable to read data from one or more sensors providing an analog voltage output and to transmit this data via the CANbus; this way it can be read along with other data being broadcast by an ECU by a single data logging device. ADwin data acquisition systems provide an ideal platform to implement a simple solution for this. These stand-alone real-time data acquisition and control systems feature analog, digital, CANbus, and Serial I/O for use in research, manufacturing, test stand, aerospace and automotive applications.
Figure 1 shows a basic flow chart for a program to read and output data.
ADwin data acquisition and control systems are available in several different models with different analog input capabilities, but they are all suitable for this application when outfitted with the CANbus interface option. The flexibility of the open programming environment of ADwin systems makes it especially easy to read and scale the data. High level functions and built-in message structures allow the generation and transmission of CAN messages with just a few simple statements.
The ADwin operating system is an event-based environment which allows periodic message generation without the need for special timing routines. In the example below, the GLOBALDELAY statement sets the event loop to execute every millisecond to read and transmit the data. In this example the data is being broadcast, but it is quite easy to configure the system to use polled message transmission. In this case, the CAN interface can be configured to look for a particular message ID and generate an interrupt to trigger the event loop and send the data.
Other powerful features of the ADwin systems are the built-in high level functions and their ability to freely program calculations with very little overhead. In the example below, it is obvious how easy it is to read the A/D converter; a single instruction returns the current input value. Likewise, scaling calculations can be done with a single, intuitive equation. These capabilities enable more complex operations such as averaging, filtering, and statistical operations. Internal routines which handle casting operations make it easy to manipulate integer, floating point and binary data transparently.
The ADwin architecture provides for transparent shared data between the internal operating environment of the ADwin system and an attached PC. For debugging, this greatly simplifies monitoring the values of variable via the PAR (integer) and FPAR (floating point) shared data. The environment also provides for data arrays to enable charting and logging.
The following sample program is for an ADwin-Pro system with a Pro-Ain-32/16, 16 bit analog input card and a Pro-CAN-2, 2 channel high speed CAN interface card.
#INCLUDE ADwinPRO_ALL.inc
‘* ADWIN-PRO MODULE ADDRESS DEFINITIONS
#DEFINE modAIN32_16 1 ‘Define address of analog input module
#DEFINE modCAN2 1 ‘Define address of CAN interface module
#DEFINE CAN_CH1 1 ‘Define CAN channel
‘* DEFINITION OF PAR VALUES
#DEFINE RAW_ADC PAR_1 ‘Temporary variable for raw A/D conversion
‘* DEFINITION OF FPAR VALUES
#DEFINE OFFSET FPAR_1 ‘Sensor zero offset for engineering units
#DEFINE GAIN FPAR_2 ‘Sensor gain for engineering units
#DEFINE SCALE FPAR_3 ‘Scale factor for CAN message
#DEFINE PRESSURE FPAR_4 ‘Sensor value in engineering units
DIM CANDATA AS LONG ‘Sensor value for CAN message
INIT:
GLOBALDELAY = 40000 ‘Update rate in ticks = 1 msec.
INIT_CAN(modCAN2, CAN_CH1) ‘* Initialize CAN Controller
FPAR_2 = SET_CAN_BAUDRATE(modCAN2, CAN_CH1, 250000) ‘For J1939=350 kBit
‘PGN 65263 is for oil pressure, send as J1939, 29 bit identifier of 018FEEF
EN_TRANSMIT(modCAN2, CAN_CH1, 1, 018FEEF00h, 1)
GAIN = 100.0 ‘0-10V out is 0-100 PSI
OFFSET = 0.0 ‘default offset is 0 PSI
SCALE = 4.0 ‘Std. scale factor for message is 4
EVENT:
‘ Read ADC, convert counts to pressure and scale based on CAN std.
RAW_ADC=ADC(modAIN32_16,2)
PRESSURE = (((RAW_ADC – 32767)/32767)* GAIN) – OFFSET
CANDATA = PRESSURE * SCALE
PAR_2 = CANDATA ‘Debug
‘ Build CAN Message – pressure is in byte 4 so pad leading bytes with FF
CAN_MSG[1] = 0FFh
CAN_MSG[2] = 0FFh
CAN_MSG[3] = 0FFh
CAN_MSG[4]= CANDATA ‘ BYTE 4 = ENGINE OIL PRESSURE
CAN_MSG[5] = 0FFh ‘ Add trailing pad byte
CAN_MSG[9] = 6 ‘ message length is 6 bytes
‘Send message
TRANSMIT(modCAN2, CAN_CH1, 1)
END:
For further information on the ADwin data acquisition and control systems, other data acquisition devices , or to find the ideal solution for your application-specific needs, contact a CAS Data Logger Applications Specialist at (800) 956-4437 or visit the website at www.DataLoggerInc.com.
Contact Information:
CAS DataLoggers, Inc.
12628 Chillicothe Road
Chesterland, Ohio 44026
(440) 729-2570
(800) 956-4437
sales@dataloggerinc.com
http://www.dataloggerinc.com
CAS Releases New Data Acquisition Video
Spotlighting ADwin Real-Time Data Acquisition and Control Systems
CHESTERLAND OH—October 12, 2011
CAS DataLoggers has released its latest video showcasing the capabilities and specifications of its powerful ADwin data acquisition and control devices in inventory. Posted on YouTube, this detailed walkthrough outlines the basics of ADwin system architecture, popular products, relevant applications, and software features. The 3-minute video can be found on YouTube here. Viewers can also subscribe to the CAS DataLoggers YouTube channel here to view additional manufacturer videos and get a first look at the industry’s latest solutions. Near the end of the video is a catalog page listing additional datalogging manufacturers distributed by CAS.
ADwin data acquisition systems support parallel, individually-controlled, real-time processes while running independently of the PC’s operating system but sharing data. These devices feature a local DSP controller, an optional TiCo coprocessor, and tightly coupled analog and digital inputs along with counters providing extremely low latency operation. These sophisticated devices feature deterministic real-time operation with a response time measured in useconds, stand alone operation, and interface with all popular PC programming tools. Additionally, ADwin systems are freely programmable.
The hardware solutions displayed in the video are suitable for a wide variety of applications and project requirements. The ADwin-Light-16 intelligent real-time data acquisition and control system features 8 analog inputs, 2 analog outputs, 6 digital inputs and outputs, a 100kHz sample rate, and a local 32-bit SHARC DSP. These systems are ideal, low-priced solutions for fast data acquisition and control running in real time under Windows. For more demanding applications, ADwin-Gold-II systems offer 16 analog inputs, up to 8 analog outputs, 32 digital I/Os, a 100kHz sample rate, and an optional TICO co-processor. The device also features Ethernet or USB interface for communication with a PC and is housed in a robust metal enclosure for use in industrial applications or in the field. For users requiring modular real-time data acquisition and control, the powerful ADwin-Pro-II system contains up to 480 analog inputs, digital inputs and outputs or any combination of these. Additionally, a high performance 300 MHz DSP processor and an Ethernet communications interface are also included as well as an optional TICO co-processor modules for local pre-processing. This flexible, expandable system is offered in a variety of enclosure sizes, modular configurations, and in both AC and DC powered versions.
The broad range of applications for ADwin systems include test stand control and data collection, component testing, equipment control, servo-hydraulic systems, laser and Ebeam control, and automotive test. These high-speed data acquisition devices are also used for automation, open and closed loop control, intelligent data acquisition, signal generation and digital communications in research, manufacturing and test labs in automotive, aerospace, physics and military facilities.
ADwin systems offer the popular ADbasic software as the solution for flexible and simple programming of fast data acquisition, open-loop and closed-loop control procedures. ADbasic programs are executed on the local processor of the ADwin hardware, triggered by the occurrence of an event signal. With ADbasic, users create the processing procedures based on the ADwin running system. The program code is optimized and compiled over ADbasic or a PC user interface in the ADwin system loaded and run from there independently. The commands for measurement and control functions and floating-point operations are already in the instruction set of ADbasic integrated. A library of functions, such as filters, and numerous examples for counters, regulators, function generators, etc. help users quickly build their programs.
Other software options are also available: with the quickly configurable ADtools utility software, users can display their data graphically or numerically, process visualizing patterns, make inputs via potentiometers, sliders or buttons, and the ADwin control system resources. ADlog data recording software turns the user’s system into a datalogger for recording, visualizing and evaluation of large data amounts without programming effort. Matlab/Simulink graphical programming is also supported. The ADwin software environment can be used under Windows (95/98/ME/NT/2000/XP/Windows 7) and LINUX or as a stand-alone data acquisition system. Also, ADwin has drivers for many of the popular programming environments including VB, VC/C++, LabVIEW, TestPoint and others.
Bing Brown, CAS Data Acquisition Product Manager, commented: “Our cost-effective ADwin systems regularly handle the most demanding data acquisition and control projects. No matter what the size of your project, these advanced solutions have the precision and software analysis capabilities to handle it.”
Check out the ADwin product overview page here, and the CAS inventory of data acquisition and control systems here.
For further information on ADwin data acquisition and control systems, other data acquisition devices, or to find the ideal solution for your application-specific needs, contact a CAS Data Logger Applications Specialist at (800) 956-4437 or visit the website at www.DataLoggerInc.com.
Contact Information:
CAS DataLoggers, Inc.
12628 Chillicothe Road
Chesterland, Ohio 44026
(440) 729-2570
(800) 956-4437
sales@dataloggerinc.com
http://www.dataloggerinc.com
How to Select a Portable Data Acquisition System
Choosing the Ideal Solution for Any Application
CHESTERLAND OH—September 13, 2011
Portable data acquisition systems are used worldwide to capture data and conduct routine testing of vital infrastructures such as mass transit systems, power grids, and bridges, as well as heavy industrial processes and applications. These powerful yet compact data acquisition devices play an important role in the testing and monitoring of many critical systems, and selecting the most suitable device for a given application requires careful consideration. The ideal portable data acquisition system for most users is a compact, lightweight unit powered by either a self-contained battery or a single DC power source, requiring no other connection to function other than the sensors being monitored. Operating in remote areas, a user interface and means of communication with the device become vital features. Signal conditioning such as gain and filtering as well as high-capacity non-volatile data storage are other important considerations.
When selecting a suitable portable data acquisition system for their specific applications, users face a bewildering choice of available manufacturers, models and specifications. Each system has its own configurations that make some units more suitable than others for certain applications. Additionally, purchasers must first consider several demanding requirements not necessary for traditional laboratory devices. Any existing and potentially damaging environmental extremes including temperature, excessive humidity, liquids, dust, shock and vibration should be carefully considered. Other relevant questions to ask include whether the data acquisition equipment can support the particular mix of sensors that will be used, as well as determining if the device has adequate memory and storage to support the specific project.
Before deciding on a specific manufacturer or solution, users need to form a clear idea of the results they require of any system they’ll be using. Sampling rates, as just one factor, are available in a wide variety from as low as once per day to higher than a million per second. Anticipating the future project’s needs today will save precious time and money on installation. Data acquisition system designs range from the simple to the complex, with an attendant variety in performance, features, and cost. Fortunately, in the face of all these options, fundamental guidelines are available for portable data acquisition equipment users to consider before making their purchase.
Of course, the main function of data acquisition systems are their basic function to accurately record data, and here the wide spectrum of degrees of accuracy attainable by units available on the market can make this a more involved decision than expected. A reliable constant, though, is that the accuracy of field measurements is heavily based upon the sensors being used. For most sensors that have been calibrated in the laboratory and installed in the field, accuracies in the range of 0.01 % to 1 % of full scale are typical, with many other sensors having less accuracy. The particular system’s input types must also match project requirements–for example, an application requiring extensive analog measurements would benefit from the portable Delphin Expert Key 200 series of data acquisition system, which features a full 28 analog inputs.
Likewise, the sampling speed of DAQ systems must also be taken into account when determining accuracy. The device must acquire signals quickly enough to avoid any loss of the data. The necessary data acquisition speed is calculated by using Nyquist’s Sampling Theorem, which states that a signal must be sampled at twice the frequency of the spectral signal components which are of interest in order to accurately reconstruct the waveform. The Delphin Expert Key 200 series mentioned above has a 100kHz maximum sample rate.
Also vital to many users’ considerations are the environmental conditions which the device will be subject to. Portable data acquisition equipment is naturally susceptible to damaging environments, such that ruggedized packaging of the DAQ unit itself, as well as its electrical components, is an essential manufactured precaution to ensure both device and data integrity. For example, portable DAQ equipment used in heavy industrial applications often needs to withstand a broad temperature range. In the absence of ruggedized models, a portable enclosure may give adequate protection for the system. In these harsh environments, and to retain their portability, DAQ systems need to be as compact and lightweight as possible. Further, beyond withstanding these environmental extremes, portable data acquisition units need to be able to survive in high shock and vibration environments such as the trunk of a car or onboard an airplane, or just as a result of the occasional accident such as being dropped by its owner. Other sealing and packaging precautions such as watertight housing should be under review for aquatic applications such as flow rate measurement and wastewater monitoring which partially or completely immerse the device.
For remote applications where access to a standard 120V AC power outlet isn’t available, electric power to the system can be provided either through an internal battery pack, or the user can connect an external wire to a DC power supply. Additionally, in order to conserve power and avoid unnecessary processor loadup, users with minimal processing requirements can select a lower performance CPU and rely on a capable storage system.
When analyzing recorded data and exporting to other formats, many users rate software primarily by how user-friendly it is, which often depends on graphical interface style, menu navigation and help tips. Continuing with the earlier example, the Delphin Expert Key 200 series features ProfiSignal software for data storage, display and analysis.
Choosing a portable data acquisition system featuring internal signal conditioning capabilities can greatly improve system quality and performance. Different types of signal conditioning include amplification, attenuation, and filtering. As always, the specific application involved and the types of sensors used to make the measurements will decide the type of signal conditioning required—to measure temperature, a device will probably need to use thermocouples or thermistors. Thermocouples produce a voltage that varies with the temperature, but connecting a thermocouple to a data acquisition system creates a cold junction point at the terminals that acts as a thermocouple itself. Signal conditioning is required to compensate for this, or else the recorded temperature which is taken from the total voltage will be altered by the additional voltage of the cold junction point. Signal conditioning can also be used for signal amplification to mitigate any noise distortion, and is also useful when a DAQ device is connected to other transducers such as strain gauges, accelerometers, etc.
When designed to monitor remote unattended systems, suitable DAQ devices have communications capabilities utilizing telephone connections or wireless systems to download data to remote PCs. They also require ample built-in storage and user interfaces to enable setup and control. Advanced solutions use built-in testing capabilities allowing users to sit back as the system acquires the data.
Taking into account all these specifications when choosing the right portable DAQ device is certainly an involved process, but one made easier by always keeping the needs of the present and any future applications foremost in mind. Check out the Delphin Expert Key Data Acquisition System product page here.
For further information on the Delphin Expert Key 100-200 series of portable data acquisition devices, other Delphin data acquisition devices, or to find the ideal solution for your application-specific needs, contact a CAS Data Logger Applications Analyst at (800) 956-4437 or visit the website at www.DataLoggerInc.com.
Contact Information:
CAS DataLoggers, Inc.
12628 Chillicothe Road
Chesterland, Ohio 44026
(440) 729-2570
(800) 956-4437
sales@dataloggerinc.com
http://www.dataloggerinc.com