Data Acquisition System.

The High-Speed Data Acquisition System is used for the study of radio pulsars. It is based around a high-speed instrumentation tape recorder manufactured by Datatape Inc. of Monrovia, CA, which is capable of writing at a sustained rate of 400 Mbit/s using D1-format cassettes, and a signal digitizer based on a custom VLSI chip incorporating both digital and analog components. Data acquisition system pci

The existing setup is the first version of the miniPET machine consisting of four detector modules. Each detector module consists of an 8/spl times/8 LSO scintillator crystal block, a position sensitive photomultiplier, a digitizer and digital signal processing board and an Ethernet interface board. There is no hardware coincidence detection implemented in the system, coincidence is determined based on a time stamp attached to every event by a digital CFD algorithm. The algorithm is implemented in the digital signal processing board and it generates a time stamp with a coincidence resolution of 2 to 3 ns. The data acquisition System is based on Ethernet network and is highly scalable in size and performance. Data acquisition systems

As processing capability continues to grow, signal processing systems are using ever larger amounts of sensor data in resolution, bandwidth and number of channels—to perform their functions. Data acquisition and recording systems are required that can test and support these advanced signal processors capabilities. Fortunately, the same tools and technologies that enable faster signal processing switched fabric interconnect and FPGA-based processing can also be used to implement advanced data acquisition systems for a wide range of applications, including radar. Data acquisition and control systems for flatness

The Master Control Unit (shown, upper) provides all A-D computing for the analog data collection channels of the Signal Conditioning Unit (lower), and communicates with the test cell central data-acquisition PC. The single board computer-based system uses minimal panel space of 3[.]5" x 14", or 3[.]5" of standard rack space. The Companion IIT also includes power supplies for control power, pressure transducer excitation and other data collection hardware.

A variety of switched fabrics are available with off-the-shelf support for modular data recorders. Many legacy radar data acquisition systems use RACE++, which offers up to 533 Mbytes/s per 6U VME slot. Newer systems being developed today use VITA 41 (VXS) technology to scale up to 2.5 Gbytes/s per 6U slot. VXS systems can use fabrics such as PCI Express or Serial RapidIO, or point-to-point links based on the Xilinx Aurora protocol. The choice of protocol depends on the interoperability requirements within the system and the complexity of the endpoint solution, which is typically implemented in an FPGA on each VXS card.

A data acquisition system does not need to stop with just an analog-to-digital and a digital-to-analog function. More complex systems can and do included timers, abundant digital input and digital output control lines, signal conditioning, and multiplexing.

Advanced systems such as offered by Measurement Computing Corporation, offer data acquisition system boards, cards or external devices with multiple analog-to-digital and a digital-to-analog functions. Systems are available for simple measurement and control applications to highly complex measurement and control applications requiring 100s of analog and digital inputs and outputs.

A healthy number of vendors offer IEEE 1451-compatible sensors. In addition,-many have joined with National Instruments in promoting interoperability in sensors and data acquisition platforms under the company's Sensors Plug&Play program. National Instrument's LabView application development software supports the 1451 standard, simplifying system setup and control of systems that use compatible sensors.

In many radar applications, the sensor data being recorded is converted from analog to digital outside the recorder and is transferred using high-speed fiber optic interfaces. This approach makes it easy to insert a data recorder into the system without degrading the signal integrity of the data being acquired. The data recorder typically implements a copy mode that re-broadcasts the input data, allowing the recorder to be inserted between the sensor and its signal processor without interrupting the data flow.

Due to the ever-decreasing cost of PCs and peripherals, a dedicated computer to run the data acquisition system is not a major part of your budget. Many software applications can swap data within the PC through DDE (Dynamic Data Exchange); hence systems can be built with off-the-shelf products. Because of the time savings gained by the automation and the data analysis features, the computerised measurement and control systems can pay back the investments in a short space of time.

The Acquisition and Control Processor (ACP) is VME based using WindRiver's Vxworks real time operating system. An installed IRIG-B interface card provides time stamping of sampled data. The data acquisition system is scaleable up to 1280 channels using multiple ACPs and provide scan rates varying from 10 to 160 samples per second.

For analog and mixed-mode transducers, the revised 1451.4 standard defines an interface for retrieving the digital TEDS information that is backward-compatible with legacy sensors. This compatibility ensures that 1451-compatible data acquisition systems can utilize both TEDS and legacy sensors without system modification.

There are two types of interface, shown in the figure on the opening page, both of which utilize the 1-Wire protocol from Maxim/Dallas Semiconductor for retrieving the digital TEDS data. Class 1 interfaces are used with constant-current powered sensors such as integrated electronic piezoelectric (IEPE) sensors. The interface adds digital communication in parallel with the analog sensor, allowing both types of information to share a single wire (and return) connection to the data acquisition system. This is accomplished by defining the digital signal as a negative voltage and using diodes to isolate the analog sensor or digital TEDS sections, depending on the signal line's polarity. A switch in the data acquisition system disconnects the sensor's current source and connects a negative bias voltage to the wire when communicating with the digital TEDS section.

Class 2 interfaces are used with devices that cannot tolerate an interruption in the power coming from the data acquisition system, such as a bridge-type sensor. In these devices, the interface simply adds a dedicated digital signal line and return to the sensor for communicating with the TEDS section. The digital line uses positive-voltage signaling, and both the analog and the digital signals are continuously available.

If the data acquisition system is to benefit from this capability, then signal conditioning must be able to retrieve that information. Traditional signal conditioning can be obtained from the sensor supplier or a third party. But in the case of smart sensors, the data acquisition system must have built-in calibration retrieval capability since it must read digital data from the sensor. As the trend toward smart sensors continues, the necessity for the data acquisition supplier to provide the total signal-conditioning solution will only increase.

Your Linux account will have a home directory, a set of other directories with skeleton codes that can be used to tailor them for your experiment (see section 1.3), an assigned stage area for event data, and assigned tape drive. A stage area is where your event data will be written while you are recording data. The stager component of the NSCL data acquisition system allows you to determine when data is written from this stage area on to tape. The stager also allows you to select runs to be retained or deleted after staging to tape occurs. When you are assigned a stage area, you will also be assigned a tape drive. The tape special file associated with the tape drive will be set up so that only your account can write to it for the duration of your experiment.

The STR2000 is an Automatic Data Acquisition System, which connects any of the structures range experiments to a computer and includes software to simulate structures and forces applied to them. The system consists of an interface box and software which connects experiments from the TQ structures range to a computer (computer not supplied), to enable data logging and simulation. Accepts inputs from a digital force display, a digital strain display, an angular sensor and two digital deflection indicators. This data can then be analysed using the software table and graph facilities.

Systems can acquire the needed TEDS data in one of two ways. Users can download the templates for their sensors from the manufacturer, or can use the central clearinghouse that National Instruments offers. Once the system has access to a database, it can then download the TEDS data over the network, and proceed as though the sensor itself had provided the information.

Symmetric Research' data acquisition systems provide high resolution cost effective A/D performance with easy to use PC interfaces. Sitting outside the PC, A/D's are well separated from the internal noisy digital PC environment, and feature their own clean linear power supplies for quiet operation.

CT system 12 is illustrated as simply having a data acquisition system 30. Data acquisition system 30, of course, is one of only a number of different components within a CT system. Data acquisition 30 may also include a controller 32.