Review
Just about every industry relies on data acquisition (DAQ) systems to collect critical information, from voltage and current to temperature, pressure and a whole host of other sensor-based data. This translates into a plethora of useful and interesting data acquisition (DAQ) boards, modules and systems. Here is a sampling of 2003's entries.
Addressing the need for portability, the DATAQ CF2 from Analog & Digital Peripherals (adpi.com) was billed as the market's first universal virtual instrument package and DAQ system designed for handheld, tablet, and laptop PCs. The hardware and software combo consists of a 24-bit compact flash DAQ card with 32 KB of RAM and Pocket PC test panel software. Features include six software-configurable channels that can be used for various combined functions in most custom applications.
Resolution equals accuracy in DAQ applications and DATEL (datel.com) addressed the issue with its PCI-417 parallel-sampling, PCI board that employs an independent a/d converter on each of its 32 channels to provide sampling rates up to 80 kHz per channel with a 14-bit resolution. With an aggregate sampling rate up to 5.12 MB/s, output is via two streaming 16-bit d/a channels with an output voltage range of ±2.5V at a maximum current of 5 mA and a maximum settling time of 1 µs full scale.
Going a little bit further, Dataforth's (dataforth.com) SCM9B-D100 series isolated and software configurable single-channel DAQ boards sport a 15-bit resolution. The series includes 27 models designed to convert analog input signals to digital data, with the modules transmitting data via RS-485. The modules interface directly to thermocouples, RTDs, thermistors, strain gages, voltages, currents, and timer and frequency inputs.
Becoming an emerging trend, Echotek's (echotek.com) 6U, VME64X ECAD-X-081500 exploits the power of Maxim Integrated Products' MAX108 a/d converters and programmable FPGAs to accelerate processing while taking the heat off the host processor. The a/d converters have a SFDR in excess of 55 dBFS for input IFs up to 1 GHz and sample rates from 100 MHz to 1.5 GHz. Data is output through Dual RACE++ interfaces, an LVDS output port, or the VME64X interface.
Action Instruments (actionio. com) played the speed card with its 1 kHz, 19-bit distributed I/O modules for industrial data acquisition and control applications. The modules can be configured as Modbus or ASCII protocol slaves. The series includes three distinct models: the KA1 group available in 1-, 4-, or 8-channel configurations; the KA4 group of 4- or 16-channel units with thermocouple or voltage inputs; and the KD1 group with 8- or 32-channel, multipurpose digital input units.
There have been rumors over the past year that the serial port would be supplanted by the USB. Perhaps that's true on the consumer end, but for DAQ apps, Sealevel Systems' (sealevel.com) COMM+16.PCI, PCI bus serial I/O adapter provides users with 16 RS-232 ports. Employing an XR16C850 UART, the adapter supports both standard data rates and a maximum speed up to 460.8 Kb/s. A 128-byte FIFO, claimed as 16 times larger than boards designed with 16C550 devices, is included for error-free operation in high-speed tasks.
For data acquisition applications that require high-speed memory storage capability and a Fibre cable interconnect, the CI-PCI-FC memory board from Chrislin Industries (chrislin. com) debuted as a SDRAM buffer that interfaces to the PCI Bus. The board provides memory densities ranging from 256 MB up to 2 GB and includes four Fibre optic duplex ports that support the Serial FPDP Vita 17.1 point-to-point data transport standard. In terms of speed, the 64-bit, 66-MHz PCI interface provides peak burst transfers at a rate of 528 MB/s.
—Mat Dirjish
Outlook
Rack Of DAQ, To Stay Or To Go
Without question, data acquisition applications are the quintessential backbone of the technology industry on every level. One would be foolish to predict what directions these applications will take on their own since these directions will be dictated to by the demands of every other market.
What we can expect to see is more portable products for acquisition on the go. And those large, data-logging systems that have made their home on the floors of industrial factories and laboratories are here to stay.
—MD
