Your new assignment to find the right recorder for your application using the latest technologies keeps you tossing and turning all night. Then you wake up and are relieved to discover what you need is readily available. The latest generation of recorders and dataloggers has experienced the same technological rush as laptops, storage scopes, and printers.
“Our new datalogger,” said Steve Lekas, vice president of new products at IOtech, “is the size of a notebook PC and can go anywhere. It offers a high sampling rate and high channel capacity.”
No more do you have to compromise features for availability. Today’s recorders are smaller, smarter, and easier to use. They offer very fast/slow event capture, direct hard copy, a rugged package, battery operation, lots of channels, high-speed transient storage, serial communications, remote sensing, network operation, or all of these.
Customers want accuracy, flexibility, affordability, connectivity, and ease of use, according to Barry Scott, product manager of Hewlett-Packard. The accuracy norm now is 16 bits instead of 12, and the PC has become a ubiquitous tool for analysis and storage.
“Customers want a low-cost, complete measurement solution,” added Fred Glow, market research manager of Keithley. “They want lab-quality measurements and compatibility of components such as plug-and-play.”
Will a straight analog chart recorder do the job? These stand-alone units are relatively inexpensive and easy to use and interpret and do not require software/computer intervention. One type, the galvanometer chart recorder,
handles frequencies from DC to 150 Hz, and multichannel traces may be distinguished via colored pens.
Another analog recording technology is magnetic tape, which is used in audio and video cassettes. Tape as a storage medium is low cost and has high storage capacity, high bandwidth, and flexibility for both analog and digital recording techniques. Common tape recording media are digital audio tape (DAT), VHS, and S-VHS with bandwidths to 90 kHz.
Digital recording technology is usable with paper drives, tape drives, disk drives, and semiconductor memories. The bandwidth-limiting factor is the analog-to-digital converter (ADC), which may run at 250 kHz. For 10 samples per analog frequency cycle, the ADC will perform to 25 kHz.
In either analog or digital systems, the bandwidth is divided by the number of channels if they are multiplexed or time-shared. For example, if the system bandwidth is 80 kHz and there are eight channels, the aggregate throughput rate is 10 kHz.
Thermal array recorders go to 25 kHz. With these recorders, “paper output is a valuable, unfiltered analysis tool,” pointed out John Lauletta, vice president of sales and marketing at Gould. “It provides an immediate critical review mechanism for the results of a test.”
PC architecture now is being put to use for recording purposes. “PCs are inexpensive,” indicated Byron McIntire, president of Soltec. “Chart recorders and dataloggers implement PC architecture to give users familiar interfaces, strong software support, and compatibility among manufacturers.”
A class of embedded PC recorders streams data directly to disk. This eliminates interim storage and transfer and takes advantage of a high-capacity, low-cost storage medium.
Many recorders now have built-in or plug-in signal conditioning to interface with common sensors. Signal processing circuits, both analog and digital, are getting smaller, faster, and more accurate and reliable. The increasing role of digital signal processing (DSP) also is more evident in the many math and statistical-type functions that are offered.
Today’s small PC card memories store up to 520 MB and consume little power. This is revolutionizing field and lab instruments alike. The unit that once sat on a desktop now fits in your hand and is battery operated.
Once data is stored in digital memory, PC hardware and software technology becomes available. The graphical, no programming capability to develop software is leading the charge in propelling today’s instruments toward key roles in automation and networking applications.
“Networking allows dataloggers to handle many applications for on-site, real-time analysis of data,” says Bruce Fuller, product manager of Fluke Data Acquisition Group. “Connections to local area networks enable multiple users to view data instantly, anywhere.”
Issues such as speed, accuracy, the number of channels, signal conditioning, memory capacity, memory access, software, environment, and reliability must be taken into account in the selection of a recorder. Environmental issues include, ruggedness, operating temperature range, and protection from vibration, shock, and radiation. For reliability, users need to know if the recorder has a sufficiently long mean-time-between-failure specification..
Some things are given: Only a recorder with paper can give hard copy without outside intervention, and only a semiconductor memory has no moving parts. The key issues for a straight semiconductor (nonrotating) memory still are capacity, volatility, and cost per bit. Follow these issues until you decide which recording technology best suits your application.
And don’t forget practicality. “Business survival means doing more with less, commented Frank Banta, product line manager, T&M Recorders at Yokogawa. Waste is eliminated with quality analysis of data. We allow you to spend less time acquiring data and more time making decisions.”
The Integra 15 Digital Storage Oscilloscope has four differential input channels, a 12-bit digitizer, and a color display. It provides direct-to-hard-disk recording speeds of up to 100 kS/s for up to 40 minutes. Accuracies are better than 0.25%. The display simulates a chart recorder, and there is one-touch hard copy to a printer. Math functions are built-in. Windows-based software provides IEEE 488 control, analysis, and report generation. From $9,990. Nicolet Instrument Technologies, (608) 276-5600.
Has Six Channels
The Data-Chart® 3600 Paperless Recorder has six isolated analog inputs and displays up to 12 channels of information on a 5″ LCD. It accepts inputs including DC voltages and currents, thermocouples, RTDs, and pulse signals. Touch-screen control facilitates selection of scale factors and analysis functions. Data is stored on an internal 128k buffer and on a PCMCIA card or a floppy disk. The recorder computes multiple math functions, provides 60 alarms, and conforms to the CE Directive. Starts at $1,995. Monarch Instrument, (603) 883-3390.
Recorder Stores Data
On PCMCIA Card
The Model 510 T-Corder records eight analog channels with 10-bit accuracy and stores them, relative to the built-in real-time clock, on a removable PCMCIA memory card. It recognizes and handles signals such as voltage, temperature, pressure, strain, rotational speed, pulse counts, and switch positions. The recorder may be operated in a stand-alone mode or while connected to a host PC using included software. From $1,495. Vulcan Enterprises (602) 759-1600.
Light Recorder Offers
Many Plug-In Modules
The DC100 Data Collector has 10 to 40 input channels, a variety of plug-in modules, a 1-MB nonvolatile RAM, a multiline display, an editing keypad, and a floppy disk drive. Up to four modules can be installed in its slots, allowing you to configure and modify input/output to your application. All channels are scanned in 0.5 s. Captured data is convertible to ASCII for import into standard spreadsheet programs with no intermediate software. Optional SCSI or Ethernet interfaces facilitate data transfer or networking via a PC. From $2,450. Yokogawa Corp. of America, (770) 251-8700.
The SnapShock-PLUS Series records peak shock levels, duration, and date/time of transient acceleration events. The recorders feature a single or tri-axial accelerometer; signal conditioning with user-selectable filtering; 12-bit, 1,200-Hz digitization; nonvolatile storage for up to 5,900 readings; and a real-time clock. Data is fed using an RS-232 interface to a PC. It comes with Windows 95-based software for data recovery and analysis. One axis: $1,800; three axes: $3,750. Instrumented Sensor Technology, (517) 349-8487.
The GageStream 10 Data Acquisition/Recording System consists of a CompuScope 8012A/PCI 12-bit A/D PCI-bus computer card powered by a Pentium CPU, a high-speed SCSI controller, and a 4-GB SCSI disk drive. A high-speed FIFO streams data to the SCSI disk at 5 MS/s. The system comes in single- or dual-channel configurations with trigger facilities and a 15″ display. Windows 95™-based software sets operating parameters. Captured data is accessible from third-party analysis programs such as MATLAB. $14,995. Gage Applied Sciences, (800) 567-4243.
Thermal Recorder Has
The VIPER TA is a thermal recorder with a 30-kHz bandwidth, 14-bit resolution and 16-Mword memory. Features include a 10.4″ color LCD with on-screen zoom and cursor controls and a 270-mm paper output to 200-mm/s. The sampling rate is 250 kHz. There are four, eight, or 16 channels, each with signal conditioning, a programmable gain amplifier, and a programmable filter. Standard PC interfaces are RS-232, a mouse, a keyboard, and VGA. From $11,995. Gould Instrument Systems, (216) 328-7000.
Logger Is Networkable
The KNM-RTD32 is a signal-conditioning SmartLink™ Temperature Monitor for up to eight single-ended or four 4-wire RTDs. A 20-bit ADC delivers seven readings/s. Memory stores 10,000 8-bit readings or 5,000 16-bit readings. The KNM-RTD32 connects to a PC using an RS-232/422/485 or the Universal Serial Bus. Interfaces are available for linking to modems and PCMCIA. Windows-based software is included. From $995. Keithley Instruments, (888) 534-8453.
Hand-Held Logger Features
Multisite Transducer Inputs
The ASC Hand-Held Data Acquisition Terminal offers communications and processing capabilities for data entry, monitoring, and datalogging. It features multiple transducer inputs and a manual keyboard with an alphanumeric display. Up to eight analog and eight digital input signals can be applied. Optional accessories include a portable printer, a tape recorder, a bar-code reader, and a magnetic card reader. From $990. ASC Systems, (313) 882-1133.
Series Is Datalogger
The HP 34970A Switching Multimeter offers 11 measurements with internal signal conditioning. You can set scale factors, alarm limits, and measurement functions for each channel. The stand-alone instrument features 50,000 readings of nonvolatile memory. It includes Microsoft Windows 3.1-, 95- and NT-compatible Benchlink Data Logger Software to configure, display, analyze, and archive data on a PC. Three slots accept any of eight add-in switch and control modules. From $1,685. Hewlett-Packard, (800) 452-4844, ext. 5089.
Has Six Channels
The MMS3000™ T6V4 is an MMS3000 Hand-Held Datalogger with a T6V4 plug -and-play module that measures and records six channels in any combination of six thermocouples and four voltages. Data is stored in 128 kB of nonvolatile memory of about 100,000 samples and displayed on a graphical display screen. Resolution is 0.1°. Windows-based software allows the unit to be programmed from a serial port. A battery pack and a built-in charger are included in the 3-lb unit. $995. Commtest Instruments USA, (805) 273-6597.
Doubles as Calibrator
The Fluke 2635T Recording Thermometer comes with a precision platinum RTD probe and is calibrated to 0.015°C single-point accuracy. It has a 21-channel input connection that accepts thermocouples, RTDs, AC/DC V, frequency, ohms, and current and calibrates 18 thermocouples simultaneously. Circuit isolation supports measurement to 300-V AC rms and 1,500-V surge. The unit stands alone and conforms to CE standards. A removable 256kB PCMCIA card adds storage. Optional Windows-based software does not require programming. DC accuracy is 0.018%. RS-232 and IEEE 488 interfaces are included. $4,490. Fluke, (800) 443-5853.
Has DSP Filtering
The Dash 8u is an eight-channel, 20-lb field recorder featuring a 10.4″ color LCD, an internal 2-GB hard drive, DSP-based filtering, and a 100-MB removable zip drive. The input range extends from 50 mV to 500 V peak. It records voltage, current, temperature, strain, and pressure gage signals. It displays and records eight channels of data at frequencies up to 2 kHz. Z-fold chart is 8.5″ wide with speeds from 1-mm/h to 100-mm/s. Ethernet interface is built-in. Optional Windows software transfers data to a PC. $10,995. Astro-Med, (800) 343-4039.
The TA220-3608 Digital Oscillographic Recorder with real-time, memory, data-storage, and transient modes provides a sample rate of 200 kHz. It has eight slots to accommodate signal-conditioning modules. A 2-Mword memory has flexible allocation, typically 256k × eight channels. The maximum chart speed is 200 mm/s. Features include a 10.4″ color LCD touchscreen, a soft-key control panel, a floppy disk drive, and RS-232, IEEE 488, and SCSI interfaces. A DC-powered chassis (11 to 28 VDC) is available. From $9,725. Soltec, (800) 423-2344.
Data Acquisition System
Runs on DC Power
The LogBook/300 Data Acquisition System is powered by 10 to 45 VDC with a 90 to 240 VAC adapter. The 16-bit ADC runs at 100 kHz, and the system operates with 16 inputs with plug-ins to 256 analog and 208 digital channels. A required PC-card memory ranges from 12 MB to 520 MB. An internal 4-MB RAM and LogVIEW™ software are included. Data upload to PC is by way of serial or parallel port. A hand-held terminal option contains a soft-key pad and a display. From $3,495. IOtech, (440) 439-4091.
The NOMAD™-T Datalogger measures and records temperature using an internal sensor from -40° to 70°C. An optional remote sensor covers from -40°C to 123°C. A two-year battery life, an LED indicator, and programmable limit alarms are among the features. Nonvolatile memory of 8k, 16k, or 32k is available. Optional software for DOS, Windows, and Macintosh uploads data to a computer and is spreadsheet-compatible. The Windows and Macintosh programs provide graphic display and printout capability. From $135. Omega Engineering, (203) 359-1660.
With Many Sensors
The Mini-Log B, a combination datalogger and indicator, is battery-powered and equipped with variable sensor connections for 0/4 to 20 mA, 0 to 1 V, or PT100. With an appropriate sensor, the unit records temperature, humidity, pressure, flow, or level. The instrument becomes an analysis tool using an RS-232 interface and optional software. From $330. Endress+Hauser, (800) 428-4344.
Acquisition System Has
80-kHz Throughput Rate
The µ-Musycs Recorder offers 64 channels, dual time-base storage, an internal PCMCIA memory, and Ethernet and RS-232 connections. Features include a 2-MB memory and an aggregate digitizing/throughput rate of 80 kHz with 32 analog inputs, 32 digital I/O ports, four incremental encoder inputs, three accelerometer inputs, and eight analog outputs. It has built-in signal conditioning for thermocouples, strain gages, and opto-isolated digital data. Software for Windows provides visualizations, on-line reports, and post-processing calculations. From $7,800. Hi-Techniques, (800) 248-1633.
Data Acquisition System
Processes Analog Signals
The Model 10KU-EL Data Acquisition/Logger with up to 24 analog inputs includes a mainframe, a display, a calculator-like control panel, Windows-compatible software, a 16-bit ADC, an RS-232 interface, a logic I/O card, and a choice of 27 analog signal-conditioning cards. Each input channel has an amplifier, a three-pole filter, and selectable digital smoothing. Accuracy is to 0.02% of full scale, following calibration. This stand-alone unit provides information to the computer on demand. No programming is required. $2,195. Daytronic, (937) 866-3300.
The A480 Instrumentation Recorder accommodates 24 channels at DC to 25 kHz for two hours. The tape cassette stores 25 GB, and the dynamic range is 90 dB. There are I/O modules for data, voice, and IRIG A, B, or G time code. Signal- conditioning modules accommodate ICP™, microphone, strain gauge, accelerometer, and digital inputs. Up to seven A480 recorders may be interconnected, fully synchronized, for 336-channel capacity. Standard interfaces are SCSI and RS-232/422. Racal Recorders, (800) 553-8279.
250-kHz Sampling Rate
The WR8500 Recorder features an 8.9-inch LCD, chart speeds to 200 mm/s, eight or 16 inputs, and a sampling rate of 250 kHz. In the recorder mode, analog signals are displayed as waveforms, and data is stored in memory. In the memory recorder mode, data captured to memory is displayed as waveforms. In the logger mode, data is recorded and displayed as digital values. Featured are statistical calculations and a 64 kwords/channel memory with 256 kwords/channel optional. Options include floppy disk drives. $7,450. Western Graphtec, (800) 854-8385.
Copyright 1998 Nelson Publishing Inc.
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