A recent market study by Venture Development Corp. reveals the North American market for linear displacement sensors including encoders, linear variable differential transformers (LVDTs), laser systems, magnetostrictive, potentiometers, capacitive, inductive and ultrasonic products totaled $339 million in 2006. VDC says the largest market for LVDTs is for military/aerospace applications. These devices do well in harsh environments; they have only one moving part and little friction between the moving ferromagnetic core and the cylinder in which it moves.
LVDTs are used in automation machinery, civil/structural engineering, power generation, manufacturing, metal stamping/forming, OEM, pulp and paper, industrial valves, R&D and test and automotive.
National Instruments says be mindful that LVDTs might operate at excitation amplitudes and frequencies other than those listed by the manufacturer. Also, stay within the recommended travel specification of your LVDT, and beware of excitation-signal cross-talk between channels.
A tutorial from Macro Sensors lists several other reasons why you should consider LVDTs. They include infinite resolution, over-travel damage-resistance, single-axis sensitivity, separable coil and core, null-point repeatability, fast dynamic response and absolute output.
These sensors find extensive use with pneumatic and hydraulic cylinders and are particularly useful for long strokes. Growth of these sensors is expected to be at an above-average rate over the next five years, with the highest growth-rate expectations for use in metalworking, assembly/robotics equipment and valve applications.
The highest growth rates in the VDC study are for laser systems at 10% and capacitive linear displacement sensors at 8%. The markets for both are small, but each is expected to grow since users are seeking higher accuracies, which these provide. This is particularly the case in the semiconductor and electronics industries, where more precise measurement capabilities enable shrinking the size of electronics.
Tru-Vue photoelectric background-suppression sensors have a 50-mm sensing range and deliver target detection regardless of target color and reflectivity, with detection unaffected by shiny background objects, and eliminate the expense and installation of reflectors or through-beam alignment. They have a 4-in-1 output that automatically detects the connected load and sinks or sources.
Pepperl+Fuchs
330/486-0001
BIM-UNT universal magnetic-field sensor detects the position of a piston on standard pneumatic cylinders via magnetoresistive, board-level technology and has a sensing face in the front of the sensor to help detect short-stroke cylinders. The sensor comes with a quick mount tab that helps seat the sensor in the cylinders groove
Turck
800/544-7769
E3X-DAC white LED fiberoptic sensor detects true colors in marks and workpieces independent of light intensity and sensing distance variations. The 10-mm-wide amplifier unit processes color detection through an RGB light-receiving element. One-touch teaching simplifies setup for high-speed packaging and sorting, and electronics packaging including small parts and fine wires.
Omron Electronics
866/88-omron
SA1-RTD surface-mount temperature sensor mounts on flat or curved surfaces and provides Class A accuracy. Based on a 2x2x0.8-mm thin-film platinum RTD and supplied in PFA-insulated 3 or 4-wire configurations in 1, or 3 m lengths or custom lengths with self-adhesive backing or permanent mounting, the RTDs can be used for monitoring motor and transformer core heat and test insulation capabilities.
Omega Engineering
203/359-1660
ACT current transducers, in split and fixed-core models, have jumper-selectable current inputs and 4-20 mA or 0-10 Vdc outputs. Split-core models make using portable data loggers easier, and simple connection enables power consumption or other motor status display. For safety and to eliminate voltage drop, the output is magnetically isolated. The devices are UL, cUL and CE approved.
AutomationDirect
770/889-2858
S51 18-mm sensors in through-beam, retro-reflective, polarized retro-reflective and diffuse modes have a flat, cylindrical housing that offers mounting choices using traditional 18-mm locking nuts or by direct-mounting with two-through holes. The mounting-hole configuration makes it possible to replace many non-threaded sensors. S51 sensors have a sensitivity adjustment and a variety of output configurations.
IDEC
800/262-4332
GT all-in-one integrated contact sensor for height and thickness measurements requires no external PLC or external data processing. Designed for automatic in-line measurement, the IP67-rated GT has a linear ball-bearing spindle tip that pneumatically extends and retracts for each measurement cycle. The ball-bearing tip eliminates wear and abrasion damage from contact with high-speed moving target surfaces.
Keyence Corp. of America
888/539-3623
MagRes compact, self-contained, absolute multi-turn encoders high-density housing has two M12 input and output plugs for integration into Profibus-DP systems where space is tight. It has 13-bit resolution in single-turn models and 16-bit in multi-turn versions. It measures 58-mm diameter and 42-mm deep.
Baumer Electric
800/937-9336
Vibration switch is a low-cost, self-contained monitoring system for rotating or reciprocating equipment, providing alarm or shutdown if excessive vibration levels are reached. All sensing and electronic components are included in the standalone switch with an alarm LED. It has an integral relay to provide failsafe operation with both normally open and normally closed contacts.
Hardy Instruments
800/821-5831
Temposonics R-series EtherCat sensor overcomes bandwidth and node limitations found in commercial networks. Its available with one to five position magnets and can be customized to document position, velocity and acceleration, as well as custom smart functionality.
MTS Systems Corp.
919/677-0100
FX-100 Series fiberoptic sensor is 9-mm wide with integrated mounting holes. It has a dual digital display for simple setup and automatic pushbutton teaching and external input capabilities. It has threshold tracking, timers, LED attenuation and interference prevention.
Panasonic Electric Works Corp. of America
908/464-3550
PSen non-contact, magnetic safety switches have a 12-mm diameter and measure switching distances of 8 or 15 mm. An additional signal contact is available to display the status of the safety switch via a connected PLC. Approved to Category 4 of EN 954-1, PL e of ISO 13849-1 and SIL 2 of EN IEC 62061, the switches are suitable where it is difficult to align machine gates precisely or with high levels of vibration.
Pilz Automation Safety
734/354-0272
Osiprox inductive cylindrical sensors were developed for extreme temperatures, humidity, and equipment washdowns using chemical agents. With IP67, IP68, and IP69 ratings, these sensors, cables, casing and front face are built with FDA-approved materials.
Schneider Electric Sensor Competency Center
800/435-2121
S300 safety laser scanner for applications where the hazardous area is less than 2 m. It has low power consumption for oncoming fork detection on AGVs or safeguarding workers in the path of manned forklifts and transfer cars. It has a 270° scanning angle.
Sick
952/941-9287
LazerSafe LZS-003-HS safeguarding system developed for hydraulic press brakes makes complex bends with a minimum of settings while maintaining press speeds. Two flat bands of 40-mm-wide laser light continuously monitor the zone below the punch. It can detect obstructions to 4 mm, while remaining tolerant to inherent vibration.
Honeywell Wintriss Controls
800/586-8324
MT miniature photoelectric sensors for industrial machine applications are available in polarized-reflective, diffuse-reflective, and through-beam modes. Each sensor measures 12x33 mm, has sensitivity adjustment, a yellow LED for output indication, a green LED for stability indication and an M8 4-pole connector.
ASI
877/650-5160
Series 9000 photoelectric sensors use ASIC technology for added functionality. 42GSP-9000 has a teach function that eliminates manual adjustment of sensitivity. 42GLP contains a manual adjustment potentiometer to adjust sensor sensitivity.
Rockwell Automation
414/382-2000
World-Beam QS18LD laser diffuse and QS18LLP laser retroreflective sensors use visible Class 1 lasers and tightly collimated sensing beams. They also have extended sensing ranges. QS18LD senses targets 300 mm away, while QS18LLP delivers retroreflective sensing up to 10 m.
Banner Engineering
888/373-6767
AST4100 OEM pressure sensor has 0.875-in. diameter and stainless steel construction of the header and housing makes it suited for corrosive environments with pressure ranges 0-25 to 0-10,000 psi. Units are available in compound ranges, as well as in bar and Kg/cm2 outputs. Outputs include 10 mV/ V, 0.5-4.5 V ratiometric, 1-5 V, 1-6 V, 0.25-5 V or 4-20 mA.
American Sensor Technologies
973/398-9900
Model 9360 non-contacting rotary, dual-output Hall effect sensor has 360° rotation and is suited for high-vibration environments. Electrical angle is 0-359.9°. Operating temperature is -4085 ºC. Accuracy is +/-0.6% FS. The sensor is ISO9001 and TSI6949 certified.
Duncan Electronics
949/341-9500
AS5305 magnetic linear motion encoder IC is designed for linear motion and off-axis rotational measurement in industrial drives, x-y stages or electronic motors. A system-on-a-chip, combining Hall elements and a signal processor has incremental measurement with a resolution to 14 μm per position step.
Austriamicrosystems
+43(0)3136 500 5856
RS 1500-120 fractional-turn, contactless rotary position sensors measure angular displacement of quarter-turn ball and butterfly valves, air flow dampers and diverter gates used in packaging machines. Available with a 24 Vdc input and 0-10 Vdc output, or a two-wire, 4-20 mA loop-powered transmitter I/O.
Macro Sensors
856/662-8000
Line of RTD sensors can be configured with options including element type, lead-wire configuration, termination style, sheath materials, lengths and diameters, process connection heads, transmitters, thermowells, spring loading, flanges and surface mount packages. Operating range is -200650 °C. The linear change in resistance per degree change in temperature allows for less complex instrumentation and requires no cold junction compensation.
Watlow
314/878-4600
Model HSE-1 evaluator monitors and logs key parameters of resistive and hybrid-capacitive humidity sensors via a USB port. Its screen displays relative humidity, dry-bulb and dew-point temperature readings. Users can display and log selectable functions of 12 different sensors. The evaluator has a display resolution of a few tenths to 2% over the selected sensors full operating range and works with Windows 2000/XP/Vista.
Ohmic Instruments
410/820-5111
DigiPyro PYD 1988 and 1978 digital photoelectric infrared sensors for industrial motion-sensing applications have window-detection sizes of 4.60x3.4 mm2 and 3x4 mm2, dual-element design, standard three-pin TO-5 metal housing, 15-bit output direct link, and infrared window transmission. They have low EMI sensitivity and are RoHS-compliant.
PerkinElmer Optoelectronics
877/pki-nyse
IP68-rated Gemco 953S VMax linear displacement transducer provides continuous position feedback and has up to 1 µm resolution and stable position feedback for cable runs 1,200 ft from the host controller. 953A (analog), 953D (digital) and 953S (SSI) LDTs have active measuring range to 300 in., and power supply voltages ranging 730 Vdc. Analog output units offer programmable zero and span, and all units offer visual and output signal diagnostic feedback.
Ametek Automation & Process Technologies
800/635-0289
Model 7290D variable capacitance accelerometer has onboard, microprocessor-based temperature compensation for high thermal stability for measurement of relatively low-level acceleration that requires measurement of whole body motion immediately after the accelerometer is subjected to a shock motion and the presence of severe vibration inputs. Gas damping and internal over-range stops enable its anisotropically etched, silicon sensing element to withstand high shock and acceleration loads.
Endevco
949/295-5515
