Look through the collection of pressure sensors that follows, and count the number of devices with advanced technology.
We saw no sensors or transmitters with MEMS technology, for example. Not a single device claims to use IEEE P1451.4 smart sensor technology. Nor did we see any fieldbus-compatible devices.
We saw one device with RS232/IEEE 488, one with a HART interface, and one with an Ethernet connection. Most transmittters are sticking with tried and true sensor interfacing methods, such as 4-20 mA, 0-5 VDC, and so on.
The most advanced devices have built-in microprocessors and software for remote adjustments, remote re-ranging, or temperature compensation.
Today's pressure sensors are smaller and faster than ever before, provide extremely good accuracy and resolution, and perform better than ever. But their manufacturers seem to be resisting the adoption of any other advanced technologies.
It looks like the concept of putting pressure sensors onto the information highway has taken a detour.
In spite of the evidence, market research companies still claim that modern technology is driving the sensor market.
Michael Valenti, principal analyst for Technical Insights, a unit of John Wiley,
We didn't see any wireless sensors, by the way.
"The fastest growth will occur in sensors based on advanced, sophisticated technology especially micro-electromechanical systems (MEMS) and optoelectronics," says a sensors study from The Freedonia Group (www.freedoniagroup.com). "More generally, many types of sensors are incorporating the latest advances in microchip fabrication technology, especially those that are inherently solid-state devices."
It may be that MEMS and microchip fabrication technology are actually being used in some new pressure sensors, but we didn't see it. It could just be that the vendors didn't see fit to include these technologies in their otherwise glowing product descriptions.
Or it could be that market researchers, as is their wont, are taking flights of fancy once again to sell their expensive market studies.
If such products do come to the industrial market, we will be the first to bring them to you. In the meantime, the following pressure sensors represent a cross section of what is actually available today. They may not have MEMS technology or web servers, but the pressure instruments that follow represent some awfully advanced sensor technology.
Type 8311 Pressure Transmitter can switch valves, pumps, and relays on and off. Applications include control of air or fluid pressure in tanks, flow pressure monitoring in water treatment systems, level control in tanks, pressure monitoring in autoclaves, and pump protection systems. It measures line pressures up to 725 psi in fluid temperatures up to 212Â° F. Outputs include 4-20mA, NPN/PNP transistor, and optional 3A/230 VAC or 3A/30 VDC relays.
Lasts a Lifetime
ST2000 Lifetime pressure transmitters have a field MTBF of 470 years and come with a 15-year warranty. Accuracy is 0.0375% and stability is 0.01% per year, both for the life of the transmitter. Rangeability is 400:1 turndown, reducing inventory costs.
Honeywell Process Solutions
The P855 differential pressure transducer has an on-board microprocessor that provides 0.1% FS accuracy. It has an on-board temperature sensor and an error correction system to minimize output errors in extreme environments. It is available in full-scale pressure ranges from 2.5 in./H2O. Standard output signals are Â±5 Vdc, 4-20 mA and Â±10 VDC. RS485 is optional.
Company's 1/32 DIN strain meter/controller measures inputs from load cells, pressure transducers, and any strain gauge sensor. It has built-in 5 or 10-VDC excitation for bridge transducers, supports 4 and 6-wire bridge configurations, and makes ratiometric and non-ratiometric measurements. It connects directly to an Ethernet network and can send and receive data in standard TCP/IP packets.
Pressure-reducing, back-pressure and vaporizing regulators can be used in sample conditioning systems, gas and liquid analysis systems, calibration and carrier gas cylinders and delivery systems, instrument air and specialty gas pressure control. Regulators are available in a variety of piston-type and diaphragm-type designs and all models have a captured inlet gauze-type filter and fine pitch stem threads for better control.
The Series 600 automated pressure calibrator has eight ranges with an accuracy of 0.01% FS of each calibrated range. Suitable for use in calibration labs, it has dual channels, high-speed regulators, and on-board pressure generation. Its color touch screen user interface has multilingual menu capability. Ranges are 5--1500 psia and 10 in./H2O to 1500 psig.
Series 1500 thin-film pressure transducers and transmitters have all-welded construction and choice of integral hermetic connector or molded, integral cable. They have no mechanical fasteners, washers, O-rings, or fluid fills. Full scale ranges are from vacuum to 6,000 psi with accuracies of 0.5%, 0.25%, and 0.1%. Outputs include 0-5 VDC, 0-10 VDC or 4-20 mA.
888/684-0011 http:// www.pcb.com
The Rosemount 3051S meets IEC 61508 and IEC 61511/ANSI ISA 84.00.01 (2004) safety certification requirements, making it a TUViT-certified pressure transmitter for use in a SIL 2 or SIL 3 safety instrumented system. The necessary electronics are simply added to the transmitter either at the time of order, or after purchase in the field as an upgrade. Required proof test intervals can be extended to five years.
Emerson Process Management
The Sitrans P DSIII Series pressure transmitter incorporates software that provides diagnostics and simulation. Diagnostics include high or low limit alarms; peak value registers that store the maximum and minimum values for pressure, sensor temperature and electronics temperature; and two programmable watchdog timers that alert the operator when user-set maintenance and calibration times occur. It also has complete signal simulation, from input through to output.
Siemens Energy & Automation
215/646-7400 x2592 www.sea.siemes.com/ia
Peak Hold Gauge
Falcon Digi Max digital pressure/vacuum gauges automatically capture and display minimum and maximum readings. These battery-powered gauges have an accuracy of 0.25%, 316SS wetted parts with a 1/4 in. NPT connection, and ranges from vacuum to 5,000 psi. Pushbutton zero allows automatic zeroing of the gauge. A NEMA 4X housing is optional.
Absolute Process Instruments
KPSI transducers provide programmable adjustment of the pressure range in the field by up to 10:1, over standard ranges of 0--5 through 0--100 psi. The ability to re-range the unit in the field enables periodic adjustment of zero and span. Thermal compensation provides overall accuracy of 0.25% over the temperature range of -4--140Â° F. The Series is UL/CUL, FM, and CSA approved for installation in hazardous locations. Prices are from $795.
Stainless Steel Transmitters
The Model 831 D 316L stainless steel transmitter provides wet-to-wet differential measurement in ranges from 0 - 6 through 0 - 500 psid. It is suitable for non-vented liquid level tanks, filtration applications, and oil and gas applications where low static pressure is required. The weatherproof transmitter can take a direct spray with forces up to 200 psi without internal leakage, and is compatible with corrosive media.
Industrial pressure transmitters are available in 16 pressure ranges from 14.5 - 8,700 psi with 0-10-VDC or 4-20 mA outputs. The housing is stainless steel and is rated IP67. All transmitters have an M12 electrical connection and a standard G 1/4-threaded fluid connection. A media stop is included with devices rated over 40 bars to contain the process media if the burst pressure is exceeded.
SGT electronic pressure instrument combines the functions of a dual switch, gage and transmitter in a compact, loop-powered device. It has self-diagnostics, on-line testing, password protection, two relays, local indication, a 4-20mA analog output, and is approved for use in Class 1, Div 2 hazardous locations. Instrument is available with absolute pressure ranges from 10--2,000 psia, and from 30 in./Hg vacuum to 2,000 psig.
Sensor Doesn't Drift, Dude
Model 528 strain gauge industrial pressure transducer is resistant to aging, insensitive to thermal transients and pressure cycling, and has less than 0.2% drift per year. It is suitable for industrial and submersible applications such as hydraulic test, bore-hole level, semiconductor processing, and natural gas. All wetted parts are constructed of stainless steel. Transducers are available in ranges from -14.7- 6,000 psi. Compound and absolute ranges are available from 15-300 psi.