By Mike Bacidore, Managing Editor
Digital signals and smaller footprints are two of the technological enhancements to signal conditioning that have changed the data landscape over the past decade.
"Digital signal processing (DSP) allows application-specific signal-conditioning modules to be replaced by universal input and output signal conditioning modules that are easily configured for a variety of applications using DIP switches, push buttons or a computer running special software," says George Tsakir, process and fluid power product manager, AutomationDirect (www.automationdirect.com). "Compact module designs, higher accuracy, faster response times and modules that can communicate over a network or the Internet are all additional enhancements made possible by DSP."
Bridging the gap between the signal conditioners manually configured with DIP switches and push buttons and the modules requiring a computer and special software is a new breed of universal signal conditioner configured and calibrated using an LCD display and keypad.
"As technology has advanced along with the diversity of processing applications, the number of dedicated signal conditioners required to accommodate the different inputs and necessary outputs has become cumbersome," explains Jeff Thornton, product manager, Red Lion (www.redlion.net). "Universal signal conditioners—which can accept potentiometer, Ohm, dc current and voltage input, as well as output necessary analog signals—provide a solution to this issue by simplifying conditioning for numerous devices and allowing reduced inventories. Universal signal-conditioner technology combined with custom-calibration capabilities now allow for more than 100 input-to-output configurations."
Processing power available per-channel has risen dramatically over the past decade, explains Ian Lewis, senior vice president, Microstar Laboratories (www.mstarlabs.com). "In many applications, performing noise reduction and other processing on digital data streams, rather than using analog filters or other analog circuits, now makes sense to millions of samples per second even in relatively low-cost systems," he says. "This same development in technology allows data transfer into a normal PC to millions of samples per second, as long as latency isn't an issue in the application."
The enormous reduction in the size of signal conditioners has had a huge impact, says John Lehman, engineering manager, Dataforth (www.dataforth.com). "Given today's widespread use of embedded and portable applications, miniature size was essential," he says. "It is possible to incorporate high-performance, isolated, modular I/O on a per-channel basis for any embedded monitoring or measurement and control system."
Size does matter, agrees Alan Balcombe, global product engineering manager, Weidmuller Application Center (www.weidmuller.com). All types of industrial electronics have shrunk in size over the past decade. "This is particularly true for analog signal conditioners, where the benefits of both module package size reduction, combined with performance and functionality improvements, have come from developments, such as with planar transformers, microcontrollers and surface-mount components," explains Balcombe.
"Taking the familiar Christmas-tree shape, the most space-efficient signal conditioners often accompany pluggable relays for a system approach to signal isolation with a common profile," says Michelle Goeman, product manager—terminal blocks and electronic interface, Wago (www.wago.com). "Compact size also has changed the way jumpering is performed. To retain a common profile and true dimensions, leading signal conditioners utilize push-in jumpers—a flexible comb-style bar. On these designs, every conductor has a corresponding jumper slot."
Derek Sackett, product marketing lead specialist, Interface, Phoenix Contact (www.phoenixcon.com) also cites hard-jumpering of power and common circuits, as well as the use of spring-type connection terminals and quick cabling solutions. "Circuits can be jumpered from underneath the signal conditioner, rather than locked down or in the bus bar," he explains. "In this orientation, the modules are hot-swappable. This quickens troubleshooting and reduces downtime."
Sackett also explains how one potential problem with miniaturization actually can have an upside. When you put electronics into a smaller package, namely the popular 6-mm-wide products, one of the possible issues you face is increased heat buildup, hey says. "If this is done correctly, a benefit of designing the needed electronic circuitry into a smaller housing size is increased power circuitry efficiency," explains Sackett. "This in turn reduces power consumption and heat dissipation, increasing electronic component life and reducing enclosure heat buildup."
Mike Fahrion, director of engineering, B&B Electronics (www.bbelec.com), is seeing a lot of interest and adoption of wireless into I/O systems. "While it may compete with wired solutions, it's often in applications where the cost of wiring would kill the project," he explains. "In some cases, it's enabling engineers to bring previously unreachable inputs into an existing system. The use of wireless doesn't directly impact signal conditioning, but it does mean that the I/O is more likely to be in a remote, exposed location which would create additional demand to embed the signal conditioning within the device itself."
