Sometimes well-known technologies like presence sensors don't change and gain new innovations as much as the world changes around them, wakes up to capabilities they already have and drags them into new applications.
"With so much economic globalization and new markets emerging, there's increasing demand for automation," says Kristen Chenowski, sensors and industrial products marketing manager at Omron Automation and Safety. "This means more need for worldwide safety standards and certifications, such as UL, CSA and CE, which means more presence sensors in mats, light curtains and other devices to protect people."
Just under a year ago, Chenowski adds, Omron released a series of fiber-optic presence sensors that have a maximum through-beam range of 6 meters, which is a big gain over the previous 4-meter maximum.
"An improved microprocessor, better fiber-optic connections to its amplifier and greater percentage of emitter light returned to the amplifier give it more stable internal detection, which allows it to help with more challenging targets," adds Chenowski. "Also, for food and beverage applications, we just released a photoelectric sensor family in June and our stainless-steel sensor, which is epoxy-sealed, washdown-rated and tested for EcoLab/Diversey chemicals and cleaning agents."
Tony Udelhoven, sensor division director at Turck Inc., reports that the overall microprocessor revolution during the past 10 years is also enhancing many sensor designs and capabilities, such as Turck's Q-Track line, and giving users more control over their sensors' measurement spans and other parameters. Q-Track also added the IO-Link protocol in 2011.
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"Previously, a user might buy a sensor for an encoder with 1,024 pulses per revolution, but if they later needed 584 or 3,400 pulses, then they had to buy another encoder," Udelhoven explains. Now users can adjust pulse counts in the sensor. Linear distance transducers produce analog values over their sensing ranges, such as 0 to 10 V over 200 mm, but some users might want to adjust the span by starting at 110 mm and going to 190 mm, and now they can do it. They also can change outputs from 0 to 10 V to 4-20 mA, and even adjust the slope of their sensors. It's all done in the software."
Over the five years since they were introduced, Turck's inductive linear and rotary sensors have progressed from linear distance transducers to 12-bit rotary transducers to 16-bit, internal-resolution sensors with a wide variety output configurations, explains Udelhoven.
To help presence sensors communicate with their new applications and users, Kevin Zomchek, presence sensing marketing manager at Rockwell Automation, agrees the biggest enabler is IO-Link, which is standardized, point-to-point and complies with the IEC 61131-9 standard.
"IO-Link eases commissioning, allows better troubleshooting and is more flexible," Zomchek says. "So instead of just getting simple, discrete on/off inputs from sensors, we can use IO-Link to communicate with sensors, see their operating margins and check more condition-based information, such as whether a lens might be dirty. We can even use IO-Link to change sensors' setups on the fly by accessing their profiles and parameters through the HMI, and use IO-Link's automatic device configuration (ADC) function to download new parameters."