Back in April, at the Hanover Fair in Germany, SICK AG and several other manufacturers of sensors and other automation products (including Phoenix Contact, Pepperl + Fuchs, and ifm effector) announced the IO Link working group under the umbrella of PROFIBUS International (PI). Their goal was to develop the specification for a fieldbus-independent communication interface for intelligent sensors and actuators in production automation. Note the emphasis on "intelligent" sensors, that is, those with configuration or diagnostic information to convey: This is what differentiates IO Link from AS-I.
When I visited the company's American headquarters SICK USA in Minneapolis a couple of weeks ago, I learned about its commitment to IO Link-and also its new color vision sensor (CVS) line.
IO Link: The Official Word
IO Link is not a classical bus system, but rather a fieldbus-neutral point-to-point connection for dialog between sensor and controller; the physical coupling of one or more sensors to a fieldbus takes place with the help of an IO Link connection module. IO Link has been designed as an open interface and can be integrated into all current automation communication systems with no effect on speed.
According to PI, IO Link will let you take advantage of automation solutions with system-wide, open communication to the individual sensor/actuator. You can dynamically change device parameters through the PLC, access diagnostic information down to the sensor/actuator level, and easily exchange devices during operation. In particular, you can execute a "teach-in" with IO Link for easy and precise sensor settings.
The first IO Link sensors will reportedly be available this fall, and SICK expects three industries to recognize its benefits first: pharmaceutical, packaging, and handling/warehousing.
"IO Link will have positive effects on the design and control technology of machines and plants in future," says SICK in its news release. "Largely passive function elements will become active participants in dialogue with the control level and, in addition to switching signals, will autonomously report errors and supply state information. IO Link is thus the sensor communication of the future." SICK adds that IO Link provides increased plant availability and the possibility of validating entire machines.
What The Bloggers Say
The PTO PROFIblog's entry on IO Link, "IO-Link, HART for discrete?" says, "similar to HART, you can use an IO-Link device in a standard system and a non-IO-Link device in an IO-Link system. In either case, you don't get the advantage of access to the configuration and diagnostic information over the wire."
The IEB blog states, "sensor users simply want something to update traditionally-cabled systems with the more-intelligent devices that have appeared recently with greater sensing ability (e.g. optos with 16 bit outputs) plus more parameterisation capability and diagnostics. A bus-based solution needs a culture change, may be more expensive and may even be less powerful!"
How It'll Happen
SICK is implementing a new ASIC across product lines for photoelectric switches and, in particular, proximity switches to upgrade the switching output of a sensor to a communication interface for a reasonable cost.
The First True OCR Sensor
SICK recently launched a new line of color vision sensors (CVS) that provides cost-effective alternatives for applications that would otherwise require expensive vision systems. It includes four sensors, CVS1 Easy, CVS2, CVS3, and CVS4. The latter is what SICK calls the "first true optical character recognition (OCR) sensor," a claim that translates to suitability for date and lot code inspection. It can count characters, reads up to 60 characters on six lines, and automatically updates itself for expected date code changes with an onboard real-time clock. The CVS4 is well suited for applications in the food and beverage market where expanding FDA regulations call for better traceability on products.