C23 photoelectric sensors keep high-volume food packaging operations under control


Versatile C23 photoelectric sensors from Swiss manufacturer Contrinex play a vital role in managing high-volume, automated food-packaging operations. Manufacturers rely on these high performance devices to maintain an appropriate degree of control across multiple discrete process stages, ensuring maximum uptime. The C23 Series is available with IO-Link, a standardized point-to-point serial connection protocol, at no additional cost, offering the advantages of digital communication without the need for special cabling.

Customer Values

  • Outstanding process monitoring and control capabilities
  • Fast, easy set-up and reconfiguration
  • Reduced handling and visual inspection costs
  • Less downtime

Specific Product Advantages

  • Best-in-class sensing ranges
  • Special optics for excellent background suppression
  • Precise detection of small, fast moving objects
  • IO-Link on all PNP sensors.

Customer Application

Today’s process plants are highly automated and utilize multiple sensors to maintain an appropriate degree of control. Food-packaging operations are typical, with multiple discrete process stages, each with a different problem to solve. Factory management expects near 100-percent uptime, and invests in pre-handling common problems that would otherwise cause line stoppages or allow faulty product to reach the customer.The process itself hasn’t changed much over the years: products are transported by conveyor and presented for sealing or wrapping, secondary packaging and labeling before passing to the dispatch area. At each stage, in-line checks ensure that the item is present, that it is oriented correctly and that the packaging and label are applied correctly and securely. Additionally, where multiple conveyors feed a single operation, the control system may adjust individual conveyor speeds to maintain a constant downstream flow.

Customer Solution

The Contrinex C23 Series of miniature cubic photoelectric sensors addresses these needs perfectly. Developed to satisfy the demands of a broad spectrum of industries and applications, these top-of-the-range sensors are available in diffuse, background suppression, retro-reflex and through-beam sensor types with adjustable ranges. C23 background-suppression sensors also feature pinpoint LEDs that allow precise detection of small objects without the need for laser technology.Plant-wide communication is another mandatory requirement for manufacturers, and the C23 Series doesn’t disappoint. The entire range is available with industry-standard PNP or NPN 3-wire or 4-wire output. IO-Link, a standardized point-to-point serial connection protocol for sensors and actuators, is enabled on all PNP devices at no additional cost, offering the advantages of digital communication without the need for special cabling.Presence sensing and product-orientation checking on fast-moving conveyors are routine tasks for the C23 diffuse and background-suppression sensors, depending on the material and color of the items to be detected. At each detection point, a single photoelectric device either detects the presence or confirms the correct orientation of an item as it passes, and may optionally be used as a counter to calculate throughput rates in excess of 1,000 items per minute.In common with the entire C23 Series, these sensors feature industry-standard 20mm x 30mm x 10mm ABS housings with the option of an integral M8 connector or a hermetically sealed 2-meter PVC-sheathed cable. Special, purpose-designed optics give excellent black-white background-shift characteristics for sensing gray or black targets against light-colored or reflective backgrounds. Customers enjoy best-in-class sensing distances up to 1500mm (diffuse) and 300mm (background suppression), respectively.After sealing or wrapping, products may require secondary packaging for additional protection, aggregation or retail display. Typically, C23 retro-reflex sensors monitor the flow of wrapped items into the consolidation area, confirming that each is presented correctly and diverting any non-conforming products off line. For smaller items, monitoring from above with a single diffuse sensor is a suitable alternative. In each case, the “Normal” switching frequency of 1.5 kHz is adjustable via IO-Link to 500 Hz (“Fine” mode) or 5 kHz (“Fast” mode), depending on the requirements of the individual application.Checking that packed items conform dimensionally is another task for C23 retro-reflex or diffuse sensors. Mounted either to one side or above the packaging line, and with optics set to a pre-determined target distance, these highly reliable devices make light work of identifying any damaged or malformed packs and initiating a rejection sequence. Throughput rates of hundreds of packs per minute are common in busy process plants.Once packaged, products are labeled. Here, the Contrinex KTS-4155 contrast sensor checks label alignment and detects the presence of specified label markings. Thanks to a small and extremely narrow 1.5mm x 3.5mm light spot, detection of very small print marks is possible. Simultaneously, automatic selection of emitter diodes in three different colors ensures reliable detection of even small differences in contrast on printed surfaces.Now ready for the retailer, items proceed to the final packing area. Preferred packaging materials include shrink-wrapped trays or cartons, each containing multiple packs, ready for consignment into the distribution network. One final task for the C23 Series is detecting and counting the finished packages as they proceed to the dispatch area. Here, the C23 through-beam sensor is the perfect choice, with sensing distances up to 30m and integral alignment aid to simplify set-up.The Contrinex C23 Series of photoelectric sensors has the capability to communicate remotely with a plant-wide control system, thanks to its implementation of the IO-Link protocol on all PNP devices. In a typical flexible process plant, each packaging line runs multiple product variants during the course of a day. Designed to simplify integration, IO-Link sensors are compatible with all IO-Link master versions, allowing set-up and diagnostics to be conducted centrally.The C23 Series allows remote adjustment of the sensor mode. There is little that cannot be done conveniently and centrally as the demands of the production schedule dictate. During a changeover – for example, from light-colored items to those with darker packaging – the amount of manual intervention required is minimal. Sensor parameters can be reset via IO-Link using predetermined values, and downtime is kept to an absolute minimum.Remote sensitivity adjustment and output reconfiguration are standard features of the IO-Link protocol, as is the capability to download new parametric values to any number of sensors across the system. Where multiple through-beam sensors operate in close proximity – as may be the case with sequential detection points – the LED emitting sequence can be set via IO-Link to one of several pre-determined patterns of light pulses, preventing cross-talk and unwanted interactions.Various event flags are triggered according to the system configuration. These include detection state and stability alarms, LED regulation limit notification, under-voltage, excess temperature and short-circuit detection. Sensors additionally transmit actual and maximum temperature data in real time.The Contrinex C23 Series is a versatile, cost-effective and highly reliable solution for manufacturers across the food and beverage sector. Contrinex provides technical and commercial support via an extensive international network, ensuring that every customer has access to expert product knowledge and directly relevant applications experience. The no-cost option of the industry-standard IO-Link protocol ensures that best-in-class performance is coupled with ultimate ease of use in even the most demanding circumstances.