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Sensing edge Technologies explained
Safety contact strips are known by a wide variety of names: closing edge safety device, safety edge protection, safety strip, contact strip, optical safety strip, optical sensing edge, safety edge, anti-crushing safety device, shearing point security, rubber switch, rubber profile. All these terms stand for the same product and have the same purpose.
Sensing edges are tactile safety devices. They stop dangerous movements following unwanted touch or contact and can react quickly even at sensitive contact points. This way you can protect your business from person damage to persons and / or secure your machines.
Even if the choice of optical sensing edges and profiles is diverse, three building elements coincide: the C-rail, (usually) an aluminium profile, the rubber profile, and the sensors for the optical sensing edge, as well as the end caps for the electrical safety edge.
Before you finalise your order check for the required technology and correct measurements.
Which type of safety edge to you need?
For the information of the type of safety edge (technology) you require for your door, a quick look at the wiring diagram of your machine or door control unit can help. The entry resistive safety edge terminating resistor 8k2 Ohm refers to an electrical safety edge the term Fraba-OSE or the indication of the need for an optical safety device in general denotes that an optical safety edge is needed.
Should your machine or door control unit only accept potential-free switching signals as a sensor input, we recommend you use a safety edge combined with a monitoring unit.
Technology 1: Optical Sensing Edge
The Optical Sensing Edges (OSE) from the FRABA VITECTOR company are based on the principle of optical safety strips. These types of safety edges are particularly found in industrial doors. Here, the risk areas are equipped with a hollow rubber profile as closing edge protection. In the round hollow chamber of the rubber profile, a round pair of opto-sensors is also installed, which generates an infrared beam from the photo eye in the hollow chamber. If the contact safety strip is touched by a person or an object, the shape of the sensing edge is deformed, the beam emitted by the photo eye is broken and the dangerous movement stops. The height of the run-on chamber should be set in such a way that the dangerous movement stops while the obstacles are still in the flexible area of the “crumple zone”.
Appropriate Measurements, the C-rail
Please ensure you have the correct measurements when you order the rubber profile for the optical sensing edge. The C-rail may already be built into the door or the machine or may have been ordered from our shop and retrofitted. To ensure that the C-profile and rubber profile fit together properly, measure the C-profile on your door carefully before placing your order.
Electrical Connection
The colour of the sensor’s housing reveals the manufacturer of your safety device. The electrical connection of the different manufacturers is, however, usually similar and corresponds to the following diagram: The three connection leads of the OSE-sensors will be connected according to the operating instructions. The individual wires have the following colours corresponding to their functions:
- Brown = supply voltage (+)
- White = supply voltage (-)
- Green= Safety signal, which will be monitored by the monitoring unit
The Advantages of Optical Sensing Edges
he optical sensing edges will secure the closing edge both of industrial doors as well as the machinery that these sensors are often installed on. The opto-electric technology offers several advantages:
- A torn rubber profile does not mean loss of function as the light beam continues to work uninterrupted. This guarantees high availability of the system. The machine or the door will only stop working when the chamber becomes very dirty.
- The safety contact strips can be assembled and modified on site without glue or other installation aids. A properly mounted sensing edge has an IP67 protection rating and is therefore also suitable for use in demanding environmental conditions.
- The "FRABA OSE" interface is already built into many common control units. Accordingly, the safety contact edges can be connected without additional monitoring devices.
- The optical sensing edges offer a higher safety level up to performance level PL e /category 4 according to EN ISO 13849-1 and are therefore also suitable for demanding applications.
The safety edges can also be ordered ready-made or the rubber profiles can be shortened by hand.
Our top sellers: Optical safety edges
Best Seller
FRABA VITECTOR OSE-S 6501 Optical Edge Sensors Transmitter Tx 6,5m/Receiver Rx 0,5m PVC-Cable
€53.00*
plus VAT
in stock
Best Seller
Technology 2: Electrical Safety Edges
This safety edge provides a pressure-sensitive sensor which functions as a closing edge safety device. Two areas for the safety edge which require EPDM profiles consist of a material mixture that conducts electricity. These two areas are connected by a corresponding end cap with built-in resistor. When the switching surfaces come into contact, e.g. by hitting an obstacle, an electrical contact with a low contact resistance of <500 Ohm is created. Accordingly, when the safety edge is not actuated, one measures a contact resistance of approx. 8k2 Ohm. When actuated, this resistance drops to a value <500 Ohm. This change in contact resistance is monitored either by the machine control or by using an ELMON evaluation unit. An actuation of the safety edge is reliably detected, and the dangerous movement is stopped.
Often, machines or sliding doors are equipped with more than one safety edge per direction of movement. SENTIR Safety Edges are particularly suitable in this case. A safety edge can also be assembled as a continuous edge. In this case, the end resistor is removed and instead both ends of the safety edge are manufactured with a connection cable. These edges can be connected in series and only the last edge is equipped with an 8k2 end resistor. In this way, all series-connected safety edges are monitored as one sensor element and there is no need for expensive evaluation devices or controls for each individual safety edge.
C-rail and appropriate measurements
Make sure you have the exact measurements when you buy the rubber profile. The C-rail might already be installed or may have been retrofitted. To ensure that the C-profile and rubber profile fit together properly, please measure the existing C-rail carefully before ordering so that you order the correct safety edge for your door
The advantages of electrical safety edges
One of the biggest advantages electrical safety edges have over optical safety edges is that it’s possible to customise it to fit into special designs like corner applications. Electrical safety edges also excel because they offer series circuits which are useful in applications that require one evaluation channel to monitor several safety edges such as in sliding doors and other applications with multiple shearing points. Because electrical safety edges behave like passive systems, their power consumption is amongst the lowest in safety edges, they are therefore optimally suited for use in radio control systems.
Properties:
- Many different configurations with optimum profile height available for every application
- Fast, sensitive switching mechanisms
- Profile with two chambers, with integrated and protected switching chamber
- Extensive modification possibilities
- Various sizes available in stock
- Numerous standard designs of the mounting foot
- Series circuit possible for several safety edges
Our top sellers: 8k2-Sensing Edges
Best Seller
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