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| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | CONTRIhEX) | | | | | | | | | | are very good. A non-flush mounted, installable M30 device is recommended here. Often the fine adjustment of the switches cannot be accomplished statically (for example with a moving object) and must be achieved while the machine is at operating speed. A small error from the personnel installing the device for the first time can lead to damage to the equipment and in addition can also lead to accidents to personnel. Here, the installation of devices with a large switching distance is an obvious advantage - and the risks of a collision with a moving objects are minimized. Case 5: Field maintenance While it is good practice to use trained industrial production personnel for the installation and adjustment of switches, maintenance at the user' facility should not require such high standards. Defective standard proximity switches can be replaced using unskilled personnel since the need for high precision installation is not now so important. Case 6: Replacement of original proximity switches During the initial setting up of an installation, the proximity switches chosen often only just fulfill the requirements of the situation - usually due to cost considerations - which can increase the risk of mechanical damage to the equipment. However, replacement of initially installed switches by switches with a large switching distance, in particular in well-known trouble areas, can improve this situation and reduce costly machine downtime. Case 7: Detection of thin wires The use of inductive proximity switches for the detection of thin wires is in general difficult due to the small effective surface, and is in reality often impossible. Here, photoelectric devices are much better (laser photoelectric barrier devices or solu | | | | | | the size M18 is sn = 12 mm. The requirement is therefore, easily fulfilled. Case 2: Dependence of switching distances on gearwheel teeth size The effective working surface, B (see fig. 4) is much smaller than that of a standard measuring plate, A (as specified in any catalogue). However, with a much less effective measuring surface, the switching | | | | | | | | | | B | | | | | | | | | | Fig. 4 distance becomes very much reduced. For example in fig. 4, a distance of 2 mm (catalogue value) might be reduced to, say, 0.5 mm (dependent on the cross-sectional size of the gearwheel teeth). The resulting switching distance in these cases is often too small and in the practical installation there is always the danger of mechanical damage to the switching device due to contact with the gearwheel teeth - especially where a lot of adjustment work is required. The installation of a device with a large switching distance gives, in this example, a switching distance of 1.5 mm, which solves the problem. The detection of cables with standard inductive devices is, as a rule, not possible. Firstly, the cable isolation prevents the | | | | | | | | | | tions with optical fibers). This solution does
| | wire | | | | | | | | | | involve increased costs, and moreover, installation in polluted environments requires special precautions and skill. In many cases proximity switches with a large switching distance offer an interesting alternative. Non-flush, M30 sized devices are the best suited. Copper wires of diameter 0.5 mm can be, for example, recognized at a distance of 6 mm, whereas with standard devices this recognition is impossible Case 8: Application of protection covers | | | | | | | | | | Condist®-Device «KB | | | | | | Additional protection for these devices, such as covers and top caps, is possible for use in hostile environments or as protection against mechanical damage. However, an undesirable reduction in the | | | | | | | | | | | | | | | | | | useable switching distance will be incurred by using this protection. Devices with a | | | | | | | | | | | | Protection cover | | | | | | | | | | | | | | | | maintain an acceptable result. | | Fig. 7 | | | | | | | | | | | | | | Case 9: Sheet metal processing Processed and unprocessed sheet metals require larger mechanical tolerances than other metal parts. This leads to, for example, the problem of presence detection. If the switch is installed near to the moving part of sheet metal for reliable switching, the danger always exists of mechanical damage to the switch. If it is installed at a industrial safe distance, the recognition is unreliable which impedes the production run or procedure. Inductive devices with large switching distances by their very nature provide a great advantage. | | | | | | Fig. 5 | | | | | | | | | | | | | | 2 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
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