SICK is expanding its family of capacitive sensors with further sensor variants. The CM 30 is now available in a 2-wire design for an operating voltage of 250V ac.
Another device, the CM 18 PTFE, is specially designed for regulating the filling levels of acids, alkalis or solvents, as well as checking presence in areas with aggressive steams and vapours.
High immunity to electromagnetic interference, increased switching distances of up to 25mm, and designs with options for flush or non-flush installation, are the highlights of capacitive sensors from SICK.
Three different sensor designs are available: the CM 18 in a round M18 housing, the CM 30 in a round M30 housing, and the plastic CQ 35 in a 35mm square design.
The ranges of the sensors are, with non-flush installation, 3-12mm for the CM 18 and 4-25mm for the CM 30 and CQ 35. Response sensitivity can be adjusted steplessly via a potentiometer.
All devices offer an enclosure rating of IP67 and are available with M12 plugs or a 2m connection cable. UL and CSA approvals have also been obtained.
A particular highlight of the capacitive sensors from SICK is their high electromagnetic compatibility (EMC). This reliably prevents spurious switching resulting from, for example, electrostatically charged granulate in bulk material silos, mobile telephones, and radio devices, or interfering surge voltages caused by magnetic valves, contactors or frequency converters.
Capacitive sensors are mainly used in applications for which optoelectronic sensors are unsuitable as a result of, say, a high potential for contamination or a lack of "eye contact" with the target material.
These include regulating filling heights in silos of animal feed, grain or plastics; checking presence on timber processing machines; use in irrigation systems; detecting pallets in conveyor systems; as well as detecting position and checking the filling heights of bottles in filling plants.
By using the material PTFE (polytetrafluorethylene) for the housing, and M18 threaded connections, the CM 18 PTFE can be used for regulating the filling levels of aggressive media, e.g. hydrochloric acid, sulphuric acid, phosphoric acid, a variety of alkalis, and numerous solvents.
The same applies for object detection in areas in which these materials can be present as gases, steams or vapours.
At the same time it is also suitable for use wherever plants require frequent cleaning with chemicals or at high temperatures.