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light position switch Belt alignment switchGear-switches

For process automation in both industrial plants and mobile machinery, the Schmersal Group has a full spectrum of position and limit switches ranging in size from big to small. The product range starts with micro switches for mechanical engineering projects. Long-life standard switches are universally deployed in a wide variety of machines. Application areas for gear switches are as diverse as stage engineering and lifting equipment. The product portfolio also covers robust switchgear for operation in the rough ambient conditions typical of heavy engineering industries such as the materials handling, mining and steel industries.


In the 70s, Schmersal had begun work on a range of non-contact switchgear, and was soon a pioneer in the development and manufacture of inductive proximity switches. Today’s products for the automation industry include, among others, magnetic reed switches for the materials handling and lift switchgear industries. Robotics and automated production lines are just two areas where the IFL range of inductive proximity switches are deployed. Besides the standard versions, customised variants compliant with special requirements such as high operating temperatures or sector-specific approvals (e.g. Germanischer Lloyd) are also available. A variety of sensors for safety-relevant applications are also available.


Automation Technology

Inductive Proximity Switch
Application, design and mode of operation:
A proximity switch is a device which causes a switching action without physical contact. SCHMERSAL proximity switches respond to targets that come within the active range of their generated sensing fields. These units are completely self-contained, and house a field generator, amplifier, and other necessary circuitry to accomplish electronic switching.

The units are all solid state and have no moving parts that can wear out. The electronic switches are not susceptible to contact contamination, contact erosion, or material transfer as are mechanical switches.

Their service life, within their specified ratings, is virtually unlimited. The switching is insensitive to vibration, and is positive (full step function) without chatter, regardless of how slowly the target approaches or recedes from the sensor.

The oscillator resonant circuit, located in the proximity switch, uses an open core coil to help produce a concentrated high frequency electro-magnetic (RF) field, which emerges from the active surface of the sensor. If a metal target (e.g. metal) enters this field, eddy currents are induced. The floating induced eddy current draws energy from the LC circuit (L: coil, C: capacitor). The load on the oscillator circuit evokes a decrease in the oscillating amplitude. The oscillator is attenuated.

The decrease of the oscillating amplitude is converted into an electrical signal by the electronic circuit, which leads to a change of switching state of the proximity switch.

When the electric conductive material is removed from the inductive field, the pulse amplitude increases and via the electronic circuit the original switching position is recreated. The oscillator is attenuated.

Photo-electric Proximity Switches

Position Switch

Position switches with safety function are suitable for sliding and hinged safety guards which need to be closed to ensure the necessary operational security.

In combination with safety monitoring modules all position switches class 1 shown in this chapter achieve Control Category 3 or 4 to EN ISO 13849-1.

Further applications for positions switches class 1 are most varied positioning duties. The variety of requirements to be found in practice can be met in detail by means of a wide range of actuating elements.

Design and mode of operation:

On the position switches class 1 the guarding device and the positive break NC contact are positively linked.

Enclosure rating of all the safety switches is IP 67. The safety switches can be fitted in any desired mounting position.

Magnetic Reed Switch

Along with the mechanically operated limit switches, magnetic reed switches (magnetically operated) have been constantly gaining increased importance. They can be regarded as a complement to the plunger, roller and turret head operated limit switches and as an important addition to electronic proximity switches.

Rotating Spindle Limit Switch

This rotating spindle limit switch with snap-action insert is only fit for use in normal to average operating conditions, e.g. for machine tools, cranes and conveyors. Protection class IP 65 to IEC/EN 60529.

Pull-wire Switches

The pull-wire switches are used to give signals to start machines and to open or close electrically driven doors, gates and barriers.

The pull-wire switches are manually operated by pulling.

Slack-wire Switch

The belt alignment and slack-wire switches are suitable for use on material handling equipment.

The slack-wire switches monitor the wire rope tension. With correct tension present, the switch is actuated.

Belt Alignment Switch

The belt alignment and slack-wire switches are suitable for use on material handling equipment.

The belt alignment switches are actuated, when the conveyor belt becomes misaligned. Depending on the plant arrangements, this signal can be used to switch the equipment off or to provide automatic correction of the belt alignment.


The gear-switches are suitable for use in the most varied application. In studios and on stages, applications include the control and positioning of carriages, portals and bridges. An important field of application is for the monitoring and control of outriggers, trolleys and lifting movements for cranes. On industrial ovens, gear-switches are used on door and gate control systems. Further applications are to be found on waterways (control of weirs and locks), in environmental protection (sewage plants, flue gas treatment plants), greenhouses and sport stadiums (roof controls).

Micro Switches

Micro switches are used, for example, in control, regulation, precision engineering and on appliances as well as motor vehicles.

Design and mode of operation:

Minimum space requirement, high switching capacity and robust design are some of the many advantages of these mirco switches. With the usual international mounting and overall dimensions as well as a selection of various methods of connection, the switches can be universally applied.

The micro switches are available with snap or slow action.

A large variety of actuators is available.

The switches are protection class IP 30 or 40. Versions are available with “finger-proof” covers. The devices are listed in order of size, starting with the smallest.

Foot Switch

Foot switches are mounted on machines and plants in cases where operation using the hands is not possible. They are used to start and stop operations and production processes.

Depending on the environmental conditions and mechanical duty, differing versions of foot switches are used. The robust foot switches are generally used in the engineering industry, e.g. on presses, punching and bending machines as well as in sheet-steel processing.

Design and mode of operation:

All the foot switches are available in versions with multiple pedals. 232 range switches are mounted with a shield to protect against unintentional actuation.

They have the protection class IP 65 or 67.

Command and Signalling Devices
Range of application:

Command and signalling devices are highly important devices at the man-machine interface in industrial applications. They are used for instance in control cabinets, -on control panels, two-hand controls, in elevator construction or on conveyor and transport plants. After the manual actuation, the components initiate or switch off work processes and functional processes.

Design and operating principle:

Command devices are available in the form of pushbuttons, joystick switches or key-operated switches. The actuators are connected to the switching element through a bayonet socket.

Shaft Encoder