The inductive linear transducers IWN250 are contactless, wear-free and robust. They operate according to the principle of the differential choke (i.e. an inductive half bridge or LVDT) and consist of two coils, which are encapsuled in a stainless steel cylinder. A ferronickel plunger core causes opposing changes of inductance when it is displaced through the centre of the coils. These changes are converted by the integrated electronics into an analog signal proportional to the displacement. This signal is further processed with a 12 bit A/D-converter and provided to the bus via a microprocessor with integrated CAN interface. The measuring direction is programmable by the customer.
Mechanical versions with ball joints on the plunger either/or on the case and gauge types with return spring exist. Customer-specific solutions with different housings, connectors or special software for example can be realized. So a smaller transducer (diameter 10 mm, length 20 mm for a measuring stroke of up to 8 mm) with external electronics was designed.
Besides CANopen the inductive transducers are available with SSI or analog output (0(4) mA to 20 mA, 0 V to 10 V, ±10 V).

The main features of the IWN250 are

• Measuring stroke: 20 mm, 40 mm, 100 mm or 200 mm
• Linearity: 0,5 % or 0,25 %
• Resolution: 12 bit at full scale
• Measuring direction programmable
• Protection grade: IP66
• Temperature: −10 °C to +80 °C
• Device profile: CiA 406 version 3.0

Besides the inductive linear transducers TWK offers also magnetostrictive linear transducers in two different designs (profile or rod). These transducers are available for longer measuring strokes (up to 7 600 mm), with higher linearities (up to 0,01 %) and with the possibility to measure up to four positions simultaneously.