Replaces Reed Switches
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GMR technology for accuracy and response time for fast traveling pistons

ifm's line of magnetic sensors for cylinders incorporates Giant Magnetoresistive (GMR) technology which provides enhanced performance and extreme durability in industrial automation applications. With the utilization of this technology, ifm cylinder sensors provide the highest accuracy and response time for cylinder sensing applications.

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GMR sensor element



A GMR sensor element is made up of thin stacked layers of alloy and conductive non-magnetic materials. When these materials are exposed to a magnetic field, there is a large drop in resistance. The sensor element utilizes this physical property to generate a signal that can be used to indicate the position of a magnetic target.
 

Technology comparison

GMR technology has significant advantages over reed switch technology

    Reed GMR GMR Advantages
Durability Low (1-2 M cycles) High (unlimited cycles) GMR cylinder sensor has unlimited number of cycles. Typically, a reed switch is replaced many times during the life of a cylinder.
Repeatability Low High Provides excellent repeatability. Mechanical wear in reed switches can cause the switch point to drift.
Response Time Low High Fast response time. Reed switches with slower response times cannot maintain their accuracy in high speed applications.
Sensitivity Low High Can operate reliably with weak magnetic fields. Reed switches require great magnetic strength for sensing.
Temperature Stability High High Extremely stable operating characteristics over a wide temperature range.
Longevity Low High Immunity from long-term effects of magnetic fields. Contacts on reed switches can become permanently magnetized over time.