Proximity switch

A proximity switch, for detecting whether a detected object exists in a specific range through proximity of the detected object containing metal, the proximity switch comprising:

• a detection part, detecting a physical quantity which is changed according to a distance to the detected object;
• a comparison part, comparing the detected physical quantity with a threshold set for the physical quantity corresponding to a boundary of the specific range, and outputting a detection signal of the specific range when the detected object exists in the specific range;
• a threshold setting part, selecting a threshold corresponding to a metal type designated according to a designation on the metal type from the outside;
• and
• an oscillation circuit, oscillating to generate a high frequency, wherein an amplitude of the high frequency serving as the physical quantity is attenuated or a oscillation frequency serving as the physical quantity is increased or reduced due to the proximity of the detected object containing metal,
• wherein the detection part detects the amplitude or the oscillation frequency of the high frequency generated by the oscillation circuit, the specific range is a range that the distance to the detected object becomes an excessive proximity detection range in a detection distance, and the comparison part compares the detected amplitude or oscillation frequency of the high frequency with a threshold for excessive proximity detection which is the threshold set for the amplitude or oscillation frequency corresponding to a boundary of the excessive proximity detection range in the detection distance, when he detected amplitude is over the threshold for excessive proximity detection, or when the oscillation frequency detected under the condition that the oscillation frequency is increased along with the proximity of the detected object is under the threshold for excessive proximity detection, or when the oscillation frequency detected under the condition that the oscillation frequency is reduced along with the proximity of the detected object is over the threshold for excessive proximity detection, a signal of being within an excessive proximity range serving as the detection signal of the specific range is output.

A proximity switch, for detecting whether a detected object exists in a specific range through proximity of the detected object containing metal, the proximity switch comprising:

• a detection part, detecting a physical quantity which is changed according to a distance to the detected object;
• a comparison part, comparing the detected physical quantity with a threshold set for the physical quantity corresponding to a boundary of the specific range, and outputting a detection signal of the specific range when the detected object exists in the specific range;
• a threshold setting part, selecting a threshold corresponding to a metal type designated according to a designation on the metal type from the outside;
• and
• one or more detection coils, wherein a voltage serving as the physical quantity is increased due to the proximity of the detected object containing metal, the detection part detects the voltage generated in the detection coil,
• wherein the specific range is a range that the distance to the detected object reaches an excessive proximity,
• the comparison part compares the detected voltage with a threshold for excessive proximity which is the threshold set for the voltage corresponding to a boundary of the excessive proximity, when the detected amplitude is over the threshold for excessive proximity, an excessive proximity detection signal serving as the detection signal of the specific range is output.

A proximity switch, for detecting whether a detected object exists in a specific range through proximity of the detected object containing metal, the proximity switch comprising:

• a detection part, detecting a physical quantity which is changed according to a distance to the detected object;
• a comparison part, comparing the detected physical quantity with a threshold set for the physical quantity corresponding to a boundary of the specific range, and outputting a detection signal of the specific range when the detected object exists in the specific range;
• a threshold setting part, selecting a threshold corresponding to a metal type designated according to a designation on the metal type from the outside;
• and
• one or more detection coils, wherein a voltage serving as the physical quantity is increased due to the proximity of the detected object containing metal, the detection part detects the voltage generated in the detection coil,
• wherein the specific range is a range that the distance to the detected object becomes an excessive proximity detection range in a detection distance, and
• the comparison part compares the detected voltage with a threshold for excessive proximity detection which is the threshold set for the voltage corresponding to a boundary of the excessive proximity detection range in the detection distance, when the detected voltage is under the threshold for excessive proximity detection, a signal of being within the excessive proximity range serving as the detection signal of the specific range is output.