Reed Relays and
Electronics India Limited
Manufacturer of Reed Switches, Reed Sensors and Reed-based products
Reed Relays and Electronics India Limited Incorporated in 1971
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Actuation Distances for UM-0018-M Reed Switches

For easy selection of AT band and Magnet for an application, we offer Actuation distances for the UM-0018-M Reed Switch in cropped, SMD, and Horizontal Mount formations. The various combinations of standard AT Bands and magnets are covered, from the lower AT bands to the higher AT bands. Each AT band lists distances when actuated with our standard magnets. Although some of the AT band / magnet combinations will produce similar actuating distances, selecting the right AT band and magnet for an application is important. All distances given are in mm and standard tolerances of ±0.5 mm apply.

Activation Distances for UM-0018-M Cropped

Drawing of UM-0018-M reedswitch cropped
All dimensions in mm

UM-0018-M (7-12 AT)

Actuation Sketch Magnet Dimensions Operate Distance Release Distance
cropped reed switch actuation distance
NDR-T 4.0 x 1.5 x 1.5 2.3 – 3.5 2.5 – 4.0
NDR-S 6.0 x 2.5 x 2.5 6.0 – 7.5 6.5 – 7.0
NDR-M  8.0 x 3.0 x 3.0 8.0 – 9.5 8.5 – 10.0
NDR-L 19.0 x 4.0 x 4.0 13.3  – 17.5 14.0 – 18.0
NDC-T Φ2.0 x 4.0 3.2 – 4.2 3.7 – 5.2
NDC-S Φ3.0 x 7.0 7.0 – 8.0 7.5 – 8.5
NDC-M  Φ4.0 x 10 10.5 – 12.0 11.5 – 13.5
NDC-L Φ8.0 x 15.0 20.5 – 24.0 21.5 – 25.0

UM-0018-M (12-17 AT)

Actuation Sketch Magnet Dimensions Operate Distance Release Di stance
cropped reed switch actuation distance
NDR-T 4.0 x 1.5 x 1.5 2.0 – 2.3 2.3 – 3.5
NDR-S 6.0 x 2.5 x 2.5 5.0 – 6.0 5.5 – 7.0
NDR-M 8.0 x 3.0 x 3.0 7.5 – 8.0 8.0 – 8.5
NDR-L 19.0 x 4.0 x 4.0 13.0 – 13.5 13.5 – 14.0
NDC-T Φ2.0 x 4.0 3.0 – 3.3 3.2 – 4.0
NDC-S Φ3.0 x 7.0 6.5 – 7.0 7.0 – 8.0
NDC-M Φ4.0 x 10 10.0 – 10.5 10.5 – 11.5
NDC-L Φ8.0 x 15.0 20.0 – 20.5 21.0 – 22.0

UM-0018-M (10-15 AT)

Actuation Sketch Magnet Dimensions Operate Distance Release Distance
cropped reed switch actuation distance
NDR-T 4.0 x 1.5 x 1.5 2.0 – 2.5 2.5 – 3.0
NDR-S 6.0 x 2.5 x 2.5 5.5 – 6.5 6.0 – 7.0
NDR-M 8.0 x 3.0 x 3.0 7.5 – 9.0 8.0 – 10.0
NDR-L 19.0 x 4.0 x 4.0 13.0 – 14.0 14.0 – 15.5
NDC-T Φ2.0 x 4.0 3.0 – 3.5 3.5 – 4.0
NDC-S Φ3.0 x 7.0 6.5 – 7.5 7.0 – 8.0
NDC-M Φ4.0 x 10 10.0 – 11.0 10.5 – 12.0
NDC-L Φ8.0 x 15.0 20.0 – 21.0 20.8 – 22.0

UM-0018-M (15-20 AT)

Actuation Sketch Magnet Dimensions Operate Distance Release Distance
cropped reed switch actuation distance
NDR-T 4.0 x 1.5 x 1.5 2.0 – 2.2 2.2 – 2.5
NDR-S 6.0 x 2.5 x 2.5 5.0 – 5.5 5.3 – 6.0
NDR-M 8.0 x 3.0 x 3.0 7.5 – 8.0 8.0 – 8.5
NDR-L 19.0 x 4.0 x 4.0 12.0 – 13.5 12.5 – 14.5
NDC-T Φ2.0 x 4.0 3.0 – 3.3 3.2 – 3.7
NDC-S Φ3.0 x 7.0 6.0 – 7.0 6.5 – 7.5
NDC-M Φ4.0 x 10 10.0 – 10.5  10.5 – 11.0
NDC-L Φ8.0 x 15.0 18.5 – 20.5 19.5 – 21.0

Activation Distances for UM-0018-M SMD

Drawing of UM-0018-M reedswitch for SMD mounting
All dimensions in mm

UM-0018-M (7-12 AT)

Actuation Sketch Magnet Dimensions Operate Distance Release Distance
SMD formed reed switch actuation distance
NDR-T 4.0 x 1.5 x 1.5 3.0 – 3.5 3.5 – 4.0
NDR-S 6.0 x 2.5 x 2.5 7.0 – 7.5 7.5 – 8.0
NDR-M 8.0 x 3.0 x 3.0 8.5 – 10.0 9.0 – 11.0
NDR-L 19.0 x 4.0 x 4.0 14.0 – 17.0 15.0 – 18.0
NDC-M Φ4.0 x 10 10.5 – 13.0 11.0 – 14.0
NDC-T Φ2.0 x 4.0 3.5 – 4.5 4.0 – 5.0
NDC-S Φ3.0 x 7.0 7.0 – 8.5 7.5 – 9.0
NDC-L Φ8.0 x 15.0 21.0 – 25.0 22.0 – 26.5

UM-0018-M (12-17 AT)

Actuation Sketch Magnet Dimensions Operate Distance Release Distance
SMD formed reed switch actuation distance
NDR-T 4.0 x 1.5 x 1.5 2.5 – 3.0 2.0 – 3.5
NDR-S 6.0 x 2.5 x 2.5 6.0 – 7.0 6.5 – 7.5
NDR-M 8.0 x 3.0 x 3.0 8.0 – 8.5 8.5 – 9.0
NDR-L 19.0 x 4.0 x 4.0 13.0 – 14.0 14.0 – 15.5
NDC-T Φ2.0 x 4.0 3.0 – 3.5 3.5 – 4.0
NDC-S Φ3.0 x 7.0 6.5 – 7.5 7.0 – 8.0
NDC-M Φ4.0 x 10 10.0 – 10.5 10.5 – 11.5
NDC-L Φ8.0 x 15.0 20.0 – 21.0 21.0 – 23.0

UM-0018-M (10-15 AT)

Actuation Sketch Magnet Dimensions Operate Distance Release Distance
SMD formed reed switch actuation distance
NDR-T 4.0 x 1.5 x 1.5 2.5 – 3.5 3.0 – 4.0
NDR-S 6.0 x 2.5 x 2.5 6.0 – 7.5 6.5 – 8.0
NDR-M 8.0 x 3.0 x 3.0 8.0 – 9.0 8.5 – 9.5
NDR-L 19.0 x 4.0 x 4.0 13.0 – 15.0 14.0 – 16.5
NDC-T Φ2.0 x 4.0 3.5 – 4.0 3.5 – 4.5
NDC-S Φ3.0 x 7.0 7.0 – 7.5 7.5 – 8.0
NDC-M Φ4.0 x 10 10.0 – 11.0 10.5 – 12.0
NDC-L Φ8.0 x 15.0 20. 0 – 22.0 21.0 – 23.0

UM-0018-M (15-20 AT)

Actuation Sketch Magnet Dimensions Operate Distance Release Distance
SMD formed reed switch actuation distance
NDR-T 4.0 x 1.5 x 1.5 2.5 – 3.0 3.0 – 3.5
NDR-S 6.0 x 2.5 x 2.5 5.5 – 6.5 6.0 – 7.0
NDR-M 8.0 x 3.0 x 3.0 8.0 – 8.5 8.5 – 9.0
NDR-L 19.0 x 4.0 x 4.0 13.0 – 13.5 14.0 – 15.0
NDC-T Φ2.0 x 4.0 3.0 – 3.5 3.5 – 4.0
NDC-S Φ3.0 x 7.0 6.5 – 7.0 7.0 – 7.5
NDC-M Φ4.0 x 10 10.0 – 10.5 10.5 – 11.0
NDC-L Φ8.0 x 15.0 20.0 – 20.5 21.0 – 23.0

Activation Distances for UM-0018-M Horizontal Mount

Drawing of UM-0018-M reedswitch for Horizontal mounting
All dimensions in mm

UM-0018-M (7-12 AT)

Actuation Sketch Magnet Dimensions Operate Distance Release Distance
Goal-post formed reed switch actuation distance
NDR-T 4.0 x 1.5 x 1.5 3.0 – 3.5 3.5 – 4.0
NDR-S 6.0 x 2.5 x 2.5 7.0 – 9.5 7.5 – 10.0
NDR-M 8.0 x 3.0 x 3.0 10.0 – 11.5 10.5 – 12.5
NDR-L 19.0 x 4.0 x 4.0 17.0 – 20.5 18.0 – 22.0
NDC-T Φ2.0 x 4.0 4.0 – 5.0 4.5 – 6.0
NDC-S Φ3.0 x 7.0 8.0 – 9.5 8.5 – 10.0
NDC-M Φ4.0 x 10 12.5 – 15.0 13.0 – 15.5
NDC-L Φ8.0 x 15.0 24.5 – 30.0 25.0 – 31.0

UM-0018-M (12-17 AT)

Actuation Sketch Magnet Dimensions Operate Distance Release Distance
Goal-post formed reed switch actuation distance
NDR-T 4.0 x 1.5 x 1.5 2.5 – 3.5 3.0 – 4.0
NDR-S 6.0 x 2.5 x 2.5 6.0 – 7.5 6.5 – 8.0
NDR-M 8.0 x 3.0 x 3.0 9.5 – 10.5 10.0 – 11.5
NDR-L 19.0 x 4.0 x 4.0 15.0 – 18.0 16.0 – 19.0
NDC-T Φ2.0 x 4.0 3.5 – 4.0 4.0 – 5.0
NDC-S Φ3.0 x 7.0 7.5 – 8.5 8.0 – 9.5
NDC-M Φ4.0 x 10 12.0 – 13.0 12.5 – 14.0
NDC-L Φ8.0 x 15.0 23.0 – 25.0 24.0 – 26.5

UM-0018-M (10-15 AT)

Actuation Sketch Magnet Dimensions Operate Distance Release Distance
Goal-post formed reed switch actuation distance
NDR-T 4.0 x 1.5 x 1.5 3.0 – 3.5 3.5 – 4.0
NDR-S 6.0 x 2.5 x 2.5 6.0 – 7.5 6.5 – 8.5
NDR-M 8.0 x 3.0 x 3.0 9.5 – 10.5 10.0 – 11.5
NDR-L 19.0 x 4.0 x 4.0 15.0 – 17.5 15.5 – 18.0
NDC-T Φ2.0 x 4.0 3.5 – 4.5 4.0 – 5.0
NDC-S Φ3.0 x 7.0 7.5 – 8.5 8.0 – 9.0
NDC-M Φ4.0 x 10 12.0 – 13.0 12.5 – 14.0
NDC-L Φ8.0 x 15.0 23.0 – 25.0 24.0 – 26.5

UM-0018-M (15-20 AT)

Actuation Sketch Magnet Dimensions Operate Distance Release Distance
Goal-post formed reed switch actuation distance
NDR-T 4.0 x 1.5 x 1.5 2.5 – 3.0 3.0 – 3.5
NDR-S 6.0 x 2.5 x 2.5 5.5 – 7.5 6.0 – 8.0
NDR-M 8.0 x 3.0 x 3.0 8.0 – 10.5 8.5 – 11.0
NDR-L 19.0 x 4.0 x 4.0 14.0 – 18.0 14.5 – 19.0
NDC-T Φ2.0 x 4.0 3.0 – 4.0 3.5 – 4.5
NDC-S Φ3.0 x 7.0 7.0 – 8.5 7.5 – 9.0
NDC-M Φ4.0 x 10 10.5 – 13.0 11.0 – 14.0
NDC-L Φ8.0 x 15.0 21.0 – 25.5 22.0 – 26.0

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