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BN 20

Operating instructions

Magnetic reed switches

EN

1

1.  About this document

1.1  Function

This operating instructions manual provides all the information required 

for the mounting, set-up and commissioning to ensure the safe opera-

tion and disassembly of the safety switchgear. The operating instruc-

tions must be available in a legible condition and a complete version in 

the vicinity of the device.

1.2  Target group: authorised qualified personnel

All operations described in this operating instructions manual must 

be carried out by trained specialist personnel, authorised by the plant 

operator only.

1.3  Exclusion of liability

For safety reasons, invasive work on the device as well as arbitrary 

repairs, conversions and modifications to the device are strictly 

forbidden; the manufacturer shall accept no liability for damages 

resulting from such invasive work, arbitrary repairs, conversions and/or 

modifications to the device.

1.4  General safety instructions

The user must observe the safety instructions in this operating 

instructions manual, the country specific installation standards as well 

as all prevailing safety regulations and accident prevention rules.

2.  Product description

2.1  Ordering code

This operating instructions manual applies to the following types:

BNS 20-

Z

No. Option

Description

01

1 NC 

02

2 NC 

10

1 NO

20

2 NO

11

1 NC contact / 1 NO contact

R

1 bistable contact

2R

2 bistable contact

11R

2 bistable contact NC / NO

2.2  Special versions

For special versions, which are not listed in the order code below 2.1, 

these specifications apply accordingly, provided that they correspond to 

the standard version.

2.3  Purpose

The magnetic reed switches BN 20 with two contacts are designed to 

monitor the position of movable safety guards according to ISO 14119. 

The magnetic reed switch is classified as uncoded switchgear 

type 3 in accordance with ISO 14119. 

Only the listed magnets may be used for actuation of the magnetic reed 

switch. Only these magnets can guarantee flawless function and repeat 

accuracy. With suitable evaluation and concealed installation, the 

requirements for safety applications up to PL e in accordance with  

ISO 13849-1 can be satisfied.

2.4  Technical data

Standards: 

IEC 60947-5-1

Enclosure: 

AlSi 12 die-casting, painted

Protection class: 

IP67 to IEC 60529

Operating principle: 

magnetic

Cable entry: 

2x M16

Connection: 

screw terminals

Switching voltage: 

max. 250 VAC/DC

Switching current: 

max. 3 A

Switching capacity: 

max. 120 VA/W

Dielectric strength: 

> 600 VAC (50 Hz)

Actuating speed: 

max. 18 m/s

Switching frequency: 

max. 300/s

Switching time “Close”: 

0.3 ms … 1.5 ms

Switching time “Open”: 

max. 0.5 ms

Bounce duration: 

0.3 ms … 0.6 ms

Ambient temperature: 

– 25 °C … + 90 ºC

Mechanical life: 

10

9

 operations

Electrical life: 

10

6

 … 10

9

 operations, depending on load

Resistance to vibration: 

50 g on sine wave oscillation

Switching point accuracy: 

± 0.25 mm, T = constant

Resistance to shock:

 

30 g / 11 ms

Tightening force:

 

 

- Cover screws:

 

min. 0.6 Nm 

- Cable gland:

 

min. 1.2 Nm 

- Blocking screws:

 

min. 1.2 Nm

B

10D

 to ISO 13849-1: 

 

- NC contacts (at 20 % contact load): 

20,000,000  

- NO contacts (at 20 % contact load):

 20,000,000

Further technical information can be found in the Schmersal 

catalogues or in the online catalogue on the Internet:  

www.schmersal.net.

The information contained in this operating instructions manual is 

provided without liability and is subject to technical modifications.

3.  Mounting

3.1  General mounting instructions

When mounting to protective equipment, the requirements of 

standard ISO 14119 must be taken into account.

Two elongated holes are available for fastening the enclosure.

Any mounting position, provided that the active surfaces are opposite

Magnetic reed switches and actuators 

• Do not use as limit stops.

• Do not install in strong magnetic fields.

• Do not install on ferromagnetic material.

• Do not expose to strong vibrations or shocks.

• Inseparably fix to the safety guard.

The use of a protective ground wire is imperative.

 Keep away from metal chips

x.000 / 08.2018 / v

.A.   -   103027237-EN / 

A / 2018-08-22 / 

AE-Nr

. -

EN

Operating instructions. . . . . . . . . . . . .pages 1 to 2

Original

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