Rockwell Automation 871TM Extended Range User Manual User Manual

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871TM Extended Range User Manual

OUNTING

ONSIDERATIONS

Mounting considerations for shielded 871TM Extended Range units are essentially identical to those

of any inductive proximity sensor. The unshielded models, however, require special mounting

considerations as a result of their response to nonferrous metals. Due to the unusually long sensing

ranges of the 871TM Extended Range, the sensing field extends farther back on the barrel and has

a wider diameter than typical devices. This increased field requires any metal mounting hardware be

placed as far back on the sensor barrel as possible to avoid interference and false triggering. When

selecting mounting hardware the recommended bracket materials are stainless steel or plastic—

especially in the case of the 30mm units. For assistance determining the best mounting hardware for

your application, consult your Rockwell Automation representative.

AGNETIC

IELDS

All inductive proximity switches are affected by external alternating magnetic fields whose

frequencies lie close to the sensor’s operating frequency. Unlike standard inductive proximity

sensors whose operating frequencies lie in the region of a few 100kHz, the 871TM Extended Range

family operates in the area of a few kHz. In particular, 50Hz magnetic fields with high harmonic

content, such as stray fields from mains transformers as well as nearby stepping motors, can lead to

problems with the 871TM Extended Range. However, the potential for these sensors to be

influenced by switching power supplies (induction heaters, for example) is significantly lower.

Permanent magnetic fields and low frequency alternating fields (50/60 Hz) with low harmonics

content are permissible up to a field strength of 1,000A/m (30mm barrel diameter—80 A/m).

IQUIDS

Due to their one-piece stainless-steel construction, the 871TM Extended Range family of inductive

proximity sensors is naturally suitable for applications where liquids are present. Cable units are

virtually impermeable from a construction standpoint; however, the PUR cable used can have

limitations when faced with various chemicals. The same is true for micro QD models in most cases,

however, some manufacturers’ cordsets may have a missing or unsuitably dimensioned O-ring on

the connector side causing an unstable seal. For this reason, cable models are strongly

recommended in applications where sealing is crucial. To determine the best cabling option for your

application, consult your local Rockwell Automation representative.

www.rockwellautomation.com

Power, Control and Information Solutions Headquarters

Americas: Rockwell Automation, 1201 South Second Street, Milwaukee, WI 53204 USA, Tel: (1) 414.382.2000, Fax: (1) 414.382.4444
Europe/Middle East/Africa: Rockwell Automation, Vorstlaan/Boulevard du Souverain 36, 1170 Brussels, Belgium, Tel: (32) 2 663 0600, Fax: (32) 2 663 0640
Asia Pacific: Rockwell Automation, Level 14, Core F, Cyberport 3, 100 Cyberport Road, Hong Kong, Tel: (852) 2887 4788, Fax: (852) 2508 1846

Publication 871TM--UM001A--EN--P – February 2004