Rotary Limit Switch


The rotary limit switch is a device, which allows you to control the movement of industrial and building machines. The shaft is connected to the motor, so that, after a certain number of turns, the cams make the switches work, and then they can carry out their pre-set manoeuvre.

The innovative and thorough regulation of the cams allows you to set the microswitches working point linearly and micrometrically.The limit switch ranges several ratios and you can assemble different kinds og sensors realizing varios linear outputs. Contacts are positive-opening, which improves the workers’ safe.

This series includes a great number of different accessories, which make easier the use of the limit switch.

  • Technical Features
  • Standards
  • Models
  • Accessories
  • Spare Parts
  • Download

Main Features

  • Insulation voltage 250V~
  • Maximum operating voltage 250V~
  • Black lower casing reinforced nylon
  • Yellow cover high mechanical and thermal resistant thermoplastic
  • Operating temperature - 20 °C + 60 °C
  • Drive worm screw
  • Cable entries standard: 2 glands M20x1,5 (option more glands)
  • Protection against contact voltages double insulation
  • Weight 460 g (approx.)

Contact and Regulation Cams

Regulation criteria:

Each cam is equipped with its own adjusting screw micrometer. The adjustment is made simply using a screwdriver.

Adjusting fast optional
  • oosen the screw top
  • rotate hand cams
  • tighten the top screw (1 Nm torque)
Fine adjustment
  • turn the adjusting screw for each cam
  • Recommended screwdriver 4.0 x 0.8

Contacts Features

Microswitch 1 NA 1 NC rapid positive opening, self cleaning contacts
  T Type blue color (standard)
  R Type white color (fingerproof)
  D Type golden contacts (on request)
Insulation Voltage 250 V~
Test Voltage 2000 V~
Termal Current 10 A
Breaking Power according to EN 60947-5-1
Mechanical Lifetime 2x10 man
Terminals with crews - with fingerproof screw (on demand)

Standard cams profiles

Type A pointed white

Type B sector grey

Type C quarter turn red


Type D semi-turn white

Type E circular white

Type F 10 point white


  • 2006/42/CE
  • 2006/95/CE
  • 2002/95/CE

  • CEI EN 60947-1
  • CEI EN 60947-5-1
  • CEI EN 60204-1
  • CEI EN 60529
  • CEI EN 60439-1
  • UL508 Industrial Control Equipment

  • IP 66

Standard Execution

FRM limit switch is equipped with 3 internal rotation axes, named:
  • OUT 1 output for different ratios 1:n
  • OUT 2 output for different ratios 1:n o 1:k
  • OUT 3 output for direct ratio 1:1

It’s possible to use mex 2 internal rotary axes simultaneously: OUT 1 is always available, while either OUT 2 or OUT 3 can be used (they cannot be used at the same time).

The fourth rotation axis OUT L is available for the application of a speed reader. Some printed, pre-wired circuits, provided with terminal blocks, can be inserted, on demand, to help the connections between the internal components.

Standard Ratios

1:1 direct ratio OUT 3 for sensors

1: 1 - 5 - 15 - 25 - 50 - 75 - 100 - 150 - 200 - 300 up to 900 for either OUT 1 or OUT 2. 

Several ratios are available on demand and according to the requestes quantity. Standard executions are with 2,4,6 contacts; executions with 3,8,10,12 contacts are availabe in consideration of the quantity.

Customized Executions

The FRM limit switches are available in special executions for quantities. In particular it is possible to provide
  • Shaft of different lenghts
  • Twin-shaft executions
  • Different kind of contacts
  • Front or lateral gland
  • Cams with various profiles
  • Customized labels

Accessories Range

The series ranges several accessories, which make easier the use of the limit switches, and meet some particular needs. A number of cog wheels, the male shaft and the flexible shaft have been studied to convey easily the motion from the shaft of the motor to the shaft of the limit switch. The application of encoders, potentiometers or some other sensors, in addition to the groups of microswitches, produces in the same device an analogic or digital ouput, which can be properly read.

Cog Wheels

A number of cog wheels, the male shaft and the flexible shaft have been studied to convey easily the motion from the shaft of the motor to the shaft of the limit switch.

Available modules:
  • 5 module with 12 tooth
  • 6 module with 11 tooth
  • 8 module with 12 tooth
  • 10 module with 12 tooth
  • 14 module with 10 tooth
  • 16 module with 10 tooth
  • 18 module with 10 tooth
  • 18 module with 11 tooth
  • 20 module with 8 tooth
  • 20 module with 11 tooth

Male Connection

The male connection helps the joining to motors or reducing gears.

Flexible Shaft

The flexible shaft allows you to couple the shafts that are not perfectly aligned.

Attachment Flange

The flange interface allows the limit switch to be fixed without the special fixing plate.

Other Features

  • Speed Reader
  • Connection board
  • Golden Contacts
  • Finger-proof contacts
  • -40°C Version
  • UL Version

Order Codes

B FRM xxx y NN z
Group Series Reduction Ratio Contact Type Contact numbers Cam Type

Spare Parts and Accessories

Position Code Description
1 B51792 Cover up to a 4 micro
B51793 Cover for 5-6 micro
2 BT11FR Contact T 1 NA 1 NC rapid blue (standard)
BR11FR Contact R 1 NA 1 NC rapid white (fingerproof)
BD11FR Contact D 1 NA 1 NC golden (on demand)
3 BCAMAFR Cam A - pointed
BCAMVFR Cam B - sector
BCAMCFR Cam C - semi-turn
BCAMDFR Cam D - quarter-turn
BCAMEFR Cam E - circular

Cam F - 10 point

Position Code Description
4 BMOD5FC Cog Wheel M5Z12
BMOD6FC Cog Wheel M6Z11
BMOD8FC Cog Wheel M8Z12
BMOD10FC Cog Wheel M10Z12
BMOD12Z10 Cog Wheel M12Z10
BMOD12Z12 Cog Wheel M12Z12
BMOD14FC Cog Wheel M14Z10
BMOD16Z10 Cog Wheel M16Z10
BMOD18Z10 Cog Wheel M18Z10
BMOD18Z11 Cog Wheel M18Z11
BMOD20Z8 Cog Wheel M20Z8
BMOD20Z11 Cog Wheel M20Z11
6 BAFLESFC Flexible Shaft
7 BINNFC Male connection
8 - Potentiometer (on request)
9 -

Encoder (on request)

Other sensor (on request)

10 - Supports for sensors assembly (on request)
11 - Speed Reader (on request)
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