Ййй йй йй йй йй йй йй ййй ййй ййй ййй ййй ййй – Rockwell Automation 871TM Inductive Proximity Sensor User Manual

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CAUTION; Solid state devices can be susceptible to radio frequency (RF) interference, depending on the

frequency of the transmitting source. If RF transmitting equipment is to be used in the vicinity of the solid state

devices, thorough testing should be performed to assure that the transmitter operation is restricted to a safe

operating distance from the control equipment and wiring.

INSTALLATION INSTRUCTIONS

3 Sn

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EFFECTS OF NEARBY METAL SURFACES

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Sensors embedded in metal

Shielded

Sensors not embedded in metal

Not shielded

Sn = rated operating distance

d = diameter of sensing surface

SPACING BETWEEN SENSORS

Sensors embedded in metal

Shielded

Sensors not embedded in metal

Not shielded

d = diameter of sensing surface

WARNING: Do not let METAL objects that
are not to be sensed come within three
times the sensing distance of this device.
Unintended process activation may result
in a hazardous condition.

SENSING DISTANCE

CORRECTION FACTORS

Steel

1.0

Stainless Steel

0.9 to 1.0

Brass

0.3 to 0.5

Aluminum

0.1 to 0.4

Aluminum

≤

.012 thick

0.9 to 1.1

Copper

0.4 to 0.6

The standard target is a square of mild steel

(ST37), 1mm thick. The side of the square

is equal to the diameter of the sensor or

three times the sensing distance, whichever

is larger. Targets smaller than standard size

may shorten the sensing distance. Targets

larger than standard may lengthen the

sensing distance.

To determine the sensing distance for

materials other than the standard mild steel,

multiply the sensing distance by the factor

given below:

SERIES CONNECTED SWITCHES

PARALLEL CONNECTED SWITCHES

When connected in series, the operating

load voltage must be less than or equal to

the minimum supply voltage, minus the

voltage drops across the proximity switches

connected in series. The load will energize

when the connected outputs of all proximity

switches are energized.

To determine the maximum number of

switches for an application, the sum of the

maximum OFF-state currents of the

switches connected in parallel must be less

than the maximum OFF-state current of the

load device. The load will be energized when

the output of any proximity switch energizes.

NOTE: Parallel operation of switches does

not provide higher load current capability

and may generate a false pulse" under

certain conditions.

IMPORTANT: Save these instructions for

future use. For additional information and

proper operating guidance, refer to the

Allen-Bradley Proximity Catalog 871-1.2 or

the product data sheet 871TM-2.0

When installing side by side, the minimum spacing
distance should be maintained. When mounting face
to face, use two times the diameter.

Metals immediately opposite the sensing face should
be no closer than three times the rated operating
distance of the sensor.

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Metal free

zone

3 Sn

≥