Dwyer PS User Manual

Bulletin E-81-PS

Series PSC/PSI Proximity Sensors

Specifications – Installation and Operating Instructions

INTRODUCTION - Proximity Sensors

The Proximity Controls range of proximity sensors includes induc­tive and Capacitive proximity switches and a Test unit. These are
listed and stocked in our catalog for fast service. Should you need
a non-listed varient please contact the sales office.
Inductive (PSI) switches will detect all metals. Capacitive (PSC)
switches will detect nearly all solids, powders and liquids. The A­800 Test Unit will give a functionality test to all versions stocked in
the catalog and will test most three wire DC proximity switches
from other manufacturers.

SENSING DISTANCE

Sensing ranges refer to a 1 mm thick square target of earthed mild
steel with sides of 3 x the nominal sensing distance. If the target
is a different material, or of another size, there will be a variation
in the sensing distance.

MATERIAL

Mild Steel
Cast Iron
Aluminum Foil
Stainless Steel
Brass
Aluminum
Copper
Water
PVC
Glass
Ceramics
Wood
Beer
Coca Cola
Lubricating Oil

MATERIAL FACTORS

INDUCTIVE

1.0

1.1

0.9

0.7

0.4

0.35

0.3

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

CAPACITIVE

1.0

1.0

1.0

1.0

1.0

1.0

1.0

0.9

0.9

0.5

0.4
from 0.2

0.9

0.9

0.1

INSTALLATION (MECHANICAL)
Flush Mounting

Units designed for flush mounting, including all inductives listed in
the catalog, may be fitted in surrounding metal as shown.

NOTE: Capacitive switches can, if required, be tuned down to be
fitted flush in metal. See section on sensitivity adjustment.

INSTALLATION (ELECTRICAL)
Single Units

DC units have transistor output, and normally have three wires,
but NAMUR standard DC sensors have only two wires.

3 Wire DC Switch

2 Wire DC Sensor

Note that units with two wires must be connected to their power
supply with a load in series, or they will be damaged. Consult cat­alog for load rating.

Logic Interface

Proximity sensors may be interfaced with most types of industrial
logic. Most DC units are open collector type and therefore require
an external pull up resistor when used with TTl as shown.

Flush Fitting

Non-Flush Mounting

Units designed for non-flush mounting, including Capacitive
switches, must be separated from teh surrounding metal as
shown.

Non Flush

Fitting

A= Not Less

Than 3d

PROXIMITY CONTROLS

A DIVISION OF DWYER INSTRUMENTS, INC.

P.O. BOX 373 • MICHIGAN CITY, INDIANA 46361, U.S.A.

Note that 3 wire DC-Compact V3 bodied switches are designed for
use directly with TTL and have a built-in pull up resistor.

Multiple Units: Parallel

DC sensors may be connected directly in parallel as in shown. The
number (N) of switches is usually only limited by the availability of
sufficient supply current. Note that the compact V bodied switches
have an internal pull-up resistor with a resistance of 12 kilohms.
The maximum number of compact switches in parallel is:
N=Rating Load Current (mA) x 12 Kilohm / V supply.

Phone: [phone] www.dwyer-inst.com
Fax: [phone] e-mail: [e-mail]

Multiple Units: Series

The maximum number of DC sensors connected in series is limit­ed by the supply voltage (V supply), the voltage drop across a
closed switch (V switch) and either the minimum working voltage
of the switch or minimum working voltage of the load, whichever is
greater (V min).

The diagram above shows a typical series configuration of PNP
sensors. For NPN types, swap the blue for brown wire and recon­nect.

GENERAL INFORMATION
LED Indicators

Most Proximity sensors are fitted with indicator lights (LED’s) at
the cable end. The LED indicates the state of the switch output.

Maximum Voltage

The maximum voltage of DC proximity sensors is 30 V. It is some­times forgotten that a rectified 24 VAC supply has a peak value of

1.4 X the AC RMS value (34V).
NOTE: These switches should be installed by competent person­nel only. Please check wiring and supply voltages before switch­ing on. If there are any technical questions regarding installation
or application of Proximity sensors please contact the technical
sales department.

A-800 DC Proximity Switch Test Unit

The A-800 is fitted with two PP3 batteries ready for use. This unit
will test most 3 wire DC proximity switches PSI (metal sensing),
PSC (most materials), the magnet sensing Detector (DT), photo­electrics or ultrasonics.
Standard color coding for 3 wire Proximity switches is
Brown=Positive (+), Black=Load, Blue=Negative (–). Note: Some
universal DC switches can vary. Follow the maufacturer’s wiring
instructions.

Testing Instructions

Connect the switch to the A-800. Place a suitable target in front of
the switch. If it is functioning correctly, the test unit will give audio
and visual indication showing that the switch operates and indicat­ing functionality of the switch according to the chart below.

SENSITIVITY ADJUSTMENT
Inductive Switches

Inductive PSI sensors are not adjustable.

Capacitive Switches

Install the capacitive PSC sensor in its final position. Remove the
black cover screw to gain access to the adjustment potentiometer.
Turn the adjusting potentiometer clockwise to increase sensitivity
or counterclockwise to reduce sensitivity. For example, the range
and sensitivity of capacitive sensors can be adjusted to tune out
the sidewall of a plactic container or glass window of a signt glass
such that the level of liquid, granules or powders on the other side
of the plastic or glass can be detected.
For this application tune out the sight glass or wall with the con­tainer empty, detune the sensor so it cannot see the window or
wall. Then test the settings by introducing the target material
inside the container. Caution should be taken with materials that
leave a residue inside the container as this may be sensed.

NOTE: To maintain the IP65 rating on capacitive sensors, it is
imperative that the black cover screw be replaced after adjust­ment.

SWITCH TYPE

PNP N.O.
PNP N.C.
NPN N.O.
NPN N.C.

BUZZER & LED ON WHEN

Target in range
Target not in range
Target in range
Target not in range

LED

PNP
PNP
NPN
NPN

A-800 DC TEST UNIT

If the Proximity switch does not give such feedback when correct­ly connected to the tester, it has probably failed. NOTE: The A-800
will not test 2 wire AC or DC switches.

LED Functions

Green I/O LED Switch connected and unit on
Red (Battery) LED Battery low indicator
PNP or NPN LED Indicated switch type

Further Information:

Proximity is a Division of Dwyer Instruments, Inc. For further infor­mation, a copy of our latest catalog, other products or details con­cerning our nearest distributor please call our sales office.