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CompanyInformatio

SystemsOverview

ProgrammController

Field I/O

Software

C-more &other HM

Drives

SoftStarters

Motors &Gearbox

Steppers/Servos

MotorControls

Proximity

Sensors

PhotoSensors

LimitSwitches

Encoders

CurrentSensors

PressureSensors

TemperatuSensors

PushbuttoLights

Process

Relays/Timers

Comm.

TerminalBlocks &Wiring

Power

CircuitProtection

Enclosure

Tools

Pneumati

Appendix

ProductIndex

Part #Index

Volume 13

How do inductive proximityswitches work?

Inductive proximity switches are used todetect the presence of metallic objects

without actually contacting the object.Their high-speed switching and small sizemake them indispensable in automationapplications.

Inductive proximity switches consist of acoil driven by an oscillator. The oscillatorcreates an electromagnetic field whichappears at the active face of the switch. Ifa metal target enters this area, the electro-magnetic field is reduced and the switchturns on or off.

Some typical inductive sensor applicationsare: counting metallic objects, monitoringthe position of elements in a machine,

sensing the presence of metallic parts likescrews, etc., and measuring the rotationalspeed of axial detecting cams.

What is the difference betweeninductive and capacitive sensors?

The primary difference is sensing material.Inductive sensors only detect metallicobjects while capacitive sensors will detectmaterials such as wood, paper, liquids,cardboard, etc.

How do I know what size proximity

sensor I need?It depends on two factors: mounting spaceand sensing distance. Each applicationhas a specific space available for thesensor and each application has arequirement for how close the sensor canbe mounted to the sensed object.

What is the difference betweenshielded and unshielded?

With a shielded proximity sensor, the faceof the sensor may be mounted flush withmetal, whereas an unshielded sensor may

NOT be mounted flush with metal (other-wise the sensor will always be ON). Inmany applications, flush mounting is arequirement. Also, unshielded proximitysensors allow for greater sensingdistances.

What output do I need?NPN or PNP?

This is determined by the device you areconnecting the sensor to. MostDirect

LOGIC PLC modules (except 305series) allow NPN or PNP sensors to beconnected. This is determined by how thesensor is wired to the PLC.

How do I choose between normallyopen (N.O.) and normally closed(N.C.)?

N.O. sensors do not pass power to thePLC until an object is detected. N.C.sensors always pass power to the PLC untilan object is detected. The majority ofCentsable sensors are N.O.; however,some sensors offer the option of N.C.,such as PKW, PMW and CT1 series.

When do I want quick disconnects(Q/D) versus embedded cableoutput?

There is a slight cost increase to purchasea sensor and a Q/D cable compared toonly purchasing a sensor with a pre-attached cable. However, the Q/D outputallows easy replacement of a failed sensor.This is important in minimizing machine oroperation downtime.

What is the difference between 2-wire, 3-wire, and 4-wire sensors?

2-wire sensors: allows either NPN or PNPoutputs (don't have to select).

3-wire sensors: standard sensors. Whenordering, you must choose between NPNand PNP output.

4-wire sensors: Allow either N.O. or N.C.outputs (don't have to select). Must stillselect NPN or PNP output.

Do AutomationDirect suppliedsensors operate on AC or DCvoltage?

The majority of AutomationDirect supplied

sensors operate on 10-30 VDC. However,we do offer the VT1, VK1, and VM1 seriesthat operate on 20-253VAC.

Can my sensor be installed in awashdown area?

Yes. All AutomationDirect supplied prox-imity sensors carry an IP67 or IP68 enclo-sure rating. This rating allows temporarysubmersion of the sensor into water.

What does switching frequencymean to my application?

This is how fast your sensor can sense anobject, reset, and sense another object.For example, if a sensor has a switchingfrequency of 100 Hz or 100 cycles persecond, the sensor can sense a maximumof 100 objects per second. This is very crit-ical in many applications such as gearrotation measurement.

Can the sensor be put into avibrating environment?

Yes. Frequency range of 10-55 Hz,maximum amplitude of 1mm. Duration in

any axis a maximum of 30 minutes.

What is the temperature range ofthe sensors?

Most sensors operate between -25F and70F. However, check the specificationsfor exact ranges.

If I wire my proximity sensor wrong,will it damage it?

Possibly. All sensors contain polarityreversal, short-circuit and transient noiseprotection. However, the transient protec-tion is only effective under 30 VDC.

Frequently Asked Questions