Level I Level I

1

Training Series: Level ITraining Series: Level I

2

Electrical InterfaceElectrical Interface

The Back-end

3

Electrical InterfaceElectrical Interface

Divided into 2 areas:◦Operating voltage

◦Output signal type

Electrical InterfaceElectrical Interface

PowerPower

SignalSignal

4

OUTPUT SIGNAL TYPES

Discrete ON or OFF YES or NO

Analog Speed control Position information

MIN MAX

Electrical InterfaceElectrical Interface

SignalSignal

5

OPERATING VOLTAGE

Direct Current (DC) Current flows in only

ONE direction Safe, easy-to-handle

power source

Alternating Current (AC) Current changes direction

60 times a second Readily available

Electrical InterfaceElectrical Interface

PowerPower

6

A DISCRETE SENSOR IS A SWITCH

Electronics

Sensing SideFront-end

Electronics

Power WiresSwitch

Electrical InterfaceElectrical Interface

7

Electronics

BASIC SENSOR CIRCUIT

Sensors with relay output

+

-

Unlike a switch, sensors require power to operate

Electrical InterfaceElectrical Interface

8

TYPES OF DISCRETE ELECTRICAL OUTPUTS

Sensors of today use Solid-State outputs, not mechanical relays

Today Yesterday PNP, 3-wire Relay NPN, 3-wire AC/DC, 2-wire

Electrical InterfaceElectrical Interface

9

THE NPN & PNP OUTPUT

Functions similar to a switch,But current only flows in one direction

PNPTransistor Mechanical

Switch

Electrical InterfaceElectrical Interface

10

THE DIFFERENT TRANSISTORS

What direction do you want current to flow?

NPNAlso called Sinking

Electrical InterfaceElectrical Interface

PNPAlso called Sourcing

+--+

11

PNP, 3-WIRE

1

4+

PNP Output3 -

Load

Standard diagram formAs shown in our catalog

The Sensor

The LoadConnector

Pins

Electrical InterfaceElectrical Interface

12

PNP, 3-WIRE

1

4+

PNP Output3 -

Load

Watching the current flow

Sensors Power

Output Signal

Electrical InterfaceElectrical Interface

13

1

4+

NPN Output3 -

Load

NPN, 3-WIRE

Watching the current flow

Sensors Power

Output Signal

Electrical InterfaceElectrical Interface

14

1 ~

3 ~

Load

THE 2-WIRE AC/DC OUTPUT

Functions similar to a switch,But with a small leak

Sensors Power Supply from leakage current

Output Signal

Triac

Electrical InterfaceElectrical Interface

15

QUICK REFERENCE:WIRING PNP & NPN

N P NP N P

+

-

Load

First s

ide of load

Second side of lo

ad

Switched sid

e

Positive

Negative

Sensor is PNP

Electrical InterfaceElectrical Interface

16

IF GIVEN A CHOICE, WHICH DISCRETE SENSOR TYPE SHOULD I CHOOSE?

PNP or NPN, 3-wire

- Fewer interface problems

- Largest selection- Lowest unit costs

AC/DC, 2-wire- Many interface

issues- Smaller selection- Susceptible to noise

1st CHOICE

2nd CHOICE

1

4+

3 -

Load

1 ~

3 ~

Load

Electrical InterfaceElectrical Interface

17

NORMALLY OPEN (NO)VS. NORMALLY CLOSED (NC)

Identifies the non-active state (target not present) of the sensor

Electronics

+

-

Normally Open

Is it off (open)?

Is it on (closed)?

Electrical InterfaceElectrical Interface

18

NORMALLY OPEN (NO)VS. NORMALLY CLOSED (NC)

Identifies the non-active state (target not present) of the sensor

Electronics

+

-

Is it off (open)?

Is it on (closed)?

Electronics

+

-

Normally Closed

Electrical InterfaceElectrical Interface

19

ANALOG OUTPUTS

Unlike a discrete output with two defined states, analog signals have an infinite number of states.

Discrete

Analog

On

Off

Voltage

Time

Max

Min

Voltage

Time

Electrical InterfaceElectrical Interface

20

ANALOG USES

To provide absolute measurement or position information

MeasurementPosition

Electrical InterfaceElectrical Interface

21

ANALOG APPLICATIONS!

Spool diameter Rotational position Liquid level Sort parts Determine part

orientation Measure vibration Measure straightness Hydraulic or pneumatic

cylinder position

Expandingpossibilitie

s

Expandingpossibilitie

s

Electrical InterfaceElectrical Interface

22

ANALOG DATA

0 10987654321

Measurement

Panel meters Control systems

Electrical InterfaceElectrical Interface

23

ANALOG INFORMATION

The many forms for representing measurement or position information

10

0

10

-10

5

-5

20

0

20

4

Voltage

Current

Digital Pulse

Electrical InterfaceElectrical Interface

24

ANALOG VOLTAGE

Information contained in varying voltage

Maximum Voltage

0 10987654321

Measurement

Half VoltageNo Voltage

0 10987654321

Measurement

0 10987654321

Measurement

Water Analogy Volt Meter

Electrical InterfaceElectrical Interface

25

ANALOG CURRENT

Information contained in varying Current

0 10987654321

Measurement

0 10987654321

Measurement

0 10987654321

Measurement

Maximum CurrentHalf CurrentNo Current

Water Analogy Current Meter

Electrical InterfaceElectrical Interface

26

DIGITAL PULSE

Information contained in digital pulse timing

100.00Maximum

measurementHalf wayMinimum

measurement50.000.00Pulse Width

Meter

Start/Stop

Electrical InterfaceElectrical Interface

27

ELECTRICAL INTERFACE REVIEW

Operating voltage: Sensor PowerDC: SafestAC: Most available

Output signal typesDiscrete

PNP, 3-wire NPN, 3-wire AC/DC 2-wire

Analog Voltage Current Digital pulse

Electrical InterfaceElectrical Interface

PowerPower

SignalSignal