mandee liberty & vikram phadke national encoder product specialists : encoders – basic...

Mandee Liberty & Vikram Phadke

National Encoder Product Specialists

: Encoders – Basic Training

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Typical Industrial System

Input Output

Feedback

Controller Operation

(Application)

Sensor

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Encoders within a Control System

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FeedbackSensor

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What is an encoder?: An encoder is a device which converts a mechanical information of a shaft or

position into an electrical signal

Encoder

Encoder Definitions

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Encoder Definitions

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How is this accomplished?: As the code disc rotates, it shutters light from the LED and is received and

transmitted as square\sine waveforms

Receiver / Sensor

Code disc

Lens

Transmitter / LED

Shaft

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Encoder Selection Process

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Encoder Selection Process

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Encoder

Rotary Encoder Linear Encoder

Types of Encoders

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Types of Encoders

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Encoder

Linear Encoder

Wire Draw Linear with Scale

Types of Encoders

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Types of Encoders

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Encoder

Rotary Encoder

Incremental Absolute

Linear Encoder

Wire Draw Linear with Scale

AbsoluteIncremental

Types of Encoders

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Incremental

Produces electrical pulses or incrementswith linear or rotary motion

Signals can be square or sinusoidal waves

Signals start over at power up, or after a power failure. In other words, an incrementalencoder does not retain position after apower cycle

Incremental encoders are typically used forspeed or applications that do not require absolute position

Incremental Encoders

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Absolute Encoders

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Absolute

Provides a unique value for every shaft or linear position

Absolute encoders retain their position after a power cycle

Signals typically use SSI, parallel, or field businterfaces (Ethernet/IP, EtherCAT, Profinet,

Devicenet, CANopen, Profibus, etc)

Absolute encoders are used in applications were position information is necessary

Code disc for absoluteencoders

LEDLens

Scanning mask

Code disc Photo-

Elements

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Encoder Selection Process

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Electrical Interface

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Encoder

Rotary Encoder

Incremental Absolute

Types of Encoders

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Incremental EncodersOutput Channels

: Incremental encoders - produce electrical pulses or increments (usually as a

square wave) with linear or rotary motion of the encoder

: Resolution- The number of pulses or increments per channel, per

revolution. Also known as Pulses Per Revolution, or PPR

: Quadrature:- The standard convention is to output two square wave

channels along with their complements

- Channels A and B are offset by ¼ of a cycle – using all four channels with this output, we can interpolate 4 positions within one pulse cycle. This is known as “quadrature”

- The 1/4th offset also allows us to see which direction the encoder is turning based on what channel is leading. If channel A goes high first followed by channel B, we can determine the direction of rotation, and visa versa.

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Incremental EncodersElectrical Signals

: Output Voltages - Standard output voltages are HTL, TTL or Open Collector.

These refer to the amplitude of the square waves

: HTL (High Threshold Logic)- Also known as “push pull”

- The output voltage will be the same as the supplyvoltage (e.g if the supply on the encoder is 24V, the output signal will also be ~24V)

: TTL (Transistor Transistor Logic)- Also known as a “differential line driver” or “RS422”

- The output voltage will always be 5V regardless ofthe supply voltage on the encoder

: Open Collector- Instead of outputting a signal of a specific voltage or

current, the output signal is applied to the base of an internal NPN transistor whose collector is externalized

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Incremental Encoder – Electronic Interface Summary

•Standard Supply voltages are 5VDC, 10-32 VDC, and 8-24VDC•Standard outputs are TTL, HTL and Open collector

Incremental

Electronic Interface

TTL / RS 422

Supply = 5VTTL / RS 422

Supply = 10 ... 32V

HTL / Push Pull

Supply = 10 ... 32V

Open Collector

Supply = 8-24 V

Incremental EncodersInterface Summary

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Encoder

Rotary Encoder

Incremental Absolute

MultiturnSingleturn

Absolute EncodersSingleturn vs Multiturn Absolute Encoders

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Singleturn and Multiturn Absolute

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Absolute

Electronic Interface

SSIParallel BUS

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Absolute Encoder Interfaces

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: Parallel Output- First form of communication for absolute encoders

: Connection- Point-to-point communication where each output wire

represents a different data bit

: Benefits- Direct output to digital inputs- Fast (60us typically)

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: Drawbacks- Complex cabling due to separate bit wires

- High cost

Parallel Output

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: Synchronous Serial Interface (SSI)- Very common serial interface standard for industrial applications- Developed by Stegmann in 1984 for absolute encoders – now in many products

: Connection- Point-to-point connection from a master (PLC, microcontroller) to a slave (encoder)

: Benefits- Simple cabling, especially compared to

parallel outputs- Fast communication speeds- Low cost

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: Drawbacks- Point-to-point connection, topology restrictions

Synchronous Serial Interface (SSI)

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Network Encoders

: What do we (or the customer) mean when we say “network encoder”?

- A network is a collection of products (sensors, HMIs, processes, etc) that are connected to a central controller or share information between parts.

- Also known as Field Bus

- Example: an Internet VPN (virtualprivate network):

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: Field Bus- Industrial network system that connects multiple products in a manufacturing plant or on a

machine

: Benefits- Products are no longer point-to-point which allow multiple products to be connected to one

controller- Generally does not require as many cables as a point to point configuration, and cables do not

need to be as long. This saves on system costs.- Typically the controller has more flexibility for configuration and information gathering

: Disadvantages- The network topologies are generally more complex- Individual components cost more than standalone products (potential system savings, however)

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Field Bus Interfaces

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SICK Absolute Encoder Fieldbus Interfaces

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ATM60 SeriesAFx60 Series

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Electrical Interface SummaryThings to know when choosing an encoder

: Incremental Encoders

- Resolution (PPR)

- Supply Voltage

- Output Voltage (HTL, TTL or Open Collector)

- Programmable Encoders:

DFS60 and DFS2x encoders let you program ALL electrical configurations except an open collector output

: Absolute Encoders

- Resolution (singleturn, multiturn)- Output type

▪ Parallel (output voltage needed)▪ SSI▪ Fieldbus

- Programmable Encoders

Programmable options for SSI encoders to program the resolution. All field bus encoders are programmable over their respective networks

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Encoder Selection Process

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Mechanical Considerations

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: Housings and Connection

- Housing Size

- Cable or Connector

: Shafts

- Solid, blind hollow, through hollow

- Sizes, shaft load

: Flange

- Face mounting flange

- Servo flange

- Square Flange

- Tethers

Mechanical Characteristics

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Encoder Selection Process

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Product Overview - Rotary Encoders

Absolute Singleturn Encoders Absolute Multiturn Encoders

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Product Overview - Linear Encoders

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Key Products in 2013Choice encoders that will solve most applications

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AFx60 SeriesWith Ethernet

DFS60 with PGT-10-SProgramming Tool

BCG Wiredrawwith Analog Output

DFS20/25Incremental Encoder

• Handheld, battery operated programming tool

• Easy menu structure for fast setup and flexibility

• Can be used for diagnostics with the display or as a cloning module

• USA sized encoders with SICK’s “F”-Technology:

• Wide set bearings for even shaft loading

• Metal code disc for high vibration and temperature

• Programmable using the PC-based tool

• Absolute single- and multi-turn encoders with EtherNet/IP, EtherCAT, and Profinet interfaces

• Device Level Ring (DLR) functionality with the EtherNet/IP version

• Superior diagnostics for temperature, speed, runtime, and many more

• Compact wiredraw encoder for applications in tight spaces

• Up to 10m of measuring length

• Analog output scalable directly on the encoder for fast commissioning

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Handling

Wood industry

Automotive Ports & Cranes

Packaging

Machine Tooling

Print & Paper

… And many more

Fields of applications

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Application Examples

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OVERHEAD CRANE– AFM60 EtherNet/IP used to track position of crane

CONVEYORS – DKV60 used to track speed of conveyor

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Application Examples

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WIND TURBINE – Absolute encoder AFM60 for gandala and blade angle tracking

BOTTLING – Absolute encoder AFS60 to track position of fillers

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Application Examples

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STADIUM ROOF – Position with KH53 Linear Encoder

LIFT APPLICATIONS – Height and Width positioning using BGC Wiredraw Encoders

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Additional Resources

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Demonstration Videos & Application Animations

SICK University TourMarch – May 2013

Product Training Demo Cases

Tech Tuesdays Check www.sickusa.com for schedule

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Marketing Tools

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Encoder Selection Guide

Application BookEncoder Catalog*Update in 2013

: Thank you for your attention.