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Encoders – Basic Training. Mandee Liberty & Vikram Phadke National Encoder Product Specialists. Typical Industrial System. Input. Output. Operation (Application). Controller. Feedback. Sensor. 2. Encoders within a Control System. Feedback. Sensor. Encoder. Encoder Definitions.
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Encoders – Basic Training Mandee Liberty & Vikram Phadke National Encoder Product Specialists
Typical Industrial System Input Output Operation (Application) Controller Feedback Sensor 2
Encoders within a Control System Feedback Sensor
Encoder Encoder Definitions What is an encoder? • An encoder is a device which converts a mechanical information of a shaft or position into an electrical signal
Receiver / Sensor Code disc Lens Transmitter / LED Shaft Encoder Definitions How is this accomplished? • As the code disc rotates, it shutters light from the LED and is received and transmitted as square\sine waveforms
Type (Rotary, Linear, Incremental, Absolute) Encoder Selection Process
Types of Encoders Encoder Rotary Encoder Linear Encoder
Types of Encoders Encoder Linear Encoder Wire Draw Linear with Scale
Types of Encoders Encoder Rotary Encoder Linear Encoder Wire Draw Linear with Scale Incremental Absolute Incremental Absolute
Incremental Encoders 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 positionafter apower cycle • Incremental encoders are typically used forspeed or applications that do not require absolute position
LED Lens Scanning mask Code disc Photo- Elements Absolute Encoders Absolute • Provides a unique valuefor 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
Type (Rotary, Linear, Incremental, Absolute) Encoder Selection Process Electrical Interface
Types of Encoders Encoder Rotary Encoder Incremental Absolute
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. : Name (Date)
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 5Vregardless 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 isexternalized : Name (Date)
Incremental EncodersInterface Summary 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 HTL / Push Pull Supply = 10 ... 32V Open Collector Supply = 8-24 V TTL / RS 422 Supply = 5V TTL / RS 422 Supply = 10 ... 32V
Absolute EncodersSingleturn vs Multiturn Absolute Encoders Encoder Rotary Encoder Incremental Absolute Singleturn Multiturn
Absolute Encoder Interfaces Absolute Electronic Interface Parallel SSI BUS
Parallel Output • Parallel Output • First form of communication for absolute encoders • Connection • Point-to-point communication where each output wirerepresents a different data bit • Benefits • Direct output to digital inputs • Fast (60us typically) • Drawbacks • Complex cabling due to separate bit wires • High cost : Name (Date)
Synchronous Serial Interface (SSI) • 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 • Drawbacks • Point-to-point connection, topology restrictions : Name (Date)
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): : Name (Date)
Field Bus Interfaces • 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) : Name (Date)
SICK Absolute Encoder Fieldbus Interfaces AFx60 Series ATM60 Series NEW! : Name (Date)
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 : Name (Date)
Type (Rotary, Linear, Incremental, Absolute) Encoder Selection Process Electrical Interface Mechanical Considerations
Mechanical Characteristics • 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
Type (Rotary, Linear, Incremental, Absolute) Encoder Selection Process Electrical Interface Mechanical Considerations
Product Overview - Rotary Encoders Absolute Singleturn Encoders Absolute Multiturn Encoders
Key Products in 2013Choice encoders that will solve most applications DFS60 with PGT-10-SProgramming Tool BCG Wiredrawwith Analog Output DFS20/25Incremental Encoder AFx60 SeriesWith Ethernet • 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
Automotive Handling Wood industry Ports & Cranes Packaging Machine Tooling Print & Paper Fields of applications … And many more
Application Examples OVERHEAD CRANE– AFM60 EtherNet/IP used to track position of crane CONVEYORS – DKV60 used to track speed of conveyor
Application Examples WIND TURBINE – Absolute encoder AFM60 for gandala and blade angle tracking BOTTLING – Absolute encoder AFS60 to track position of fillers
Application Examples STADIUM ROOF – Position with KH53 Linear Encoder LIFT APPLICATIONS – Height and Width positioning using BGC Wiredraw Encoders
Additional Resources SICK University TourMarch – May 2013 Tech Tuesdays Check www.sickusa.com for schedule Product Training Demo Cases Demonstration Videos & Application Animations
Marketing Tools Encoder Catalog *Update in 2013 Encoder Selection Guide Application Book