IEEE 1451'0

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IEEE 1451.0

• Standard for a Smart Transducer Interface for
  Sensors and Actuators

2
Agenda

• Smart Transducer Functional Specification
• Message Structures
• Commands
• Transducer Services API
• Module Communications API
• Questions (both for me and from me)

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Smart Transducer Functional Specification

• This Clause of the standard provides a
  description of the functions expected to be in an
  IEEE 1451 smart transducer.
• Keep in mind - 1451 defines a PnP system
• The reference model shown on the following slides
  shows the relationships between the various IEEE
  1451 standards family members. They are used to
  help define what is in each of the standards in
  the family.

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Smart Transducer Functional Specification

• Reference Model

5
Smart Transducer Functional Specification

• Protocol Stack

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Smart Transducer Functional Specification

• User Network Anything you want
• Transducer Services Interface - defined in 1451.0
  by the API (later)
• NCAP 1451.0 Services defined in 1451.0
  (Commands TEDS)
• Module Communications Interface API defined
  here
• Communications Module defined elsewhere

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Smart Transducer Functional Specification

• TIM 1451.0 Services Counterparts to NCAP
  functions (Commands, Addresses, TEDS)
• Xducer Measurement API, Signal Conditioner Data
  Conversion Function, Xducer Analog Interface, and
  Transducer up to manufacturer
• TEDS

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Smart Transducer Functional Specification

• Addressing
• 2 levels
• Physical covered elsewhere
• TransducerNumber described here
• Several classes of address
• Global Address Broadcast address
• Accepted by all TIM
• No error responses generated

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Smart Transducer Functional Specification

• Addressing
• AddressGroup Multicast, based on group
  memberships
• Requires group registration by TransducerChannels
• TIM Address not allowed in a group
• Supports Bit Mapped (lt14) can be ORed
• b10XXXXXXXXXXXXXX
• Supports Binary Mapped (lt16383)
• b11XXXXXXXXXXXXXX
• TransducerChannel number Unicast to a smart
  transducer
• Error responses expected
• TIM Address Unicast to a TIM
• Not destined for any specific transducer

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Smart Transducer Functional Specification
NCAP
TIM
Xducer
TC
TC
TC
Xducer
TC
TC
TC
Motor
TC
???
TIM
Xducer
TC
TC
TC
TC
TC
Xducer
TC
Xducer
TC
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Smart Transducer Functional Specification

• These are found in 1451.0 at this point, but
  since others are presenting them
• Common Characteristics of all TIMs and
  TransducerChannels
• Operational States
• TEDS
• Lists Required and Optional TEDS

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Smart Transducer Functional Specification

• TransducerChannel Type Descriptions
• Sensor
• Measure a physical parameter and return a digital
  representation of the parameter
• TIM collects data and controls data exchange
• Read TransducerChannel data-set segment command
  should be answered with the most recently
  recorded data.

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Smart Transducer Functional Specification

• TransducerChannel Type Descriptions
• Event Sensor
• Detects events, not magnitude
• Has binary state
• Digital events
• May include actuators to set test pattern or
  sensors to return digital value
• Analog Events
• May have actuator to set threshold or sensor to
  return digitized analog value

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Smart Transducer Functional Specification

• TransducerChannel Type Descriptions
• Event Sensor (continued)
• Event Time
• Polling vs streaming physical media is major
  factor
• TimeInstance sensor Annex L.2 L.3
• Edge-to-Report Command
• Capabilities defined in TEDS
• Status
• Data/event status bit (operational and triggered)
• Missed data or event status bit (operational but
  not triggered)
• Hardware Error status bit

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Smart Transducer Functional Specification

• TransducerChannel Type Descriptions
• Actuator
• Physical or embedded output action
• Occurs upon trigger as commanded by TIM
• Set according to a data-set
• If multiple points are given, TIM determines
  delivery period
• Set to predefined state (no data-set required)

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Smart Transducer Functional Specification

• Embedded TransducerChannels
• Contained completely within a TIM
• Main advantage is that embedded TCs are defined
  by standardized TEDS, not control commands

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Smart Transducer Functional Specification
NCAP
TIM
Xducer
Event Sensor TC
Xducer
Sensor TC
TC
TC
Motor
Actuator TC
TC
ETC
Switch
TIM
Xducer
Event Sensor TC
Xducer
Sensor TC
TC
TC
Xducer
TC
Sensor TC
ETC
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Smart Transducer Functional Specification

• TransducerChannel Groups
• Control Groups
• Define collections of TCs where one is primaryTC
  and others are supporting TCs (embedded?)
• Max 4 in a Control Group
• Vector Groups
• Define a collection of TCs that describe
  different parts (vectors) of the same physical
  data
• Components of a 3-axis accelerometer
• Must all be on same TIM
• Implies computational relationship

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Smart Transducer Functional Specification

• TransducerChannel Proxy
• Artificial construct
• Used to combine several outputs into a single
  structure
• Defined by meta-TEDS
• Mutually exclusive to TC types (all sensors or
  all actuators)
• Used for time correlation
• Block and interleave transfer methods
• Block unequal length data-sets in series
• Interleave equal length data-sets, interleaved

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Smart Transducer Functional Specification

• Operating Modes
• Sampling Modes
• Trigger-initiated immediately upon trigger
• Free-running w/o pre-triggers requires trigger,
  fills a data-set, then idles until next trigger
• Free-running w/ pre-triggers no actuators
  allowed!
• FR w/ PT w/o buffers fill pre-triggers until
  trigger, fill remaining data-set (if DS size is
  bigger than pre-trigger number) and transfer,
  then roll pre-triggers until next trigger
• Reads before the next trigger return null data
  sets

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Smart Transducer Functional Specification

• Operating Modes
• Sampling Modes
• Free-running w/ pre-triggers no actuators
  allowed!
• FR w/ PT w/ buffers rolls pre-triggers until
  trigger, fills buffers at every trigger until
  buffers are all full, buffers empty upon read
  commands.
• Continuous Sampling Mode rolls buffers
• Sensors supply oldest buffers first upon read
• Actuators apply oldest buffers first, at TC set
  rate
• End-of-data-set operations recirculate, hold

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Smart Transducer Functional Specification

• Operating Modes
• Sampling Modes
• Immediate Operation Read/Write
  TransducerChannel data-set segment command acts
  as trigger

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Smart Transducer Functional Specification

• Operating Modes
• Data Transmission Mode
• Only When Commanded Xmit only in response to a
  Read TC data-set segment command
• Streaming When Full Xmit as soon as buffer is
  full
• Actuators cant stream, they use continuous
  sample mode
• Streaming at a Fixed Interval like it says

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Smart Transducer Functional Specification

• Operating Modes
• Buffer Operation Mode
• Behavior already defined in sampling modes
• When used
• multiple buffers (data sets) used in TIM
• Data may be several triggers old
• When not used
• single buffer (data sets) used in TIM
• TIM response may have more latency

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Smart Transducer Functional Specification

• Operating Modes
• End-of-data-set operation mode
• Already touched on (continuous sampling mode)
• Only applies to actuators
• Hold apply last sample until new trigger
• Recirculate apply last data-set, in order,
  until new trigger

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Smart Transducer Functional Specification

• Operating Modes
• Streaming Mode
• Already touched on (data transmission modes)
• Defined in 2 places (not entirely sure why)
• Edge-to-Report Operating Mode rising, falling,
  both
• Actuator-Halt Mode
• Halt immediate and hold
• Halt at end of data set and hold
• Ramp to a predefined state

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Smart Transducer Functional Specification

• Synchronization methods for achieving
• Triggers
• Delayed triggers
• Synchronization signal

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Smart Transducer Functional Specification

• Status Bits

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Smart Transducer Functional Specification
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Message Structure

• Command Message Structure

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Message Structure

• Reply Message Structure
• Success/fail flag successful if zero else,
  check status bits for reason

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Message Structure

• TIM Initiated Message Structure

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Commands Standard Commands

• Standard Command Classes

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Commands Standard Commands

• Commands common to the TIM and TC

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Transducer Idle Commands
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Commands Standard Commansd

• Transducer Operating State commands

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Transducer Idle or Operating State commands
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Commands Standard Commansd

• TIM Sleep State commands

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Commands Standard Commansd

• TIM Active State commands

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Commands Standard Commansd

• TIM Any State commands

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Commands

• Manufacturer-Defined Commands
• Manufacturer must implement the appropriate
  Commands TEDS in order to inform the user of
  the presence of these commands
• User must implement any necessary software

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Transducer Services API

• IDL used to describe the APIs functions
• Interface Definition Language
• Purpose keep the definition language independent

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Transducer Services API

• Args
• Data types generic and 1451 specific
• Util
• Command encoders and decoders
• Protocol Packet Assemblers (codec)

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Transducer Services API

• Transducer Services API Classes and Interfaces

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Transducer Services API

• Tie in to last week
• UML package diagram
• Package is a group of classes
• Dependencies

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Module Communications API

• Module Communications API Classes and Interfaces

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Question!

• Design a smart sensor
• Pick a application and a
• Xducer/Actuator
• Sampling mode
• Triggering mode
• Data transmission mode
• Buffered operation mode
• End-of-data-set operation mode
• Streaming mode
• Edge-to-report operating mode
• Actuator halt mode
• Synchronization concerns
• Embedded TransducerChannels?
• Provide a BRIEF justification for each of your
  choices