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Section 2 - Slide 1/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 CANopen CANopen Section 1: History Section 2: Physical layer Section 3: Link.

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Presentation on theme: "Section 2 - Slide 1/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 CANopen CANopen Section 1: History Section 2: Physical layer Section 3: Link."— Presentation transcript:

1 Section 2 - Slide 1/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 CANopen CANopen Section 1: History Section 2: Physical layer Section 3: Link layer Section 4: Application layer Section 4: Main characteristics resume

2 Section 2 - Slide 2/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 CANopen Section 1: History

3 Section 2 - Slide 3/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Section 1 : History History 1980-1983: CAN developed on the initiative of the German equipment manufacturer BOSCH in response to a need in the automotive industry. CAN defines only part of layers 1 and 2 of the ISO model. 1983-1987: Price of drivers and micro-controllers with integral CAN very attractive because of the high volume used by the automotive industry 1991: Launch of CiA = CAN in Automation: http://www.can-cia.de/ to promote industrial applicationshttp://www.can-cia.de/

4 Section 2 - Slide 4/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Section 1 : History History 1995: Publication by CiA of the DS-301 communication profile: CANopen 2001: Publication by CiA of DS-304, enabling level 4 safety components to be integrated onto a standard CANopen bus (CANsafe). 1993: Publication by CiA of CAL = CAN Application Layer specifications describing transmission mechanisms without defining when and how to use them.

5 Section 2 - Slide 5/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 CANopen was built chronologically on the basis of several specifications: CAN 2.0 A and B (originating from Robert BOSCH) Defines precisely the link layer and part of the physical layer CAL = CAN Application Layer (CiA): Provides tools for developing an application using CAN without instructions for use + further details on the physical layer CANopen (CiA): Defines which CAL tools to use and how. Ensures interoperability of products by profile descriptions. Reference specifications Section 1 : History

6 Section 2 - Slide 6/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Section 1 : History CiA DS-301 = Communication profile EMPTY CAN 2.0 A and B + ISO 11898 CAN 2.0 A and B = ISO 11898 ISO 11898 + DS-102 Device Profile CiA DSP-401 I/O modules Device Profile CiA DSP-402 Drives Device Profile CiA DSP-404 Measuring devices Device Profile CiA DSP-4xx CAL= CAN Application Layer APPLICATION PRESENTATION SESSION TRANSPORT NETWORK LINK = LLC + MAC PHYSICAL 7 6 5 4 3 2 1 CANopen and the ISO model CAN specifications

7 Section 2 - Slide 7/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 CANopen CANopen Part 1: Network characteristics Part 2: Recommended connections Section 2: Physical layer

8 Section 2 - Slide 8/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 CiA DS-301 = Communication profile EMPTY CAN 2.0 A and B + ISO 11898 ISO 11898 + DS-102 + DRP-301-1 Device Profile CiA DSP-401 I/O modules Device Profile CiA DSP-402 Drives Device Profile CiA DSP-404 Measuring devices Device Profile CiA DSP-4xx CAL= CAN Application Layer APPLICATION PRESENTATION SESSION TRANSPORT NETWORK LINK = LLC + MAC PHYSICAL 7 6 5 4 3 2 1 Section 2: Physical layer - Part 1: Network characteristics CANopen physical layer

9 Section 2 - Slide 9/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Twisted differential pair: 1 pair if CAN-H/CAN-L 2 pairs if CAN-H/CAN-L + p. supply Characteristic line impedance:120 ohms nominal Line terminators:120 ohms at each end Wire resistance: 70 milli-ohms/metre nominal Propogation time:5 ns/metre nominal Topology:Bus type with the shortest possible tap links Description of the network Section 2: Physical layer - Part 1: Network characteristics

10 Section 2 - Slide 10/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Data rate - bus length - cable cross-section for 32 slaves maximum Section 2: Physical layer - Part 1: Network characteristics

11 Section 2 - Slide 11/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Data rate - bus length - cable cross-section for 100 slaves maximum Section 2: Physical layer - Part 1: Network characteristics

12 Section 2 - Slide 12/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 In its recommendation DR-303-1, the CiA provides a list of suitable connectors classified into 3 categories. General use 9-pin SUB D connector DIN 41652, multi-pole connector (ribbon cable to 9-pin SUB-D), RJ10 and RJ45 Industrial use 5-pin Mini Style, 5-pin Micro Style, Open Style Special use 7-pin round connector, 8-pin round connector, 9-pin round connector, 12-pin round connector, Hand Brid Harting. Recommended connections Section 2: Physical layer - Part 2: Recommended connections

13 Section 2 - Slide 13/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Pin Signal Description: 1:Reserved 2:CAN_L = CAN_L bus line dominant low 3:CAN_GND = CAN Ground 4:Reserved 5:(CAN_SHLD) Optional CAN Shield 6:(GND) Optional Ground 7:CAN_H = CAN_H bus line dominant high 8:Reserved 9:(CAN_V+) Optional CAN external positive supply 9-pin SUB D connector DIN 41652 Section 2: Physical layer - Part 2: Recommended connections Male product end

14 Section 2 - Slide 14/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 RJ45 connector Section 2: Physical layer - Part 2: Recommended connections Pin Signal Description 1:CAN_H = CAN_H bus line (dominant high) 2:CAN_L = CAN_L bus line (dominant low) 3:CAN_GND = Ground/0 V/V- 4: Reserved 5:Reserved 6:(CAN_SHLD) = Optional CAN Shield 7:CAN_GND = Ground/0 V/V- 8(CAN_V+) = Optional CAN external positive supply

15 Section 2 - Slide 15/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Pin Signal Description: 1: (CAN_SHLD) = Optional CAN Shield 2:(CAN_V+) = Optional CAN external positive supply 3:CAN_GND = Ground/0V/V- 4:CAN_H = CAN_H bus line (dominant high) 5:CAN_L = CAN_L bus line (dominant low) 5-pin Mini Style connector: ANSI/B93.55M-1981 Section 2: Physical layer - Part 2: Recommended connections Male product end

16 Section 2 - Slide 16/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Pin Signal Description: 1:CAN_GND = Ground/0 V/V- 2:CAN_L = CAN_L bus line (dominant low) 3:(CAN_SHLD) = Optional CAN Shield 4:CAN_H = CAN_H bus line (dominant high) 5:(CAN_V+) = Optional CAN external positive supply Open Style connector Section 2: Physical layer - Part 2: Recommended connections Male product end

17 Section 2 - Slide 17/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Recommended suppliers Section 2: Physical layer - Part 2: Recommended connections Cables - U.I.LAPP GmbH Schultze-Delitsch-Str. 25 D-70565 Stuttgart Germany http://www.lappcable.com Connectors - ERNI Elektroapparate GmbH Seestrasse 9 D-73099 Adelberg Germany - ERNI Connectique S.a.r.l, France 27 bis, avenue des Sources/CP 638 F-69258 LYON Cedex 09, http://connect.erni.com/ http://connect.erni.com/

18 Section 2 - Slide 18/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 CANopen CANopen Section 3: Link layer

19 Section 2 - Slide 19/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 The CAN V2.0 specification consists of 2 parts: CAN 2.0.A and CAN 2.0.B. CAN 2.0.A corresponds to the standard frame format with an identifier coded on 11 bits. It is used by CANopen and most of the application layers. CAN 2.0.B corresponds to the extended frame format with an identifier coded on 29 bits. It is very rarely used. CAN 2.0.A and CAN 2.0.B Section 3: Link layer

20 Section 2 - Slide 20/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Section 3: Link layer CRC sequence Start of frame (SOF) Identifier RTR Remote Transmission Request bit Data field CRC delimit. Structure of the CAN 2.0.A frame ACK slot 11160 to 641571111 ACK delimit. End of frame (EOF) Arbitration field Control field: compatibility and length Frame size without bit stuffing: 47 to 111 bits

21 Section 2 - Slide 21/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Section 3: Link layer Dominant and recessive bits 109876543210 SOFRTR Control field Identifier Station 1 Station 2 Station 3 D R S1 S2S3 Station 2 loses arbitration Station 1 loses arbitration Bus

22 Section 2 - Slide 22/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Each node must always contain two counters: TEC Transmit Error Counter and REC Receive Error Counter. These counters are incremented and decremented using a sophisticated weighting mechanism etched in the silicon. Depending on the value of these counters, the node will be in one of the following 3 states: Active errors Passive errors Bus OFF (sending driver disconnected from the bus). Error counters Section 3: Link layer

23 Section 2 - Slide 23/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Counter value/node status Section 3: Link layer Active errors Passive errors Bus OFF Reset and configuration REC > 127 or TEC > 127 REC < 128 and TEC < 128 TEC > 255 128 occurrences of 11 consecutive recessive bits (end of frames without errors)

24 Section 2 - Slide 24/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Data Frame: these frames transport data from a producer to consumers without any guarantee that it will be processed. Remote Frame: these request frames are sent by a client to a server to request transmission of a data frame (the identifier will have the same value as that of the request). Error Frame: these frames are transmitted when a station detects the presence of errors on the bus. Overload Frame: these frames are sent to ask for an additional time lapse between successive frames (data or request). The 4 types of CAN frame Section 3: Link layer

25 Section 2 - Slide 25/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Section 3: Link layer SOFIDENTRTRCTRDATACRC ACKEOF 1D CAN V2.0 A Data Frame 0 to 64X 1X+1R5X+1R6X11X 1D 7R SOFIDENTRTRCTRDATACRC ACKEOF 1D CAN V2.0 A Remote Frame 0 to 64X 1X+1R5X+1R6X11X7R 1R Data frame Request frame Interframe 3R Interframe 3R If a request frame is repeated, the response to this request takes priority.

26 Section 2 - Slide 26/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Section 3: Link layer ERROR FLAGERROR DELIMITER Error Frame ACTIVE ERROR FLAG: 6D 8R Frame being broadcast Error detected PASSIVE ERROR FLAG: 6R OVERLOAD FLAGOVERLOAD DELIMITER Overload Frame 6D 8R Previous frame EOF or ERROR DELIMITER

27 Section 2 - Slide 27/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 At bit level: when 5 identical bits are transmitted, an additional "stuffing" bit with the opposite value is introduced intentionally. This bit is tested and eliminated by the receiver. At frame structure level, the delimiters CRC Delimiter, ACK Delimiter, End of Frame, Error Delimiter, Overload Delimiter are integrated to enable the structure to be checked. At content validity level: a CRC sequence enables receivers to check the consistency of the data received. ACK slot: this window enables the sender to know that his message has been received correctly by at least one station (dominant bit). Protection mechanisms Section 3: Link layer

28 Section 2 - Slide 28/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 CANopen CANopen Part 1: CANopen basic concepts Part 2: CANopen objects and services Section 4: Application layer

29 Section 2 - Slide 29/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 CiA DS-301 = Communication profile EMPTY CAN 2.0 A and B + ISO 11898 CAN 2.0 A and B = ISO 11898-1 and 2 ISO 11898 + DS-102 Device Profile CiA DSP-401 I/O modules Device Profile CiA DSP-402 Drives Device Profile CiA DSP-404 Measuring devices Device Profile CiA DSP-4xx CAL= CAN Application Layer APPLICATION PRESENTATION SESSION TRANSPORT NETWORK LINK = LLC + MAC PHYSICAL 7 6 5 4 3 2 1 Section 4: Application layer - Part 1: CANopen basic concepts CANopen is based on CAL

30 Section 2 - Slide 30/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Section 4: Application layer - Part 1: CANopen basic concepts CANopen defines: how data is transmitted: DS-301 communication profile common to all products Amongst other things this defines the allocation of COB-ID identifiers for each type of message. what data is transmitted: DS-4xx product profiles specific to each product family (discrete I/O, analogue I/O, variable speed drives, encoders, etc.) These functions are described by means of a Device Object Dictionary (OD). Application layer

31 Section 2 - Slide 31/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Section 4: Application layer - Part 1: CANopen basic concepts The object dictionary OD is a sequenced group of objects that can be accessed by means of: a 16-bit index and in some cases an 8-bit sub-index It describes all the functions of the product. This description takes the form of an EDS file (Electronic Data Sheet) in ASCII format. This has a strict syntax and can be used by the bus configurators (Sycon etc.) Object Dictionary = OD

32 Section 2 - Slide 32/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Section 4: Application layer - Part 1: CANopen basic concepts Structure of the “Object Dictionary”

33 Section 2 - Slide 33/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Section 4: Application layer - Part 1: CANopen basic concepts The DS-301 communication profile: Describes the general structure of the OD and the objects located in the communication profile area: index 1000 to 1FFF. It applies to all CANopen products. DS-4xx equipment profiles: Describe associated objects for the various types of product (discrete I/O modules, analogue I/O, variable speed drives, measuring instruments). Standardised objects: index 6000 to 9FFF Specific objects: index 2000 to 5FFF Some objects are mandatory, others are optional. They can be accessed in read-only mode or in read/write mode. CANopen profiles

34 Section 2 - Slide 34/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Section 4: Application layer - Part 1: CANopen basic concepts CANopen ATV58 EDS file extract [FileInfo] FileName=A58_F.eds FileVersion=1 FileRevision=2 Description=Carte Option ATV58 CreationTime=00:00AM CreationDate=12-05-2000 CreatedBy=Marie-Annick Menanteau, Schneider Electric [DeviceInfo] VendorName=Schneider Electric ProductName=ATV58_F ProductVersion=1 ProductRevision=1 BaudRate_10=0 BaudRate_20=0 BaudRate_50=0 BaudRate_100=0 BaudRate_125=1 BaudRate_250=1 BaudRate_500=1 BaudRate_800=0 BaudRate_1000=1 Granularity=0x8 VendorNumber=0x0200005a ProductNumber=0 SimpleBootUpMaster=0 ExtendedBootUpMaster=0 SimpleBootUpSlave=1 ExtendedBootupSlave=0…. [Comments] Lines=6 Line1=Used profile: 402 Line2=Manufacturer device name: VW3A58306 Line3=Hardware version: 1.0 Line4=Software version: 1.0 Line6= This is the EDS file for the CANopen Schneider Electric ATV58 drive module CAN Communication Adapter [MandatoryObjects] SupportedObjects=12 1=0x1000 2=0x1001 3=0x6040 4=0x6041 5=0x6042 6=0x6043 7=0x6044 8=0x6046 9=0x6048 10=0x6049 11=0x6060 12=0x6061 [1000] ParameterName=Device Type ObjectType=7 DataType=0x0007 AccessType=RO DefaultValue=0x10192 PDOMapping=0

35 Section 2 - Slide 35/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Section 4: Application layer - Part 1: CANopen basic concepts CANopen communication profile DS-301 The CANopen communication profile defines 4 standardised functions: 1. Network administration: starting the bus, assigning identifiers, parameter setting and NMT (Network ManagemenT) monitoring (master-slave model) 2. High-speed transmission of process data (<= 8 bytes): PDO = Process Data Object (producer-consumer model) 3. - Transmission of parameter setting data (with segmentation can be > 8 bytes) (not time-critical): SDO = Service Data Object (client-server model) 4. Predefined messages for managing synchronisation, time references, fatal errors: SFO = Special Function Object

36 Section 2 - Slide 36/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Section 4: Application layer - Part 2: CANopen objects and services Transitions performed by the NMT master : Types of communication objects authorised: 1: Start_Remote_Nodea. NMT 2: Stop_Remote_Nodeb. Node Guard 3: Enter_Pre-Operational_Statec. SDO 4: Reset_Noded. EMCY 5: Reset_Communicatione. PDO. 6: Node initialisation stopped Network management: NMT Status chart corresponding to “CANopen minimum boot-up”* (mandatory service) Starting the bus

37 Section 2 - Slide 37/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Section 4: Application layer - Part 2: CANopen objects and services Allocation of identifiers Identifiers can be allocated in 3 different ways: Using the default allocation: CANopen Predefined Set This default allocation is compulsory and is available in the Pre-Operational state. It reduces the network configuration phase Process data is exchanged between the bus manager and the slaves Defined only for the first 4 PDOs : PDO1 to PDO4 By the user in the configuration tool : Mandatory for PDOs superior to PDO4, or PDO linking (direct exchanges between slaves) By application Pre-Operational state: Written into the objects in accordance with the dictionary by the SDO service

38 Section 2 - Slide 38/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 With the aim of reducing the network configuration phase a compulsory system for allocating default identifiers has been defined. This allocation occurs in the "Pre operational" state just after the initialization phase. It is based on dividing the COB-ID identifier into 2 parts: Function code is used to code 2 PDOs in receive mode, 2 PDOs in transmit mode, 1 SDO, 1 EMCY object, 1 Node Guarding Identifier, 1 SYNC object, 1 Time Stamp object and 1 node guarding. Node ID corresponds to the product address coded by DIP switches, for example. Allocation of default identifiers Section 4: Application layer - Part 2: CANopen objects and services 109876543210 Function CodeNode ID

39 Section 2 - Slide 39/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Allocation of default identifiers Section 4: Application layer - Part 2: CANopen objects and services Allocation of default identifiers can be used on products which support the first 4 PDOs. (The fifth PDO overlaps the area reserved for SDO) 1024 identifiers maximum reserved for PDOs.

40 Section 2 - Slide 40/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Section 4: Application layer - Part 2: CANopen objects and services Master Slave 1 Slave 2 Slave 3 All the nodes (slaves) communicate with a central station (master) Inputs Outputs Allocation of default identifiers

41 Section 2 - Slide 41/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Section 4: Application layer - Part 2: CANopen objects and services Modification of the default identifier allocation Product X Product Y Product Z Allows data to be exchanged directly without passing through the master (PDO linking). The producer-consumer concept is used. Example: Axis control

42 Section 2 - Slide 42/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 These services are used to transmit small amounts of process data (<= 8 bytes) in real time. They enable a producer device to make a variable with a maximum size of 64 bits without overhead available to one or more consumers. This service is not confirmed PDO configuration is managed at the level of each slave There are 2 types of PDOs : Receive PDO : PDO received on slave side, output data for the master Transmit PDO : PDO sent by the slave, input data for the master Process Data Objects = PDO Section 4: Application layer - Part 2: CANopen objects and services

43 Section 2 - Slide 43/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Section 4: Application layer - Part 2: CANopen objects and services Each transmit or receive PDO is described by 2 objects in the object dictionary: The PDO Communication Parameter indicates how the PDO is transmitted or received: The COB-ID used The transmit/receive mode used For transmit PDOs, the minimum time between 2 messages (inhibit time) Receive PDO : Index 1400 to 15FF - Transmit PDO : Index 1800 to 19FF The PDO Mapping Parameter indicates what data is transmitted: The list of objects in the object dictionary OD The size of each object Receive PDO : Index 1600 to 17FF - Transmit PDO : Index 1A00 to 1BFF PDOs Description of PDOs

44 Section 2 - Slide 44/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 TxPDO communication parameter objects Section 4: Application layer - Part 2: CANopen objects and services Transmit PDO: Index 0x1800 to 0x19FF

45 Section 2 - Slide 45/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 TxPDO mapping parameter objects Section 4: Application layer - Part 2: CANopen objects and services Transmit PDO: Index 0x1A00 to 0x1BFF

46 Section 2 - Slide 46/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 RxPDO communication parameter objects Section 4: Application layer - Part 2: CANopen objects and services Receive PDO: Index 0x1400 to 0x15FF

47 Section 2 - Slide 47/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 RxPDO mapping parameter objects Section 4: Application layer - Part 2: CANopen objects and services Receive PDO: Index 0x1600 to 0x17FF

48 Section 2 - Slide 48/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Synchronous: by receiving a SYNC object Acyclic:- transmission is pre-triggered by a "Remote Transmission request" - transmission is pre-triggered by the occurrence of a "Specific event" object in the device profile Cyclic:- transmission is triggered periodically after each 1, 2 or up to 240 SYNC objects PDO transmission modes Section 4: Application layer - Part 2: CANopen objects and services Asynchronous: - transmission is triggered by a "Remote Transmission request" - transmission is pre-triggered by the occurrence of a "Specific event" object in the device profile

49 Section 2 - Slide 49/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 These services are used for the point to point transmission of parameter setting data which is not time critical. They enable a client device (bus manager) to access the object dictionary of a server device (stations 1 to 127) in write or read mode, by addressing it by its Index and Sub-index. The size of the data may exceed 8 bytes, in which case a data segmentation system is activated. The result of a write or read operation is confirmed by a response. An SDO exchange requires 2 COB-IDs: one for the request, the other for the response. Service Data Objects = SDO Section 4: Application layer - Part 2: CANopen objects and services

50 Section 2 - Slide 50/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 SYNC = Synchronization Object: These objects are used to synchronize the acquisition of inputs or updating of outputs (axis control for example). The "SYNC master" sends the SYNC message at a an interval (communication cycle period) fixed at the time of configuration. Special Function Objects = SFO Section 4: Application layer - Part 2: CANopen objects and services

51 Section 2 - Slide 51/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 EMCY Object: EMCY objects are triggered when an internal fault occurs in the device (current, voltage, temperature, communication, etc). Special Function Objects = SFO Section 4: Application layer - Part 2: CANopen objects and services

52 Section 2 - Slide 52/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 There are 2 mechanisms for monitoring the status of stations on the bus. Node guarding This operates on the basis of the master-slave concept (polling), allowing the bus manager to request (remote request) the status of each station at a configurable time interval. Heartbeat This operates on the basis of the producer-consumer concept. The status of the station is generated cyclically at a configurable interval. This recently-specified mechanism replaces node guarding on new products (better utilisation of the pass band). Special Function Objects = SFO Section 4: Application layer - Part 2: CANopen objects and services

53 Section 2 - Slide 53/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Node guard object: The NMT master monitors the status of slaves connected to the network by periodically sending a Node guard object remote frame to each slave. Each slave answers immediately on reception. Slaves have the option of monitoring the NMT master: Life guarding. Life Time = Guard Time x Life Time Factor If a slave receives no polling for a period equal to the Life Time, it generates a "Life guarding" event, goes into communication fault mode and sends an EMCY object. Special Function Objects = SFO Section 4: Application layer - Part 2: CANopen objects and services

54 Section 2 - Slide 54/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Section 4: Application layer - Part 2: CANopen objects and services Node guard object: The NMT master periodically monitors the status of each slave by sending a remote frame and comparing it with the values previously recorded in a table. If a difference is detected, the information is returned to the application by means of a “network event”. Special Function Objects = SFO

55 Section 2 - Slide 55/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Heartbeat: The recently-specified heartbeat function saves on pass band utilisation as compared with node guarding. The heartbeat producer transmits the heartbeat message at an interval defined in the “Heartbeat producer time” object. The heartbeat consumer verifies that it has received the heartbeat message within the time window defined in the “Heartbeat consumer time” object. Special Function Objects = SFO Section 4: Application layer - Part 2: CANopen objects and services

56 Section 2 - Slide 56/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 CANopen Section 5: Main characteristics resume

57 Section 2 - Slide 57/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Medium:Shielded twisted pair 2 or 4-wire (if power supply) Topology: Bus type With short tap links and end-of-line resistor Maximum distance:1000 m Data rate: 9 possible data rates from 10 Kbps to 1 Mbps Depends on the length of the bus and the type of cable: 1000 m for 10Kbps, 25 m for 1 Mbps Max. no. of devices: 127 1 master and 126 slaves Physical Layer Section 5 : Main characteristics resume

58 Section 2 - Slide 58/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Network access method: CSMA/CA Each device can send data as soon as the bus is free. In the event of a collision, a principle of dominant or recessive bits can arbitrate bit by bit in a non-destructive manner. The priority of a message is given by the value of the identifier called COB- ID (Communication Object Identifier) located at the beginning of the frame. The COB-ID is coded on 11 bits: values are between 0 and 2047. The COB-ID with the lowest value has the highest priority. Link layer Section 5 : Main characteristics resume

59 Section 2 - Slide 59/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Communication model : Producer/Consumer Each message contains an identifier located at the start of the message. The identifier value informs receivers as to the type of data contained in each message. Each receiver decides whether or not to consume the data according to his configuration. Max. useful data size: 8 bytes per frame Security of transmission: Among the best on industrial local area networks. Numerous signalling and error detection devices ensure excellent security of transmission. Link layer Section 5 : Main characteristics resume

60 Section 2 - Slide 60/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Application layer Section 5 : Main characteristics resume CANopen defines: how data is transmitted: DS-301 communication profile common to all products Amongst other things this defines the allocation of COB-ID identifiers for each type of message. what data is transmitted: DS-4xx product profiles specific to each product family (discrete I/O, analogue I/O, variable speed drives, encoders, etc.) These functions are described by means of a Device Object Dictionary (OD) in the form of an EDS file.

61 Section 2 - Slide 61/61 P&T - GPS - Training PhW - CANopen_lev2_en 10/2004 Application layer Section 5 : Main characteristics resume 4 types of service have been standardised: 1. Network administration: parameter setting, starting, monitoring (master- slaves) 2. High-speed transmission of process data (<= 8 bytes): PDO = Process Data Object (producer-consumer model) 3. - Transmission of parameter setting data (with segmentation can be > 8 bytes) (not time-critical): SDO = Service Data Object (client-server model) 4. Predefined messages for managing synchronisation, time references, fatal errors: SFO = Special Function Object


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