Section 3 - Slide 1/19 P&T - GPS - Formation PhW - CANopen_lev1_en - 01/2004 History CANopen and the ISO model Physical layer Link layer Application layer Profiles Strengths - Weaknesses CANopen

Section 3 - Slide 2/19 P&T - GPS - Formation PhW - CANopen_lev1_en - 01/ : Creation of CAN as an initiative by the German equipment manufacturer BOSCH to meet a requirement in the automotive industry. CAN only defines one part of layers 1 and 2 of the ISO model : The prices of drivers and micro-controllers featuring CAN become very attractive as they are used in high volume in the automotive industry. 1991: CIA = CAN in Automation is born: to promote industrial applications. History

Section 3 - Slide 3/19 P&T - GPS - Formation PhW - CANopen_lev1_en - 01/ : CiA publishes the DS-301 communication profile: CANopen 2001: CiA publishes DS-304 which can be used to integrate level 4 safety components on a standard CANopen bus (CANsafe). 1993: CAL = CAN Application Layer specifications published by CiA describing transmission mechanisms but not when and how to use them. History

Section 3 - Slide 4/19 P&T - GPS - Formation PhW - CANopen_lev1_en - 01/2004 CANopen and the ISO model CiA DS-301 = Communication profile EMPTY CAN 2.0 A and B + ISO CAN 2.0 A and B = ISO and 2 ISO 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 CANopen is based on CAL

Section 3 - Slide 5/19 P&T - GPS - Formation PhW - CANopen_lev1_en - 01/2004 Medium:Shielded twisted pair 2 or 4-wire (if power supply) Topology: Bus type With short tap links and 120 ohm line termination resistor Maximum distance:1000 m Speed:9 possible speeds from 1 Mbps to 10 Kbps Depends on bus length and cable type: 25 m at 1 Mbps, 1000 m at 10Kbps Max. no. of devices: master and 127 slaves Physical layer

Section 3 - Slide 6/19 P&T - GPS - Formation PhW - CANopen_lev1_en - 01/2004 CiA recommendation DR includes a list of suitable connectors divided into 3 categories with a description of their pin configuration. Male, product side 9-pin SUB D DIN RJ45 Open style 5-pin Micro Style = M12 ANSI/B93.55M-1981 Connectors

Section 3 - Slide 7/19 P&T - GPS - Formation PhW - CANopen_lev1_en - 01/2004 Example architecture Premium ATV58 TEGO POWER FTB1CN TEGO POWER Line termination resistor Line termination resistor (120  ) Line termination resistor

Section 3 - Slide 8/19 P&T - GPS - Formation PhW - CANopen_lev1_en - 01/2004 Medium access method: CSMA/CA Every device may send data as soon as the bus is free. The principle of dominant and recessive bits enables non-destructive bit-by-bit arbitration in the event of a collision. The priority of a message is indicated by the value of the identifier. The identifier with the lowest value has priority. On CANopen the identifier value depends on the address of the product and which type of message is transmitted (process data, service data, synchronization message…) Link layer

Section 3 - Slide 9/19 P&T - GPS - Formation PhW - CANopen_lev1_en - 01/2004 Structure of the CAN frame CRC sequence Start of frame (SOF) Identifier RTR Remote Transmission Request bit Data field CRC delimit. ACK slot to ACK delimit. End of frame (EOF) Arbitration field Control field: compatibility and length Frame size without bit stuffing: 47 to 111 bits

Section 3 - Slide 10/19 P&T - GPS - Formation PhW - CANopen_lev1_en - 01/2004 Dominant and recessive bits SOFRTR Control field Identifier Station 2 loses arbitration Station 1 loses arbitration Station 1 Station 2 Station 3 D R S1 S2S3

Section 3 - Slide 11/19 P&T - GPS - Formation PhW - CANopen_lev1_en - 01/2004 Communication model: Producer/Consumer An identifier coded on 11 bits and located at the start of the message informs the receivers about the type of data contained in each message. Each receiver decides whether or not to accept the data. This concept permits multiple communication models : Transmission on change of state, cyclic, SYNC signal, on Remote frame (Master/Slave). Link layer

Section 3 - Slide 12/19 P&T - GPS - Formation PhW - CANopen_lev1_en - 01/2004 Link layer Max. size of useful data: 8 bytes per frame Transmission security: One of the best local industrial networks Numerous signalling and error detection devices ensure high transmission security.

Section 3 - Slide 13/19 P&T - GPS - Formation PhW - CANopen_lev1_en - 01/ types of standardized service: 1. Network administration: Parameter settings, start-up, monitoring (master-slaves) 2. Transmission of low-volume process data (<= 8 bytes) in real time: PDO = Process Data Object (producer-consumer) PDOs can be transmitted on changes of state, cyclically, on receipt of the SYNC message or at the request of the master Transmission of high-volume parameter data (> 8 bytes) by segmentation without time restrictions: SDO = Service Data Object (client-server) 4. Predefined messages for managing synchronization (SYNC), time-based references, fatal errors: SFO = Special Function Object Application layer

Section 3 - Slide 14/19 P&T - GPS - Formation PhW - CANopen_lev1_en - 01/2004 Application layer 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

Section 3 - Slide 15/19 P&T - GPS - Formation PhW - CANopen_lev1_en - 01/2004 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

Section 3 - Slide 16/19 P&T - GPS - Formation PhW - CANopen_lev1_en - 01/2004 Structure of the “Object Dictionary”

Section 3 - Slide 17/19 P&T - GPS - Formation PhW - CANopen_lev1_en - 01/2004 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 Function CodeNode ID

Section 3 - Slide 18/19 P&T - GPS - Formation PhW - CANopen_lev1_en - 01/2004 Allocation of default identifiers 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.

Section 3 - Slide 19/19 P&T - GPS - Formation PhW - CANopen_lev1_en - 01/2004 Strengths - Weaknesses Strengths Cost of connection point Wide selection of drivers Interference resistant Open protocol Flexibility Weaknesses Bus length at 1 Mbps = 25 m Level of integration in PL7 Current Schneider offer Non-deterministic