Using DeviceNet Tuesday, August 25 10:15-11:15 and 11: :30 Cedar (8C) Rodney Cummings Engineering Group Manager Chris LeBlanc Industrial Comm Product Manager

Presentation Overview DeviceNet background Technical overview Open DeviceNet Vendors Association National Instruments DeviceNet products Future plans for DeviceNet products Questions and answers

DeviceNet Background

DeviceNet Timeline Bosch defines CAN for automotive applications Allen-Bradley uses CAN as basis for DeviceNet, for industrial applications DeviceNet transferred from AB to ODVA Semiconductor manufacturing standardizes on Dnet, ODVA > 250 members

Advantages of Device Networks Reduced wiring Controller

Advantages (cont.) Improved device diagnostics Transition from centralized control to distributed control Consistent behavior for standard devices Modular, object-oriented design

DeviceNet Markets Manufacturing automation –Assembly line control –PLC/PC to sensors/actuators –Automotive, bottling, packaging, … Semiconductor manufacturing equipment –Future wafer manuf. systems –Equipment controller to sensors/actuators Process Automation, “Prime Mover”,...

Traditional PLC-based Control PC used for HMI/SCADA Large PLC uses scanner interface as a Dnet master Dnet slaves Proprietary PLC protocol (RS-232 or Ethernet) DeviceNet

PC-Based Control PC communicates as a Dnet master “micro” PLC other Dnet slaves DeviceNet

Technical Overview

Physical characteristics Object modeling Explicit message connections I/O connections Assembly objects Device profiles

Physical Characteristics 125, 250, or 500 Kbaud Up to 64 devices per network Differential signaling Power available on bus Cable/connectors: –Screw terminal: versatile –Mini: used for trunk lines –Micro: used for drop lines screw terminal mini / micro

Object Modeling Class – models common behavior/features Instance – the real implementation Attributes – externally visible data values Services – used to perform tasks Behavior –: what the object does

Object Modeling (cont.)

Explicit Message Connections Used to execute a Service on a device Normally used for configuration Request/response scheme Request includes service ID, class ID, instance ID Common services include Get Attribute, Set Attribute, Reset Example – set range/units attrs. for AI point

I/O Connections Used for ‘run-time’ communication Multiple attributes in each I/O message Master/slave scheme Slave can only comm. with its master Types of master/slave I/O –Polled – traditional request/response –Strobed – simultaneous sensor inputs –Change-of-state – input msg when data changes –Cyclic – periodic input msg from slave

Assembly Objects Instance attributes Instance attributes Instance attributes Output msg from master Input msg sent to master

Assembly Object Example

Device Profiles Interoperability for devices of same type All devices in a profile must provide the same: –Behavior –Objects –I/O assemblies –Configurable parameters Vendor-specific extensions are allowed

Device Profile Examples position sensor position controller photoelectric sensor AC drive overload relay

Open DeviceNet Vendors Association

Open DeviceNet Vendors Assoc Formed in 1994 to open DeviceNet to multiple vendors Handles marketing and technical activities Over 250 member companies and growing Special interest groups (SIGs) propose additions to the specification Within each SIG – one vendor, one vote

ODVA Special Interest Groups System Architecture SIG Conformance SIG Semiconductor SIG Smart I/O SIG Physical Layer SIG SIGs for existing device profiles

National Instruments DeviceNet Products

Interface cards for ISA, PCMCIA, PCI, PXI ™ NI-DNET ™ software for Windows 95, Windows 98, Windows NT Libraries and examples for –LabVIEW ™ (BridgeVIEW ™ ) –LabWindows ™ /CVI –Microsoft Visual C/C++, Borland C/C++ –Visual Basic

National Instruments DeviceNet Products (cont.) Master support: –Explicit messaging –Polled I/O –Strobed I/O –COS/cyclic I/O Slave support – PC can perform I/O as slave Lower cost and higher performance than leading DeviceNet competitors Next 2 slides – LabVIEW example

Future Plans for DeviceNet Products

Future Plans – IA Integration OPC server – seamless integration into BridgeVIEW, Lookout, or any other HMI/SCADA F OUNDATION Fieldbus – integrated configuration utility

Future Plans – Instrument Drivers Software to facilitate access to devices Instrument driver for each device profile, not vendor DeviceNet fits well into instrument driver tools of LabWindows/CVI 5 First release includes: –Position controller –Mass flow controller –Generic device (template)

Questions and Answers