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One Controller - Any Bus Connecting Programmable Automation Controllers,Measurements, Sensors, Networks and PLCs Ian Bell National Instruments
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2 Agenda Industrial Communications Overview Why Connect a PAC to Industrial Networks and PLCs? 3 Methods to Connect to Any PLC or Device Basic Analogue and Digital I/O Industrial Network Communication OPC
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3 Industrial Communications Overview Industrial communications connect industrial devices such as PLCs, sensors and actuators Common Industrial Networks DeviceNet PROFIBUS Modbus TCP Modbus Serial CANopen FOUNDATION fieldbus Interbus CC-Link LonWorks HART PROFINET Ethernet/IP
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4 PAC Architecture Ruggedness and reliability of PLC Software capabilities of PC Modular and diverse I/O Software Capabilities Ruggedness and Reliability PLC PC PAC
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5 Why Connect PACs to Industrial Networks and PLCs? High-speed analogue measurements High-resolution analogue measurements Advanced analysis (digital filtering, frequency analysis) Custom hardware performance with FPGA technology High-speed closed-loop control FPGA-based processing and analysis Custom Sensors/Measurements
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6 PLCsPACs 3 Methods to Connect to Any PLC Industrial Communications Basic I/O Analogue/Digital OPC
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7 Basic I/O Cheap, Easy, Fast and Effective Available on every platform Analog and digital I/O options PLC users can easily integrate analogue and digital I/O into their code Allows PACs to act as intelligent devices
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8 Basic I/O Advantages Fast, deterministic, little or no software overhead Considerations Doesn’t scale well Point-to-point wiring (parallel) Can’t communicate lots of data
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9 Example Automated Filling of Aerosol Cans Existing PLC system was being used to automate the filling of aerosol cans PLC did not have the capability to do high- speed analogue for pressure measurements NI CompactRIO PAC was used for high-speed pressure measurements on 8 channels (2 k per channel) CompactRIO and PLC were integrated using digital I/O
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11 PLCsPACs 3 Methods to Connect to Any PLC Industrial Communications Basic I/O Analogue/Digital OPC
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12 Methods for Industrial Communications Ethernet/Serial Plug-In Interfaces Gateways over Ethernet, Serial Versatility Performance/Determinism
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13 Plug-In Communication Boards CAN and CANopen DeviceNet FOUNDATION fieldbus Serial (RS232, RS422, RS485) Third-party PROFIBUS (Comsoft) Support for PXI, PCI, PCMCIA, and CompactRIO Plug-In Interfaces
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14 Plug-In Communication Boards Advantages Direct, deterministic communication with the processor Timing and synchronisation with other I/O (DAQ) High-level API support for LabVIEW and other programming languages Considerations Many smaller buses and protocols are not supported Many only available on PC and PXI (real-time supported) Plug-In Interfaces
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15 Example : PROFIBUS PROFIBUS master/slave for PXI and PCI More than 2 million nodes Popular in Europe and Asia Recommended: Comsoft DF PROFI II interfaces
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16 cRIO-PBMaster/Slave and cRIO-PBSlave cRIO PB Master/Slave module Supports operation as DP Master or DP Slave Ships with configuration tool configurator II for DP Master configuration Ships with GSD file to configure any DP Master system cRIO PB Slave module Supports operation as DP Slave Ships with GSD file to configure any DP Master system
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17 Ethernet-based Industrial Protocols Modbus TCP/IP Ethernet/IP EtherCAT Profinet
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18 Why Ethernet: Protocols Modbus TCP/IP Traditional Industrial Protocols PROFInetPROFIBUS DeviceNet EtherNet/IP Modbus Ethernet Physical Layer CanOPENEtherCAT
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19 Modbus TCP/IP Overview First industrial protocol on Ethernet (introduced 1999) Based on Modbus developed by Modicon in 1979 Widely adopted and open Ethernet standard Advantages Uses standard Ethernet (hardware and TCP/IP transport layer) Open and relatively simple Disadvantages Not a hard real-time protocol Does not deliver determinism
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20 Ethernet-based Industrial Protocols Modbus TCP/IP Ethernet/IP EtherCAT Profinet
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21 EtherNet/IP Overview Dominant bus for Rockwell Automation Managed by Open Device Vendors Association (ODVA) Extends DeviceNET concepts to Ethernet Advantages Uses Ethernet transport layer (TCP and UDP) Disadvantages Can overload networks with UDP messages if not correctly configured, recommend managed switches with IGMP snooping
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22 Ethernet/IP Terminology TCP/IP Used to set parameters and initiate implicit communication Explicit Messages UDP/IP multicast Used to communicate I/O data Normally set-up for cyclical updates Implicit Messages
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23 Communication from NI PAC to ControlLogix and ComapctLogix PLCs Ethernet/IP Uses explicit messaging Available for download from NI Labs
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24 EtherNet/IP VIs for LabVIEW Provides VIs for communication to “Logix” PLC Tags Directly read and write tags on Allen Bradley ControlLogix and CompactLogix PLCs Runs on LabVIEW for Windows and LabVIEW Real- Time (Pharlap and VxWorks) Explicit Messaging Good for low numbers of tags
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25 EtherNet/IP VIs for LabVIEW Advantages Simple method to communicate to Rockwell PLCs LabVIEW initiated communication (no need to change PLC code) Good for communicating low number of tags Uses TCP/IP and does not require IGMP snooping to prevent network flooding Disadvantages Not recommended for high tag counts Inefficient packing of data into Ethernet (slower communication) Increased processor burden on PLC Can only communicate to Rockwell Logix PLCs No SLC support, no third party EtherNet/IP device support
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26 Third-Party Gateways Wide variety of communication buses and protocols supported Ethernet or serial-based Perfect for non-PXI, PCI, and PCMCIA systems Ethernet PROFIBUS DeviceNet EthernetIP ControlNet Gateways over Ethernet, Serial
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27 Example Adding Vision for Food Processing Optimisation Needed NI Compact Vision System to calculate the mass/volume of the food item coming through on the conveyor belt Ethernet/IP connectivity was a requirement EthernetIP Modbus TCP
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28 PLCsNI PACs 3 Methods to Connect LabVIEW to Any PLC Industrial Communications Basic I/O Analogue/Digital OPC
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29 What Is OPC? Universal language for reading and writing data OPC Client: Read and write to OPC OPC Server: Translates between OPC and device- specific protocols English Windows PC
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30 OPC Client Allen-Bradley OPC Server Siemens OPC Server Mitsubishi OPC Server PLCs Device-Specific OPC Server Windows PC Ethernet/IP PROFINET CCLink OPC Client OPC Driver OPC Client
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31 NI OPC Servers for Third-Party PLCs OPC support for more than 100 PLCs Connects with LabVIEW DSC OPC client Evaluation version included with DSC Servers included for: Allen-Bradley AutomationDirect Cutler-Hammer GE Hilscher Modbus Omron Philips Siemens Toshiba WAGO Yaskawa Yokogawa …and more! ni.com/opc
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32 OPC Advantages Most universal Least device-dependent Ideal for HMI and SCADA applications Considerations Slower, not deterministic, single-point only Can require PC-based OPC servers Not for safety or critical communications
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33 ABCO Adds LabVIEW to PLC System ABS brake testing system PXI for high-speed encoder measurements Added to existing Allen-Bradley PLC assembly line OPC used for communication between PXI and Allen-Bradley PLCs “ The ease by which NI can speak to the Allen-Bradley hardware saved me valuable time on this delivery-critical job.” -Arif Bustani, electrical engineer ABCO “ The ease by which NI can speak to the Allen-Bradley hardware saved me valuable time on this delivery-critical job.” -Arif Bustani, electrical engineer ABCO
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34 Summary PACs add flexibility to connect to anything Use PACs to add any measurements to existing system 3 Methods to Connect PAC to Any PLC: Basic Analogue and Digital I/O Native Industrial Communications OPC
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35 Online Resources ni.com/comm ni.com/pac ni.com/labs www.modbus.org – Modbus TCP/IP www.odva.org – Ethernet/IP www.ethercat.org – EtherCAT www.profibus.com/pn - PROFINET
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