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One Controller - Any Bus Connecting Programmable Automation
Controllers ,Measurements, Sensors, Networks and PLCs
Ian BellNational Instruments
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
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
4
PAC Architecture• Ruggedness and reliability of PLC• Software capabilities of PC• Modular and diverse I/O
Softw
are
Cap
abili
ties
Ruggedness and Reliability
PLCPLCPCPC
PAC
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
6
PLCsPACs
3 Methods to Connect to Any PLC
Industrial
Communications
Basic I/O
Analogue/Digital
OPC
7
Basic I/OCheap, 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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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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ExampleAutomated 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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PLCsPACs
3 Methods to Connect to Any PLC
Industrial
Communications
Basic I/O
Analogue/Digital
OPC
12
Methods for Industrial Communications
Ethernet/SerialPlug-In Interfaces
Gateways over Ethernet, Serial
Versatility
Performance/Determinism
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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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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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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
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
17
Ethernet-based Industrial Protocols
• Modbus TCP/IP• Ethernet/IP• EtherCAT• Profinet
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Why Ethernet: ProtocolsModbus TCP/IP
Traditional Industrial Protocols
PROFInetPROFIBUS
DeviceNet EtherNet/IP
Modbus
Ethernet Physical Layer
CanOPEN EtherCAT
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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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Ethernet-based Industrial Protocols
• Modbus TCP/IP• Ethernet/IP• EtherCAT• Profinet
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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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Ethernet/IP Terminology
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Communication from NI PAC to ControlLogix and ComapctLogix PLCs
Ethernet/IP
Uses explicit messagingAvailable for download from NI Labs
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Third-Party Gateways
• Wide variety of communication buses and protocols supported
• Ethernet or serial-based• Perfect for non-PXI, PCI, and PCMCIA systems
Ethernet
PROFIBUSDeviceNetEthernetIPControlNet
Gateways over Ethernet, Serial
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ExampleAdding 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
EthernetIPModbus TCP
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PLCsNI PACs
3 Methods to Connect LabVIEW to Any PLC
Industrial
Communications
Basic I/O
Analogue/Digital
OPC
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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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OPCClient
Allen-BradleyOPC Server
SiemensOPC Server
MitsubishiOPC Server
PLCsDevice-Specific
OPC Server
Windows PC
Ethernet/IP
PROFINET
CCLink
OPC ClientOPC
Driver
OPC Client
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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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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
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
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
35
Online Resources ni.com/commni.com/pacni.com/labs
www.modbus.org – Modbus TCP/IPwww.odva.org – Ethernet/IPwww.ethercat.org – EtherCATwww.profibus.com/pn - PROFINET