One Controller - Any Bus Connecting Programmable
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Transcript One Controller - Any Bus Connecting Programmable
One Controller - Any Bus
Connecting Programmable Automation
Controllers ,Measurements, Sensors, Networks
and PLCs
Ian Bell
National Instruments
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
2
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
3
PAC Architecture
Software Capabilities
• Ruggedness and reliability of PLC
• Software capabilities of PC
• Modular and diverse I/O
PAC
PC
PLC
Ruggedness and Reliability
4
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
5
3 Methods to Connect to Any PLC
Basic I/O
Analogue/Digital
Industrial
Communications
OPC
PACs
PLCs
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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
7
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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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 highspeed 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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3 Methods to Connect to Any PLC
Basic I/O
Analogue/Digital
Industrial
Communications
OPC
PACs
PLCs
11
Methods for Industrial Communications
Plug-In
Interfaces
Gateways over
Ethernet, Serial
Ethernet/Serial
Performance/Determinism
Versatility
12
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
13
Plug-In
Interfaces
Plug-In Communication Boards
Plug-In
Interfaces
• 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)
14
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
15
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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Ethernet-based Industrial Protocols
•
•
•
•
Modbus TCP/IP
Ethernet/IP
EtherCAT
Profinet
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Why Ethernet: Protocols
Modbus
Modbus TCP/IP
DeviceNet
EtherNet/IP
CanOPEN
EtherCAT
PROFIBUS
PROFInet
Traditional Industrial
Protocols
Ethernet Physical
Layer
18
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
19
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
Explicit Messages
• TCP/IP
• Used to set parameters and initiate
implicit communication
Implicit Messages
• UDP/IP multicast
• Used to communicate I/O data
• Normally set-up for cyclical updates
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Communication from NI PAC to
ControlLogix and ComapctLogix PLCs
Ethernet/IP
Uses explicit messaging
Available for download from NI Labs
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Gateways over
Ethernet, Serial
Third-Party Gateways
• Wide variety of communication buses and
protocols supported
• Ethernet or serial-based
• Perfect for non-PXI, PCI, and PCMCIA systems
PROFIBUS
DeviceNet
EthernetIP
ControlNet
Ethernet
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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
Modbus TCP
EthernetIP
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3 Methods to Connect LabVIEW to Any PLC
Basic I/O
Analogue/Digital
Industrial
Communications
OPC
NI PACs
PLCs
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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 devicespecific protocols
Windows PC
English
English
Speaker:
Speaker:
“Hello!”
“Hello!”
English
Spanish
Translator
Spanish
Speaker
German
Translator
German
Speaker
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French
Translator
French
Speaker
OPC Client
Windows PC
PLCs
Ethernet/IP
Allen-Bradley
OPC Server
PROFINET
Siemens
OPC Server
CCLink
Mitsubishi
OPC Server
OPC
Driver
Device-Specific
OPC Server
OPC
Client
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
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ABCO Adds LabVIEW to PLC System
“The ease by which NI can speak to the
• ABS brake testing system
Allen-Bradley hardware saved me
valuable time on this delivery-critical
• PXI for high-speed encoder job.”
-Arif Bustani, electrical engineer ABCO
measurements
• Added to existing Allen-Bradley PLC
assembly line
• OPC used for communication
between PXI and Allen-Bradley PLCs
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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
34
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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