One Controller - Any Bus Connecting Programmable Automation Controllers ,Measurements, Sensors, Networks and PLCs

1
One Controller - Any Bus Connecting Programmable
Automation Controllers ,Measurements, Sensors,
Networks and PLCs

• Ian Bell
• National 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

• Common Industrial Networks
• DeviceNet
• PROFIBUS
• Modbus TCP
• Modbus Serial
• CANopen
• FOUNDATION fieldbus
• Interbus
• CC-Link
• LonWorks
• HART
• PROFINET
• Ethernet/IP

• Industrial communications connect industrial
  devices such as PLCs, sensors and actuators

4
PAC Architecture

• Ruggedness and reliability of PLC
• Software capabilities of PC
• Modular and diverse I/O

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
3 Methods to Connect to Any PLC
PLCs
PACs
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

8
Basic I/O

• Advantages
• Fast, deterministic, little or no software
  overhead
• Considerations
• Doesnt scale well
• Point-to-point wiring (parallel)
• Cant communicate lots of data

9
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

10
(No Transcript)
11
3 Methods to Connect to Any PLC
PLCs
PACs
12
Methods for Industrial Communications
Plug-In Interfaces
Gateways over Ethernet, Serial
Ethernet/Serial
13
Plug-In Communication Boards
Plug-In Interfaces

• CAN and CANopen
• DeviceNet
• FOUNDATION fieldbus
• Serial (RS232, RS422, RS485)
• Third-party PROFIBUS (Comsoft)
• Support for PXI, PCI, PCMCIA, and CompactRIO

14
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)

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

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

18
Why Ethernet Protocols

• Modbus TCP/IP

• Modbus

• EtherNet/IP

• DeviceNet

• CanOPEN

• EtherCAT

• PROFInet

• PROFIBUS

Traditional Industrial Protocols
Ethernet Physical Layer
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

20
Ethernet-based Industrial Protocols

• Modbus TCP/IP
• Ethernet/IP
• EtherCAT
• Profinet

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

22
Ethernet/IP Terminology
23
Communication from NI PAC to ControlLogix and
ComapctLogix PLCs

• Uses explicit messaging
• Available for download from NI Labs

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

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

26
Third-Party Gateways
Gateways over Ethernet, Serial

• Wide variety of communication buses and protocols
  supported
• Ethernet or serial-based
• Perfect for non-PXI, PCI, and PCMCIA systems

• PROFIBUS

• DeviceNet

• EthernetIP

Ethernet

• ControlNet

27
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

EthernetIP
Modbus TCP
28
3 Methods to Connect LabVIEW to Any PLC
PLCs
NI PACs
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
30
OPC Client
Windows PC
Allen-Bradley OPC Server
Ethernet/IP
OPC Client
Siemens OPC Server
PROFINET
Mitsubishi OPC Server
CCLink
Device-Specific OPC Server
OPC Driver
PLCs
OPC Client
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

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

33
ABCO Adds LabVIEW to PLC System
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

• 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

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/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