LabView Users Group Meeting June 20 th, 2006 Process Control Using Compact Field Point/Labview Real-time Michael Tockstein Microelectronics Technology

LabView Users Group Meeting June 20th, 2006

Process Control Using Compact Field Point/Labview Real-time

Michael TocksteinMicroelectronics Technology Department

Electronics Photonics LaboratoryJune 20th, 2006



Outline

• Furnace Bank Control Application Overview• Requirements of our System• Compact Fieldpoint (cFP) Overview• Connecting to cFP• Labview Real-Time code structure• Remote Panels• Shared Variables• Things to Remember about Real-Time Software



Our Control Project

Gas Flow

• Wafer Processing

1 2 3



Furnace Bank


Requirements• Adaptable to Existing System• Single cFP Control Unit Covers:

– Process Sequence Controller– Gas Flow Controllers– Boat Loaders– Four Three-Zone Furnace Tubes

• Programmable for new Process• Graphical User Interface• Remote Access from Office• Technician Friendly



What is Real-Time?

• Independently Run Controllers

• Real-Time = Real Reliable


Why cFP/LV Real-Time For Our System?

• Eliminates need for separate controllers for each aspect of the process (i.e. gas flow, temp control, etc…)

• Very customizable through both hardware and software

• Best interface for our “individual” channels• Very reliable since VI runs independently

from PC• Network Ready


Compact FieldPoint Assembly

• Includes:– CPU and Process Control Module– Backplane– Digital and Analog I/O Modules– Connector Blocks



cFP Backplane

• 4 or 8 channel backplanes available

• I/O modules receive power directly from backplane

• NI data bus protocol



cFP Control Module

• Labview Real-Time code runs in on-board controller, not your PC

• Ethernet port• Serial port• 11-30 VDC input. (20W power

supply recommended) • Provides power to backplane• “cFP-2000”



Discrete Output Module

• 16 Channels, 2A sinking per channel

• Used for control of gas flow

• “cFP-DO-403”



Pulse Width Modulator (PWM) Module

• 8 channels of PWM

• Used for control of Watlow 100A Solid State Relay Firing

• Pulse period parameters set through “Measurement and Automation Explorer” (MAX)

• “cFP-PWM-520”



Thermocouple Input Module

• 8 channels of any type T/C

• Used for temperature monitoring of the three zone heaters

• Selection of T/C and Cal through MAX

• Uses isothermal connector blocks

• “cFP-TC-120”



Discrete Input Module

• 32 digital input channels• Compatible with 24VDC

sourcing-output devices• Used to read important

indicators, (e.g. vacuum seal, etc…)

• “cFP-DI-304”



Connector Blocks

• Two types:– “cFP-CB-1”– “cFP-CB-3”

• Connected to corresponding module through backplane

• Used to physically wire devices to cFP unit



cFP Hardware Setup

• NI Measurement and Automation Explorer– Will “see” any NI hardware on the network– Assign IP address– Set parameters– Ready to Go!


User Specified InputsFor cFP System


Components of the Real-Time Software

• “Drivers” for each cFP module• PID control blocks

– Needed to control temperature

• Program “step” code– Needed to take program through the logical sequence

of events required for a specific process

• Safety shutdown code– Temperature Overshoot– Zone Differential Exceeded– Manual Shutdown



cFP Module “Drivers” in LV 7.1



“Drivers” in Labview 8

• “Drivers” are much easier to implement in Labview 8.

• Labview 8 has “drag and drop” features which allow you to drag a specific channel of a device (along with it’s “drivers”) over to your VI from the project window.


Drag and Drop “Drivers” For Each Device Channel

Source: [1]


What is PID?

• Proportional-Integral-Derivative

PIDCompensator

SYSTEM+-

Desired Setpoint


PID Control Blocks

• Necessary for each zone of our temperature controller



High Level Program Flow Chart

User EntersTable Values

Start Program

Read InputsFrom cFP

Compare InputsTo Table

Activate DesiredOutputs

Set Center ZoneTemperature

Set DelayCounter

Compare DelayCounter to Zero

Increment RowCounter

Reset ColumnCounter

IncrementColumn Counter



Outer ZonesTrack Center

Zone Temperature

True

False

False

True


Program Step Code

• Reads Table

• Determines if input requirements are met

• Activates desired outputs

• Sets new temp

• Waits a desired time before next step


Program Table



Program Table Values• Decimal numbers correspond to a binary value which

represents I/O ports.• Example for a particular output step:

Actual = N2 NH3 H2SiCl2 GateValve A B C D Want = On OFF OFF On On Off On OnBinary = 1 0 0 1 1 0 1 1

10011011b = 155dTech enters 155 into table.• Independent number conversion needed to save memory

space onboard real-time controller. LabView Users Group Meeting June 20th, 2006


Control Panel

• Available on host PC and remote window.



Remote Panel

• Built in Web server.

• Monitor/control your application from a Web browser

• Advantage to user running a long duration process


Shared Variables

• Allows easy communication of data between Real-Time target VI and Host VI

• Save program memory onboard Real-Time target by conducting most processing tasks on board PC using Host VI

• Available only in Labview 8


Things To Remember About The Real-Time Software

• When you execute your program, it is downloaded and run on the Real-Time controller, not your PC!– This effects the size of your program and

ultimately limits the number of “bells and whistles” you can have


Summary

• Advantages of using cFP w/ LV Real-Time:– Very Flexible– Expandable– Relatively Easy to Understand– Simple Network Interface

• Disadvantages:– Limited Memory– Expensive



References[1] NI LabView Real-Time Hands-On Seminar Manual.

February 2006 Edition. Part Number 351171C-01

Additional ResourcesI. National Instruments: www.ni.com

II. Compact Field Point: http://www.ni.com/compactfieldpoint/

III. Labview Tour: http://www.ni.com/swf/labview/us/tour


Thank You!

Questions, Comments, and Suggestions Welcome!

Documents

LabView Users Group Meeting June 20 th, 2006 Process Control Using Compact Field Point/Labview Real-time Michael Tockstein Microelectronics Technology