Project Description

The project consisted of replacing the following control systems on an existing two-stand aluminum cold mill:

• Feedforward and feedback automatic gauge controls (AGC)
• Interstand tension control (ITC)
• Automatic sheet flatness control (AFC)
• Mill setup
• Entry and exit x-ray thickness gauge interfaces
• Mill stand hydraulic actuator sequencing
• Human-machine interface (HMI) for supervisory control functions

Implementation of the existing systems was distributed over several computers and custom-designed discrete hardware control panels as follows:

• The existing AFC, recipe-based mill setup, and mill stand sequencing functions were implemented in special-purpose computing hardware, programmed in assembly language. The customer had no up-to-date program listings and there were no on-site program development tools for this system.
• The existing HMI was implemented in the AFC computer and utilized a proprietary video display terminal with special function keyboard. HMI software was programmed in assembly language.
• The AGC and ITC systems were implemented in the Reliance Automax mill drive controllers.
• Hydraulic gap control (HGC) and work roll bending pressure regulation were performed by discrete hardware with target reference generation by the mill drive controllers.
• Pulse modulation of multi-zone roll cooling sprays was performed by the mill drive controllers.
• System sequencing was implemented as ladder logic in the mill drive controllers.

Only mechanical equipment drawings existed; there were no control system design drawings.

The mill rolls a wide variety of products, including 3XXX, 5XXX, and 6XXX aluminum alloys at exit gauges down to 0.0055 inch. It is the only cold mill in the plant and makes all breakdown, intermediate and finish passes. Incoming stock consists of continuous-cast hot band produced locally or acquired externally, as well as conventional reroll hot band coils.

The objectives of the control system upgrade project were to:

• Migrate setup, control and HMI functions implemented in obsolete computer hardware to a single off-the-shelf, open-architecture platform.
• Implement all system software in a standard, high-level language.
• Eliminate obsolete computer hardware.
• Interface to new entry and exit x-ray thickness gauges.
• Replace the existing table-based mill setup system with a general-purpose, model-based setup function.
• Integrate the new controls with existing mill drive and actuator device controls to be retained.
• Minimize field wiring changes by utilizing the existing Reliance Automax mill drive control I/O.
• Introduce maintenance and diagnostic tools to improve data collection and troubleshooting capability.
• Introduce mill quality and performance monitoring tools.
• Interface to existing MIS business systems.

The contract was issued in August 2002. Commissioning was completed in January 2003 (performed during the planned outage for new x-ray gauge installation).

Project Approach

TelePro completed development and testing in five months. This included the following activities:

• Preliminary engineering study / system requirements definition.
• Detailed system design specification.
• Design of reflective memory interface to existing Reliance drive controls.
• Process control computer installation on site - live inputs / parallel run configuration.
• On-site integration test and HMI workstation installation.
• Trial rolling one month prior to commissioning outage, using the original x-ray gauges.
• Commissioning following the gauge replacement outage.

The preliminary engineering study was conducted to define system functional requirements. This included specification of all external interfaces with people, the process, and other system elements. During this phase of the project, the design for integrating new and existing systems was developed. Based on results of the preliminary engineering study, a design review was conducted with the customer prior to proceeding with development work. The project schedule containing key activity completion and information exchange milestones was then generated.

Trial rolling involved live testing of the new setup system and new controls. This activity was inserted into the schedule to reduce the risk of startup problems following the gauge replacement outage. It was used to verify new system operation before the old computer hardware was removed. It also allowed the new controls to be checked out prior to replacement of the x-ray gauge hardware.

System Architecture

The customer specified primary and redundant backup control system host computers with uninterruptible power supply (UPS). Each of these systems hosts gauge, tension and flatness controls, mill setup and model adaption, x-ray gauge setup interfaces, mill stand sequencing, process quality/performance monitoring, and HMI display functions.

The control host computing platform is the TelePro TSENTRY product. It consists of an off-the-shelf IBM-compatible personal computer running the Windows 2000 Server® operating system with VenturCom RTX® real time extensions. This system comes complete with all facilities required to support deterministic real-time program repetition rates as fast as 1 millisecond.

All hardware consists of industry-standard, open-architecture systems commercially available from multiple equipment suppliers. Communication is via industry-standard TCP/IP protocol over ETHERNET. Application software is implemented in the ANSI / ISO Standard C and C++ programming languages.

The TSENTRY computing platform runs on a standard IBM-compatible personal computer. For this project, the customer's project engineer and MIS manager selected the following PC server configuration for the host computer:

• 2.0 GHz Intel Xeon CPU, 512 MB memory, CDRW drive, 3.5" diskette
• 30 GByte hard disks
• 2 ETHERNET controllers:
• Backplane, Intel PRO 10/100 for process LAN
• 3COM 3C905-TX for process I/O LAN
• RAID disk system configured per customer requirements.

The host systems include mirrored disk configurations specified by the customer according to local requirements. TelePro added system and application-specific software. System software includes:

• Microsoft Visual Studio® software development environment
• VenturCom RTX® real-time operating system extensions
• TelePro TSENTRY real-time process control system libraries
• Microsoft Terminal Services
• Symantec PCAnywhere

Performance tests were conducted for an extended period of time to verify system reliability.

The system architecture is shown in Figure 1:

Figure 1: System Architecture

In addition to performing process control functions, the TSENTRY system includes both real-time and historical trending. TSENTRY also provides a general-purpose real-time computing platform that includes all facilities and libraries required to allow the end user to develop and implement custom process monitoring, control, signal processing, and human-machine interface (HMI) applications. This system interfaces to several varieties of process I/O hardware and is capable of performing all process control and human-machine interface functions required for mill control. It was developed specifically as a real-time process control system platform.

Graphical HMI/Engineering workstation displays are implemented as standard Internet web pages hosted by the TSENTRY system. The standard TSENTRY product includes all facilities required to develop and support a human-machine interface system based on standard web pages. These facilities include custom controls for building animated displays with Microsoft Visual Basic 6.0. Automated processes are included for building web screens to execute the controls and for publishing the controls to client workstations. Any network-connected PC workstation with a standard web browser and proper security credentials can be used as an HMI client.

The automation architecture permits remote technical support through a secure ETHERNET connection. To enable remote support, the customer provided an ETHERNET LAN connection available to a trusted external site and a bridge to isolate the process control computers from the rest of the LAN.

Scheduling System Interface

The TSENTRY process control host computer receives coil information directly from the customer's MIS scheduling system. The MIS system creates a schedule data file containing one record for each coil in the rolling schedule. This record contains pass specification target information required to set up the entry and exit x-ray gauges, as well as the mill control systems. It also contains information required to run the mill setup models. This data includes:

• Production practice number
• Aluminum Association alloy designation
• Entry strip width (in.)
• Trimmed strip width (in.)
• Pass number
• Entry / interstand / and exit gauges (in.)
• Entry / interstand / and exit tensions (psi)
• Strip speed at rewind (fpm)
• Gauge at last anneal (in.)
• Coil composition data for x-ray gauge setup

The MIS system transfers the schedule data file to the TSENTRY host. The file is updated periodically as new schedule information becomes available.

To select the next coil in the schedule for processing, the mill operator enters the coil identification number and pass number into an HMI display screen. The TSENTRY system searches the MIS schedule file for the corresponding information. This information is retrieved and displayed on the HMI screen for verification. The operator has the option of modifying the data prior to verification. If the requested information is not available from the schedule data file, the operator can enter the required information directly on the screen. The operator indicates that the coil information has been verified by clicking on a "Data Verified" screen button. The data is then be used to set up the mill prior to the start of the next coil.

Model-Based Mill Setup

The mill setup system consists of model-based actuator preset calculation systems for both thickness and flatness. Adaptation of the roll force and strip shape models is provided by means of short- and long-term parameter recalculation loops.

The mill setup system includes the following functions and features:

• A network interface to the plant production planning and scheduling system for receiving rolling schedule data.
• A local rolling practice database specific to the target mill for defining and maintaining product-dependent practice information such as special threading practices, strip tension setpoints, reduction schedules, target flatness distributions, etc.
• A local material properties database with maintenance tools.
• Facilities for allowing the mill operator to modify certain schedule and rolling practice parameters via an HMI workstation at the operator's desk.
• Force, torque, and extrusion models based on conventional cold rolling technology.
• Roll stack deformation and strip shape models based on TelePro extensions to conventional profile and shape model technology: These models consist of high-speed, full-width, discrete vector calculations of roll gap profile and exit strip tension distributions as functions of predicted separating force, assumed incoming strip profile, total roll crown (ground plus estimated thermal crown), and work roll bending forces.
• Facilities for using the process models to calculate product-dependent actuator sensitivities used by the AGC, ITC and AFC functions.
• Error tracing and diagnostic support functions.
• Secure, remote access to model parameter databases, HMI displays, diagnostic support information, and performance data via standard network connection.
• Support for automatic mill setup through transfer of actuator setup targets to the existing mill drive controls via reflective memory interface.
• Facilities for using the setup system models for off-line analysis and product/practice development.

The setup model adaption system includes the following functions and features:

• Actual value data collection at a known stable operating condition.
• Roll force model adaption based on roll bite friction recalculation.
• Stack deflection/strip shape model adaption based on recalculation of the full-width thermal crown vector.
• Short-term adaption in which model parameters (friction and thermal crown estimates) are updated for the next coil to be rolled, based on recalculation results from the previous coil. The short-term adaptation results are only used if the next coil to be rolled is of the same product specification as that used for recalculation. Otherwise, they are discarded.
• Long-term adaptation in which nominal shifts in the model parameters over several coils of the same product specification are stored in the material properties database, to be retrieved each time the product specification is rolled.

Automatic Gauge and Interstand Tension Controls (AGC / ITC)

The TelePro AGC system consists of a basic delay-compensating feedback control algorithm requiring only exit thickness and main motor speed measurements. Enhanced mass flow and gaugemeter control loops requiring additional process measurements, as well as feedforward control, are also included. The various components of the AGC system are all fully integrated. This means that bumpless transition mechanisms are provided for changing between modes while rolling.

The ITC system consists of separate control modes for initial mill threading and steady-state rolling. The threading control mode is configured specifically to establish interstand tension during initial threading. The steady-state or run control mode is configured to reduce interactions between interstand tension and strip thickness.

The AGC / ITC systems utilize non-interactive actuator networks -- combinations of simultaneous stand speed and roll gap position changes which decouple strip thickness and tension changes. An AGC load sharing mechanism is also included to permit thickness corrections to be distributed over all available rolling stands according to a prescribed loading ratio. Product-dependent actuator sensitivities are computed by the mill setup models for each gauge and tension control actuator. These sensitivities determine the relative size and direction of the actuator movements required to reduce interactions between the tension and gauge control loops.

The control software is implemented in the ANSI Standard C and C++ programming languages.

The AGC / ITC systems include the following functions and features:

• A delay-compensating feedback AGC algorithm that produces the fastest possible closed-loop performance in the presence of material transportation delay in the feedback measurement. Controller gains are calculated continuously to optimize response at every rolling speed.
• Additional feedback AGC control algorithms based on mass-flow and gaugemeter estimates of strip thickness. A bumpless transition mechanism is provided for switching between feedback AGC modes while rolling.
• A feedforward AGC control algorithm which employs entry thickness deviation and entry sheet speed measurements to improve AGC disturbance rejection performance for incoming thickness variations.
• A thread mode tension controller specifically designed to establish interstand tensions during initial threading. The output of the thread mode controller consists of changes to stand motor speeds.
• A steady-state run mode tension controller optimized for operation once all tensions have been established. The output of the run mode controller consists of simultaneous changes to roll gaps (or HGC pressures) and stand motor speeds to permit interstand tension corrections without causing thickness changes.
• Product-dependent actuator sensitivities calculated by process models are used to adapt the AGC / ITC systems for various product hardnesses, widths and gauges.
• Entry and exit thickness deviation input signals are acquired through dedicated high-speed analog inputs in order to minimize signal latency. All other AGC / ITC process inputs are received via real-time reflective memory interface to the existing mill drive controls.
• Outputs to the HGC position/pressure regulation and stand motor drive controls are via real-time reflective memory interface to the existing mill drive controls.
• Maintenance and diagnostic support tools are provided for monitoring the condition of key control functions. These include graphical controller monitoring displays showing the controller functional block diagrams with current values of important inputs, outputs, internal variables, and activation logic, updated in real time on the screen. Authorized personnel can modify certain system parameters on line through the screen.
• A high-speed, real-time trend system, including tools for displaying and/or modifying any global system variable by name through an engineering workstation. Both graphical and tabular data display are provided.
• Secure, remote access to the diagnostic support displays via standard network connection.

Automatic Flatness Control (AFC)

The TelePro AFC system consists of integrated control of work roll bending, HGC tilting, and multi-zone work roll cooling to minimize deviations between target and measured exit strip stress distributions. System software is implemented in the ANSI / ISO Standard C and C++ programming languages.

The AFC system includes the following functions and features:

• Product-dependent flatness actuator influence sensitivities calculated for each coil using fully-discretized roll stack deflection and strip shape models.
• Model-based decoupling of mechanical bending and tilt actuator controls from the multi-zone spray control.
• Multi-zone spray controls consisting of both residual shape and average spray level controllers.
• Delay-compensating feedback control algorithms that continuously calculate controller gains to optimize system response at every rolling speed.
• Feedforward bending control based on separating force changes using fully discretized shape influence vectors to improve bending control during acceleration and deceleration and when changing gauge at coil heads and tails.
• Product-dependent selection of preset spray pattern, average spray target level, and exit stress distribution target.
• Process inputs, including shapemeter feedback, work roll bending pressures, and HGC cylinder positions and pressures, are received via real-time reflective memory interface to the existing mill drive controls.
• Outputs to the work roll bending, HGC tilting, and work roll zone cooling device controls are via real-time reflective memory interface to the existing mill drive controls.
• Maintenance and diagnostic support tools are provided for monitoring the condition of key control functions. These include graphical controller monitoring displays showing the controller functional block diagrams with current values of important inputs, outputs, internal variables, and activation logic, updated in real time on the screen. Authorized personnel can modify certain system parameters on line through the screen.
• A high-speed, real-time trend system, including tools for displaying and/or modifying any global system variable by name through an engineering workstation. Both graphical and tabular data display are provided.
• Secure, remote access to the diagnostic support displays via standard network connection.
• Graphical operator's display showing target and actual measured exit stress distributions, work roll zone spray flow levels, entry and exit thickness deviation trend plots, roll bending and HGC tilt feedback, separating force, mill speed, and other process variables. This display is updated once per second. An sample operator's display is shown in Figure 2 below:

Figure 2: Operator's Flatness Display

Graphical HMI / Maintenance Support Displays

Graphical HMI and maintenance support displays are implemented as standard Internet web pages hosted by the TSENTRY control host computer. Any network-connected PC workstation with a standard web browser and proper security credentials can be used as an HMI client. This permits any HMI display to be accessed from any workstation within the cold mill complex.

Displays are developed using a combination of Microsoft Visual Basic 6.0 and Active Server Pages. Complete facilities for developing and publishing custom HMI displays are provided to the end user.

In addition to the display unit installed in the operator's pulpit, additional HMI workstations were installed at the coil loading and unloading stations and in the mill computer room. Any of these workstations can be used to display the operator's display as well as any of the controller monitoring screens. An additional networked display unit was located in the area engineer's office.

Examples of the graphical controller monitoring displays associated with AFC are shown in the Figures 3 through 5. Figure 3 is the top-level work roll bending controller block diagram display. Figure 4 shows internal data for the work roll bending PID controller. Figure 5 shows the AFC activation logic.

Examples of the displays for AGC are shown in the Figures 6 through 8. Figure 6 is the top-level feedback AGC block diagram display. Figure 7 shows the delay-compensating control algorithm. Figure 8 shows the feedback AGC activation logic.

The completed system consists of approximately 60 HMI and system monitoring/support displays.

Figure 3: AFC Work Roll Bending Controller

In the diagram above:

• Clicking on various portions of the diagram with a mouse device provides additional levels of detail. For example, clicking on the box marked "PID Control" produces the display shown in Figure 4.
• Gain K_S is a commissioning value with nominal value 1.0 which can be changed directly on the display.
• Other values displayed on yellow backgrounds are data entry as well as display fields on the screen. Security is provided to assure that only authorized personnel are permitted to make parameter changes.
• The function buttons at the lower left of the screen switch to other system displays.
• Boxes at the lower right of the display are real-time variable trend plots and vector displays of critical controller variables.

Figure 4: AFC Work Roll Bending PID

In the diagram above:

• Gains K_P, K_I, and K_D are controller parameters calculated continuously as functions of actuator response dynamics, mill speed, and desired closed-loop response.
• Gains C_P, C_I, and C_D are commissioning values with nominal value 1.0 which can be changed directly on the display.

Figure 5: AFC Activation Logic Display

In the diagram above:

• True states are indicated by filling the associated box (for inputs) or circle (for outputs) with green. False states are indicated with red.
• The state of the maintenance enable logical can be changed by clicking with a mouse device directly on the state indicator.

Figure 6: Feedback AGC: Top Level

In the diagram above:

• Clicking on various portions of the diagram with a mouse device provides additional levels of detail. For example, clicking on the box marked "Feedback AGC" produces the display shown in Figure 7.
• Gain K_S is a commissioning value with nominal value 1.0 which can be changed directly on the display.
• Other values displayed on yellow backgrounds are data entry as well as display fields on the screen. Security is provided to assure that only authorized personnel are permitted to make parameter changes.
• The function buttons at the lower left of the screen switch to other system displays.
• The box at the lower right of the display is a real-time variable trend plot of a critical controller variable.

Figure 7: Feedback AGC Controller

In the diagram above:

• Clicking on the box marked "Monitor PID" displays additional levels of algorithm detail.
• The box at the lower right of the display is a real-time variable trend plot of a critical controller variable.

Figure 8: Feedback AGC Activation Logic

In the diagram above:

• True states are indicated by filling the associated box (for inputs) or circle (for outputs) with green. False states are indicated with red.
• The state of the maintenance enable logical can be changed by clicking with a mouse device directly on the state indicator.

Real-Time / Historical Trend Facility

The TSENTRY computing platform provides a real-time / historical data trend facility which supports Internet web page based editing and display of process variables. Data may be displayed and edited from a browser run on the system console or on any networked Windows 2000â workstation. Both graphical and tabular data displays are provided.

The real-time / historical trend system includes the following functions and features:

• Access by name to any process variable in host global shared memory by means of a data dictionary.
• Data dictionary build process. This process automatically updates the global shared memory data dictionary when new variables are added to the system and old ones are deleted.
• Real-time trend data acquisition. Data is acquired at a 20-millisecond rate (50 samples per second per point) and made available for display on networked HMI / maintenance support workstations.
• Real-time trend data display. Web page screens are provided for graphical and tabular display of high-speed, real-time data.
• Display pan and zoom features.
• Trend data can be exported as individual Windows files.
• Storage, retrieval, and editing of trend set files, which define graphical and tabular data display configurations: variable names, scaling, display attributes.
• Dynamic trend display editing allows interactive modification of trended variable names, time scales, signal magnitude scales, and text display formats.
• Historical trend display integrated with real-time trend displays.
• Facilities for starting and stopping historical trend data acquisition based on user-defined trigger events.
• Support for multiple variable types: floats, integers, character strings, Booleans.
• Multiple value display formats: float, character, decimal integer, hexadecimal integer, and binary.
• Process variable "Probe" screen. A web page is provided for displaying and modifying any process variable in shared memory by name. The screen is accessible from a web browser run on the system console or on any networked Windows 2000â workstation. Data write access can be password protected.
• Process variable "ProbeA" screen. Same functionality as "Probe" for multidimensional array data objects.
• Process variable "TrendX" screen. View up to 24 simultaneous signal trends in real time on up to six independent Y axes.

Examples of the Probe, ProbeA, and TrendX screens are shown in the Figures 9 and 10.

Figure 9: Process Variable "Probe" Screen

Figure 10: Process Variable "TRENDX" Screen

X-ray Gauge Setup Interface

TelePro provided software for communicating with the new x-ray gauges via TCP/IP protocol over ETHERNET. This interface is used to configure the gauges before each coil is processed. The TCP/IP interface is also used to control gauge functions such as on-sheet and off-sheet movements, standardization requests, and open/close shutter. Operation of this interface was verified at the x-ray gauge supplier's factory prior to on-site installation of the gauges.

The gauges generate actual entry and exit thickness deviation feedback as +/- 10 VDC analog signals. The original feedforward AGC scanned entry thickness deviation samples every 20 milliseconds directly from the x-ray gauge hardware, without additional data transfer latency. In order to assure that the TSENTRY system received updates at the same rate, and without latency, entry and exit thickness deviation input signals are acquired through dedicated high-speed analog inputs.

Thickness and Flatness Performance Monitor (TFM)

This system performs real-time thickness and flatness performance data collection for the entire length of each coil. The data is archived in individual files for each coil. It can be plotted in real time, as the coil is running, or off-line from the historical archive files.

The application software is implemented in the ANSI / ISO Standard C and C++ programming languages. The TFM function is performed by the TSENTRY process control host computer hardware.

For each coil rolled, the TFM system collects the following static information from global shared memory in the process control computer and saves it to the archive file for the coil:

• coil identification number,
• material grade or alloy designation,
• product code or other customer application data,
• effective thickness at which the material was last annealed,
• scheduled entry, interstand and exit thicknesses,
• strip width,
• coil start and end dates / times, and
• diameters and identification numbers for all work and backup rolls.

During rolling the TFM system reads the following process signals from global shared memory in the process control computer:

• shapemeter feedback: 1-second samples of zone measurements across the strip width,
• entry and exit thickness deviation signals (sampled every 20 milliseconds),
• additional process signals sampled once per second:
  • flatness target curve parameters,
  • work roll bending forces (or pressures),
  • HGC average and tilt (differential) positions,
  • roll separating forces (or HGC pressures),
  • stand speeds.

The TPM system includes the following functions and features:

• Multiple power spectral density calculations are made for the 20-millisecond entry and exit thickness deviation signals. These power spectra are computed continuously over the entire coil length using the Fast Fourier Transform (FFT).
• Thickness performance summary statistics are calculated for each coil, including the standard deviation of both entry and exit thickness measurements.
• Each power spectrum computed during a coil and each one-second sample of the process signals, including the shapemeter feedback vector scan, is written to an archive file for the coil. This file can be accessed off-line to view graphical and tabular displays of the data. The data are also written to a standard relational database for access by external systems for custom analysis.
• The data can be viewed in real time, as the coil is running, or off-line from the archive files. Data displays are implemented as standard Internet web pages allowing display on any network-connected client using a standard web browser. Examples of the TFM data displays are shown in Figures 12 through 16 below.

Figure 12 shows two thickness deviation power spectrum "waterfall" plots. Each waterfall plot shows all of the power spectra calculated during the rolling of a single coil. The spectra calculated through the coil length are stacked one behind the other to produce the 3D plot. The waterfall plot not only shows the frequency components containing the thickness deviation power, but also shows whether the magnitudes of these components change through the coil length. Roll identification numbers, diameters and rotational frequencies are also shown on the display.

Figure 12: Power Spectrum Waterfall Plots

Figure 13 shows time series plots of the thickness deviation signals and mill speed, along with roll identification numbers and diameters.

Figure 13: TFM Time Series Plots

Figure 14 shows a time series plot of the thickness deviation signals and other process variables, including: sheet speeds, work roll speeds, tensions, extrusion ratios and actuator settings.

Figure 14: TFM Time Series Plots

Figure 15 is an example of a thickness and flatness performance summary for a coil. In this example, the flatness measurement scans collected through the coil are plotted on a single 2D surface plot representing the entire coil. The entry and exit gauge trend plots are shown below the surface plot.

Figure 15: Thickness / Flatness Performance Summary

Figure 16 shows a 3D surface plot representing flatness through an entire coil. The beginning of the coil is at the left of the plot.

Figure 16: 3D Flatness Performance Plot

Conclusion

The complete system was commissioned on schedule during the x-ray gauge replacement outage in early January 2003. Beginning with the first full month of system operation, the mill has met or exceeded its production goal every month. Prior to the system upgrade, the mill did not consistently achieve goal.

The system provides reliable operation across a wide range of product and process conditions. Because most of the direct operational interface was not changed, mill operators quickly adapted to working with the new system. Area maintenance and engineering personnel have been trained to diagnose most device-level faults using the activation logic screens and real time signal trending facilities. The controller monitoring screens have been used to train maintenance and engineering personnel on basic AGC/ITC/AFC system theory and operation.

Specifically, this system has provided:

• Reliable process control system operation.
• Improved product flatness, particularly with respect to edge zone control.
• Direct interface to the plant MIS business system.
• Seamless integration of new process control, new x-ray thickness gauges, and existing mill drive controls.
• Automatic system adaptation as a function of product characteristics: width, reduction, material grade.
• Improved process and system understanding on the part of operating, maintenance, and engineering personnel.
• Improved maintenance and diagnostic tools.
• Comprehensive quality and performance monitoring tools.
• Inexpensive, standard hardware available from multiple sources.
• Standard communication protocols and programming languages.
• Ease of expansion to support additional automation and data collection functions.
• Minimal impact of adding additional HMI / Engineering workstations.

The mill returned to producing prime-quality material two shifts after the changeover. Fine tuning by TelePro commissioning engineers continued for one week following initial startup. Since commissioning, no additional site visits have been required to support the system. All fine tuning and additional technical support have been provided using a secure ETHERNET LAN connection managed by the customer.

This system consists of standard TelePro rolling process control products tailored to the needs of this specific customer. The use of proven automation products permitted the system to be engineered, developed, delivered and commissioned in five calendar months. Areas of customization include: system sequencing, operator interface requirements, maintenance and diagnostic support tools, mill-specific equipment interfaces, and the plant scheduling interface. The use of standard, open-architecture system components allows for configuration flexibility and eliminates special-purpose hardware/software.