SATO Keiji1 MATSUNO Takuya1
Rapid progress in Information Technology has fueled the shift toward open architecture systems and networking in the manufacturing industry. However, even though IT has enabled data integration between systems, for surviving the global competition, it is essential to process such data strategically though closer collaboration between systems and to reform role-sharing between humans and systems. Therefore, we have newly developed and added VBScript Unit Procedures and user application unit procedures to "Exapilot" operation efficiency improvement package, thereby enabling users to tailor the icons of procedures to their needs. This upgrade facilitates interlinking of Exapilot with other systems, and then turning Exapilot into the core software in collaborative operation packages. This paper introduces a predictive control system as an example of collaboration using Exa Series solution-based packages.
Remarkable progress in information technology has led to open architecture systems and networking in the manufacturing industry. In such industry, remote monitoring systems based on public communication lines or the Internet, and or collaboration of control, information, and corporate systems based on standardized interfaces such as OLE for Process Control (OPC) are now widely used via networks. Despite such data integration between systems, however, closer collaboration and processing of data for strategic use, and changes in role-sharing between humans and systems are needed in order to survive the global competition.
This paper introduces an approach for closer collaboration of systems using the Exapilot operation efficiency improvement package.
Our customers use various systems in their actual manufacturing plants, including:
These systems were developed to meet respective user needs, and have since become an essential part to keep day-to-day production activities. However, users need to increase operation and production efficiency, at lower cost and with shorter lead times in the age of surviving the global competition. One approach is for our system integrators to link and coordinate existing independent systems and configure the systems enabling the production based on speed up and more accurate decisions to be made. We call this type of efficient production with close collaboration among existing systems "operation support collaboration."
Figure 1 shows the concept of this collaboration. Exapilot is a software package designed to automate the work of humans (operators). With functions for collaborating with other systems added, Exapilot becomes core software for operations.
Figure 1 Concept of Operation Support Collaboration
|Figure 2 Defining an Operation
Flow in Exapilot
Exapilot is a software package that enables plant operator to computerize their knowledge of plant operations by themselves. To do this, they only put the icons of unit procedures corresponding to particular actions, such as plant operations including data setting in a control system, plant anomaly monitoring, and manual operation request to the site, to draw a flowchart as shown in Figure 2. For example, the following are routine tasks of the operator:
Exapilot makes it easy to interface with the control system, but the VBScript unit procedures newly added in Exapilot R3.10 make it even easier: the entire six-step procedure shown above can be performed by Exapilot, and thereby leaving the operator free to focus on more important work instead.
VBScript Unit Procedures
|Sub lag ()
ARG03 = ARG04*exp (-1/ARG02) + (1 - exp(-1/ARG02))*ARG01
ARG04 = ARG03
'DATA_IN : ARG01
'TIME : ARG02
'DATA_OUT : ARG03 'DATA_PRE : ARG04
|Figure 3 VBScript of First Order Lag|
Visual Basic (VB) is a widely-used programming language, and VBScript (VBS) is a compact and easier-to-use version of Visual Basic. VBScript unit procedures enable users to add custom functions to Exapilot by themselves.
Examples of collaboration by VBScript are introduced below.
User Application Unit Procedures
dispname=first order lag
|Figure 4 Information File for
Unit Procedure of First Order Lag
Nevertheless, VBScript is still a programming language and is not always intuitive for those directly involved in manufacturing. Exapilot therefore allows users to easily add functions that they have developed as VBScripts, as custom unit procedures which are referred to as "user application unit procedures".
An example of creating a user application unit procedure having a first order lag, which is often used in control calculations, is shown below. The transfer function of a first order lag can be expressed as:
G(s) = k/(1 + Ts)
Transforming this expression for digital control systems yields:
DATA_OUT = DATA_PRE * exp(-1/TIME) DATA_OUT + (1- exp(-1/TIME)) * DATA_IN
DATA_IN = input value
TIME = time constant
DATA_OUT = output value
DATA_PRE = preceding output value
To create this unit procedure of a first order lag, the user only has to create a script file and unit procedure information file and to put them in a designated folder.
|Figure 5 Dialog Box for Defining
Unit Procedure of First Order Lag
As an example of operation support collaboration, a predictive control system comprised of Exa Series solution-based packages is described (see Figure 6). This system predicts future values of specific process data using a multivariable model, performs anomaly monitoring on the data thus predicted, and gives instructions to the operator to avoid future abnormalities. This ensures steady, safer plant operation and hence more efficient production. The Exa Series solution-based packages of this system have the following roles:
Figure 6 Predictive Control System
We have been developing software that assists collaboration for the benefit of users as well as software developers in terms of quicker development with fewer resources. VBScript is not new, but as with Web services on the Internet, can be used to improve collaborative functinalities. We will continue to incorporate the latest technologies into Exapilot to extend such collaboration.
Procedural Automation (Exapilot) provides a flexible methodology to capture, optimize and retain procedural knowledge in a process plant while meeting requirements in reliability, flexibility, and lifecycle costs.