The price of the split between S88 and S95

Transcription

1 Presented at the World Batch Forum European Conference Mechelen, Belgium October Fox Valley Drive, Suite 204 Longwood, FL Fax: The price of the split between S88 and S95 Author Name Title Company Address City, State Postal Code Country Telephone Number Fax Number address Siem Broersen Manager MES Expert Center GTI Industrial Automation P.O.Box AJ Zaandam Netherlands KEY WORDS The price of the split between S88 and S95 ABSTRACT There is a split between the S88 and S95 models. In the physical model of S95 procedures are not implemented. Why not use PFC for logistic procedures instead of BPML? Your engineers have to learn only one model. You can combine S88 and S95 to one physical model for batch, continuous and discrete processing including storage units. Copyright 2004 World Batch Forum. All rights reserved. Page 1

2 PAPER 1. Introduction Before S88 was introduced, many systems were built to solve the same problems as addressed by S88. Every system was build after an (good or bad) analysis of the real world problem. The analysis of the real world will always lead to model of a part of that real world. The real world is to complicated to model because of the following facts, The real world has infinite objects The real world has infinite relations So you compromise the real world into a restricted model. For batch automation the S88 standard was introduced for this purpose. S88 procedural model The S88 model is a success story. Nowadays most of the dosing systems are based on this model. The main reason for this success is that the main principle in S88, to have a physical model next to a procedure model, is easy to understand. On the other hand, every S88 system has its own data model. None of the available commercial systems is fully based on S88.02 data model. Therefore they are not truly S88 compatible but implement a subset of it. There is one principle all systems provide; a physical model and a With the introduction of S95, a new physical model was introduced. This new physical model, as described later, looks a lot like the S88 physical model, but there are some differences; S95 physical model has no relations S95 physical model stops at the unit level S95 physical model has no connection with the procedural level S95 model makes a difference between batch, continuous and discrete S95 adds storage zone s and modules (in part 3) Because of these differences, it is hard to make ONE model for the whole plant. In this way the engineer has to model the plant twice, one time from S88 perspective and one time from S95 perspective. After this he has created a SPLIT in the real world, and he has to make an artificial connection between the two models. This SPLIT between the two models will make modeling work harder to do! One physical model for S88 and S95 could solve this problem. Copyright 2004 World Batch Forum. All rights reserved. Page 2

3 2. The S88 model The S88 model is shown in the picture below. You can consider the physical model as a kitchen. You describe the lay out, your pots and pans, the oven, mixers and raw materials. Next to that you have your cook book which holds the recipes. These recipes will first tell you what raw materials and physical equipment you need and then give you a step by step unit procedure. Every step (phase) will tell you how to perform a specific step (equipment phase) on a Physical model Procedural model specific equipment (eg a mixing or a dosing step). The cook is your S88 computer system and is able to read the book and to control your kitchen. Some important classes are missing in S88 physical model The storage units. In many S88 systems storage is covered by the unit level. This can be done, but in many plants the storage is shared by several process cells. On most storage units, no procedural activity is needed, but license prices are often based on the number of units serviced. Production lines A process cell in S88 is not a production line, however a production line could be a process cell. Some S88 systems use the S88 concept train as a production line. Production line -1 Weighers Production line -2 If you have 2 production lines sharing one starting point (eg some weighers), in S88 you have to model this in one process cell. Mixer-1 Mixer-2 system. Buffer-1 Packing-1 Buffer-2 Packing-2 ERP Planning Bottleneck As an alternative, you could introduce shared units. The weighers can then be shared by both production lines. A production line is often a basic entity in a production planning system or ERP Copyright 2004 World Batch Forum. All rights reserved. Page 3

4 3. The S95 model After the successful introduction of the key-principle of S88, the team continued to work on the data models needed for integration with the ERP level. ERP level 4 systems, have a BOM (Bill of materials) and a BOO (Bill of Operations). Most of these ERP systems don t use a S88 procedure for the lay out of a recipe. (SAP has a PPPI module based on S88). As a result of this, S95 is based on a different physical model. Below you see the UML diagram of the physical model of S88. You can see that there is a connection from an equipment entity with the equipment procedural element. This is the connection between physical model and the procedural model. Copyright 2004 World Batch Forum. All rights reserved. Page 4

5 The S95 physical model looks like this In this model, the maintenance classes are added. On the other hand, the relations between the equipment entities are missing. Also the connection to the procedural model is left out! This split between the S95 and the S88 physical models makes the following questions hard to answer from a S95 perspective; How to determine if a production line is able to perform a specific activity (described by an equipment phase on a unit) How to determine the availability of a raw material on a production line. How to determine the interface of a specific activity (phase) How to determine a possible connection between units If you want to answer these questions from a S95 perspective, you have to model this information into the process segment model, but there you don t have an interface to the procedure. Copyright 2004 World Batch Forum. All rights reserved. Page 5

6 4. Modeling of the plant You could model the plant from a combination of S95 and the S88 model using the following approach; Use one physical model for your plant based on S88, including the procedure interface Use the storage units as an extra model, and specify storage units also having equipment modules and control modules. (heating, cooling, mixers, level transmitters etc.) Use PFC (described in S88.02) for the procedural model Make a S88 process cell equal to a production line (with shared units) Make a relation between a production line and a S95 process segment The concept of process segment is a planning view of production defining the resources needed for production. (S95-02) meal Meal Clean meal Meal Fill Silo Meal Silo Dough Tub Suger Suger Grind Suger Fill Silo Suger Silo Dough mixing Baking Packing Fat Fat Cool Down Fat tank Sirop Sirop tank Water tank bags Store Clean Buffers Premix Dosing Buffers Raw materials Intermediate Products Production Batch Oven Continuous Packing Discrete Every production line is a circle and can be considered as a S88 process cell which can be related or equaled to a process segment. The storage units (triangles) can be used as an interface between production lines. Discrete, continuous and batch processes can be modeled in one physical model. S88.02 PFC (Procedural Function Chart) is a perfect tool for modeling the workflow in a plant because of the direct standard interface to the physical model. Most S88 engines also have a standard Copyright 2004 World Batch Forum. All rights reserved. Page 6

7 resource allocation utility and possibilities to model shared equipment. BPML is another tool for work flow modeling, but the syntax is different. Data input start Parallel Condition Wait for all steps stop weighing Print label HACCP check Control Transport Print doc Lot release Pro PFC modeling Designed for process flow One model / language for the plant! Direct connection to the plant physical model o Production lines (= Process Cell) o Unit allocation o Equipment phase PLI interface o Control module states Allocation and synchronization Tracking & Tracing Open standard (S88-02) (Soft)Phases can execute any possible function! Pro BPML modeling Designed for workflow Extra graphical symbols for a more clear lay-out Multiple levels Pools and lanes structure Open standard Copyright 2004 World Batch Forum. All rights reserved. Page 7

8 5. Commercial Toolboxes There are commercial MES Toolboxes based on S88 and S95 on the market. One toolbox is e.g., based on the S88-02 data model with all physical levels included. This model is used for batch, continuous and discrete processes. The control module and equipment module level are used as an interface to the control level. Technical functionality Startup from a standard internet browser Full integration with intranet Process visualization, historical trending (SCADA functions) One user interface for all functions (depending on authorization) Platform independent (Windows NT, 2000, XP, Longhorn, Linux, Unix) Java based No runtime license, no dongles and no installation on the clients Based on S88 and S95 models Redundancy Open source MySQL database or MS-SQL server Process functionality procedure for raw materials Production order planning and scheduling of S95 segments Recipe management (PFC based of several segments) Material / stock management and storage unit management (tanks and silo s) Lot tracking and tracing Contamination check on production lines and units and integration of CIP procedures. Integration of HACCP procedures Handling and planning of manual dosing Control for batch, continuous and discrete processes. Visualisation of S88 objects S88 physical model as interface to control Copyright 2004 World Batch Forum. All rights reserved. Page 8