Batch processing is a very integral part of industrial automation. As manufacturing usually happens in batches, how to manage them is a very important task. That is why international bodies have developed rules and regulations for companies to follow when doing batch processing and production. Two such rules widely used related to batch manufacturing are ISA-88 and ISA-95. Both are widely distinguished in operation and need a clear understanding before implementing. In this post, we will see the difference between ISA-88 and ISA-95.
What is the batch manufacturing process in industrial automation?
First, let us understand what batch manufacturing is. Simply, consider a case where you daily manufacture 10 batches of a liquid juice, each batch containing 200 bottles. Each batch has the same process and steps, with only a variation in the recipe. Means, out of 10, 5 are orange juices and 5 are mango juices.
So, the operator needs to properly define the following data in a batch:
- Recipe name and ID
- Material of the ingredients
- Equipment or device types needed
- Process steps
- Setpoints and tolerance bands
- Start time and stop time
- Officer e-signature
With all this data, a batch of your choice can be defined. The program of operations will be the same; only your input data will vary. This is called batch manufacturing. ISA-88 and ISA-95 are related to this batch processing. Let us now see it in detail further.
What is the ISA-88 standard?
ISA-88 is a batch control standard that is derived from IEC 61512. It focuses on how a batch must be executed in a plant, and in a repetitive manner, by taking proper input data for the required batch. Not only execution, but it also defines how that batch must be designed and documented properly.
The standard is divided into the following parts:
- Modular model:
The modular module comprises a control module, an equipment module, and a unit module. In our example before, a pump that sucks juice from the flavour tank is a control module; a total of two pumps will make the equipment module and the tanks present in the plant, which are static and are responsible for making a product, make the unit module.
- Recipe model:
The recipe model comprises general, site, master, and control recipes. In simple terms, the juice manufacturer will lay a standard rule for manufacturing the juice, which makes the general recipe. The production team or the site (factory) team will fine-tune the recipe based on the available products, which makes the site recipe. Their engineers will then fine-tune the recipe or the secret style for making the finished product exactly, which makes the master recipe. Then, all the production batches will be made in a total recipe, which makes the control recipe.
- Process model:
The process model comprises the full-fledged steps on how to execute the batch from start to end. The logic is written in PLC or some other controller, and executes the process accordingly. Suppose there are 15 steps to prepare a single batch of juice; then each step is executed phase by phase for a given time and set values.
So, in short, the ISA-88 standard deals with ground level to prepare the batch properly. In automation terms, it works with L1 and L2 levels of PLC and HMI/SCADA.
The final points that must be complied with in this standard by the industry are:
- Ensure that the three models discussed earlier are structured first.
- Ensuring that each recipe has proper structure.
- Ensuring that each operation and phase is defined accordingly, and displayed on the SCADA screen as a step is executed.
- The graphics should show all currently executing steps and pending cycle times.
- The SCADA should have properly configured alarms, trends, and an audit trail for tracking the batch accurately.
What is the ISA-95 Standard?
ISA-95 is a standard for integrating enterprise and control systems, and it is internationally harmonized with IEC 62264. It focuses on how production orders and business demands are communicated from enterprise systems to manufacturing systems. Basically, it is the link between production and business. In automation terms, it deals with IoT, ERP, and MES levels, which work on enterprise blocks and function directly as per the demands from business teams and customers. This standard thus helps in maintaining the production business fluently as per demand, and also ensures that the product is delivered only if ISA-88 is met first by the production team.
ERP, MES, and other cloud services will input data to the SCADA system, triggering batch demand and the number of quantities to produce. So, according to the demand, the who, how, and when for the batch will be declared from higher levels to the batch processing team. The final points that must be complied with in this standard by the industry are:
- Ensure that ISA-88 is followed.
- Establishment of connectivity between ERP or MES and the SCADA system.
- Define ERP or MES parameters like data analysis, production information, and network connectivity.
ISA-88 vs ISA-95
| ISA-88 | ISA-95 |
|---|---|
| ISA-88 defines a standard for batch process control in manufacturing systems. | ISA-95 defines a standard for integrating enterprise and control systems. |
| ISA-88 focuses on batch process modeling, control recipes, and procedural control. | ISA-95 focuses on information exchange between business systems (ERP) and manufacturing systems (MES). |
| ISA-95 supports seamless data flow from the shop floor to top floor. | ISA-95 is applicable across all manufacturing industries for vertical integration. |
| ISA-88 defines process control models such as physical, procedural, and recipe models. | ISA-88 is mainly used for industries involving batch processing, like pharma, food, and chemicals. |
| ISA-88 provides modular, reusable process control structures. | ISA-95 provides standardized data exchange interfaces for MES and ERP systems. |
| ISA-88 separates the control strategy from equipment configuration. | ISA-95 separates business planning and logistics from manufacturing operations. |
| ISA-88 improves batch automation, recipe management, and process flexibility. | ISA-95 improves communication between enterprise systems and plant-floor systems. |
| ISA-88 includes concepts like Unit Procedure, Operation, and Phase. | ISA-95 includes levels of automation hierarchy (Level 0 to Level 4) for integration. |
| ISA-88 is ideal for defining automation logic in batch processing systems. | ISA-95 is ideal for aligning plant-floor operations with enterprise resource planning (ERP). |
| ISA-88 ensures standardization in batch system design and implementation. | ISA-95 ensures standardization in data exchange and operational hierarchy. |
| ISA-88 supports recipe-based execution and equipment independence. | ISA-88 provides a clear structure for the batch process lifecycle. |
| ISA-88 is implemented mainly at the control system level (PLC, DCS). | ISA-95 bridges the gap between control systems and business systems. |
| ISA-88 helps reduce engineering efforts and improves system scalability. | ISA-95 helps in consistent and scalable enterprise-manufacturing system integration. |
| ISA-88 provides a clear structure for batch process lifecycle. | ISA-95 provides a model to map business and manufacturing activities effectively. |
| ISA-88 standard is formally titled “Batch Control Part 1: Models and Terminology.” | ISA-95 standard is formally titled “Enterprise-Control System Integration.” |
ISA-88 works at a lower level of batch production, whereas ISA-95 works at a higher level of batch management with business.
ISA-88 deals in a detailed level of recipe management, whereas ISA-95 deals in a detailed level of ERP and MES functionalities.
In the automation pyramid, ISA-88 works at L1 and L2 levels, whereas ISA-95 works at L3 and L4 levels.
ISA-88 complies with the production department, whereas ISA-95 complies with the logistics and business department.
Refer to the image below for more details.
In this way, we saw the difference between ISA-88 and ISA-95.
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