Characteristic-Based Process Instructions Structure 
Use
When maintaining characteristic-based process instructions, you must define certain characteristics in a particular sequence according to the process instruction type selected.
The process instruction types available and the way in which you create their characteristic structure is dependent upon the control recipe destination (that is, PI sheet or external system such as a process control system) that processes that particular process instruction. Process instructions for process operators need to contain different information than process instructions for process control systems, which in turn differ depending on the functionality offered by the control system.
For more information on the type of information you can pass on to external systems and the PI sheet using process instructions, see Process Instructions .
Features
Process Instructions for External Systems
You can use the following process instruction types for external systems such as process control systems.
Type 1: Process Parameters
Type 2: Process Data Request
Type 3: Process Message Subscriptions
The following section describes one possible way of using these process instruction types to control and monitor material consumption in a specific control scenario.
In Customizing for Process Management of the standard system, you will find further examples of the process instruction categories for process control systems. The names of these instruction categories start with A .
Type 1: Process Parameters
Before production starts, the process control system needs information on the materials and the material quantities to be charged. Let us assume that this information is not defined in the process control system. In this case, it can be sent to process control in the form of process parameters. In the process order, you can use automatic assignment of characteristic values to transfer the information about the material contained in the material list to the process parameter.
Example: Process Parameter for a Process Control System
Type 2: Process Data Request or Type 3: Process Data Subscription
During production, information on the actual material quantities consumed needs to be reported to process management. In principle, this information can be requested in one of the following ways:
In a single process message subscription for all materials
In one process data request for each material
Since the control system needs information about the structure of the message to be sent, your process message subscriptions and process data calculation formulas must contain the category of the message to be sent as well as the names of the characteristics to be contained in the message.
To create the requested process messages, the process control system generally also needs information on a number of characteristic values that are only known within PP-PI:
Values such as order number and control recipe number are independent of the individual material. They can be sent in the process message subscriptions and transferred from there to the process messages.
Values such as operation/phase number or reservation item number differ between materials. This information cannot be provided in a process message subscription. You can nevertheless use a process message subscription, provided that the functionality of your process control system allows you to obtain this data from the process parameter. Otherwise, you need to create a process data request with the relevant information for each individual material.
Process Instructions for PI Sheets
One possible tool that process operators can use to carry out process instructions is the PI sheet. The following sections describe which process instruction types you can use for the PI sheet and how you must structure the process instructions.
How much you need to know about the characteristic structure of the individual process instruction types depends on the function you use to create and change your process instructions (see Manual Process Instruction Maintenance ):
If you use the process instruction assistant, you will be guided through process instruction definition by specific prompts. The characteristic structure is created by the system.
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Note that at present you cannot use the process instruction assistant to define process instructions of Type 0: Universal process instruction category.
If you maintain your process instructions in the characteristic overview, you must create the characteristic structure yourself.
In Customizing for Process Management of the standard system, you will find examples of process instruction categories of all types described here.
Detailed information about the process instruction types listed below, which you can use for PI sheet, can be found under Characteristic-Based Process Instructions for PI Sheets .