Type 0: Definition of Input Validations 
Use
When defining characteristics in Customizing, you can specify an allowed value range for each characteristic. The settings you make here apply to all process instructions and messages in which the characteristic is used.
If you want to restrict the value range even further for a specific input value, you can define an input validation for it in the process instruction. In the input validation, you determine:
Prerequisites
If you want to use a check function to check the input value, a suitable function module must have been created in the system.
To create or display function modules, go to Customizing for Process Management and choose Process Instructions -> Define PI Categories for R/3 PI Sheet Using Characteristic Overview -> Assign Characteristics to Dynamic Function Calls ->
Create Function Modules for Dynamic Function Calls.
If a signature must be entered to accept invalid input values in the PI sheet, you must specify in Customizing for Control Recipe Destinations which type of signature you want to use in the PI sheet. You have the following options:
If several individual signatures are to be executed, you also specify the
signature strategy in the control recipe destination.For more information about digital signatures and the required settings, see
Approval Using Digital Signatures.You can define Signatures without a password check in cockpits. Digital signatures may not be used.
Activities
Validation Rule
In the process instruction, you can define the validation rule for the input validation as follows:
Characteristic |
Meaning |
Value |
PPPI_VALIDATION_FORMULA |
Check formula (max. 8 times) |
Boolean formula |
Characteristic |
Meaning |
Value |
PPPI_VALIDATION_FUNCTION |
Check function |
Function module name |
You must include the parameters of the function module in the process instruction directly after the characteristic for the check function. For more information, see
Processing Invalid Input Values
In addition to the validation rule, you can also enter the following information to control how invalid input values are processed:
Depending on the settings made in the control recipe destination, the PI sheet requests a signature without a password, one digital signature, or several individual signatures defined in a signature strategy. In cockpits, you may only use signatures without a password. You must also enter a comment for digital signatures.
The input value is not reported automatically when the signature is executed. Once you have entered a correct value again, the system automatically accepts this value, which means you do not need to execute another signature.
The system then checks if the activity specified in the process instruction has been included in authorization object C_CRPI_BER in the user master record.

Irrespective of the settings you make here, the system checks the following authorizations for digital signatures:
Activities
To enter this data in the process instruction, you assign the following characteristics immediately after the validation rule:
Characteristic |
Meaning |
Value |
PPPI_TEXT_FOR_INVALID_INPUT |
Warning |
Long text (see also Using Text Symbols) |
PPPI_ACCEPT_INVALID_INPUT |
Invalid values are accepted |
No Yes With signature only |
PPPI_SIGNATURE_AUTHORIZATION |
Authorization required for signature without a password or digital signature |
Any value for the Activity field in the authorization object C_CRPI_BER |
In PI sheets only: |
Signature strategy |
Strategy defined in Customizing |