Definition of Signatures in PI Sheets 
Use
If you want to sign data in the PI sheet, you define a process data request with a signature. You have the following options:
In this case, you define the signature as part of an input validation. You only enter a signature in the PI sheet, if you want to accept an input value although it is outside the defined value range.
In this case, you add the signature as an input value into the usual sequence of steps in the PI sheet. The entries and formula results of the relevant process step are reported when the signature is entered, that is, the corresponding messages are transferred to process management for sending. After this, you cannot change the values anymore.
Technically speaking, the signature is identical to the signature that is used to sign a process step. However, it is executed at the end of the PI sheet after all process steps have been completed.
In ABAP list-based PI sheets, you can use any type of signature for this. By executing the signature, you only confirm that the data is complete and correct.
In browser-based PI sheets, you must use the
For statements concerning quality in the manufacturing process, you can enter a comment. If the corresponding Customizing settings are made, the comment is transferred to the batch record and can be used as a basis for the usage decision.
Prerequisites
The type of signature to be used in the PI sheet has been defined in Customizing for Control Recipe Destinations.
You have the following options:
You can use this type of signature for ABAP list-based PI sheets only. You define the passwords for the relevant users in Customizing for Control Recipe Destinations.
If several individual signatures are to be executed, you can also specify the following in the control recipe destination:
For more information about digital signatures and the required settings, see
Approval Using Digital Signatures.

If you want to use signatures to complete browser-based PI sheets, you must use digital signatures.
Features
Signatures for Invalid Input Values
You define these signatures if you define input validations. For more information, see:
Signature for Process Step / PI Sheet
You define these signatures as input values in a process data request. The structure rules for this process instruction are identical to that of all other data requests.
See also:
You can define one signature for each data request. Depending on the data request, the signature is processed differently.
You must assign a message category that contains characteristic PPPI_SIGNATURE to the process instruction.
Note that in repeated data requests you must enter a signature for every table line if the signature is marked as required in the message category.
You must define characteristic PPPI_SIGNATURE as an input value in the process instruction.
The characteristic is transferred to the message that the system creates for the process instruction. The following value is assigned to the characteristic:
For the following types of signature, you can specify that a user requires a special maintenance authorization for the PI sheet to execute the 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:
If several users must sign a process step, you use a

If you want to use signatures to complete browser-based PI sheets, you must use a signature strategy.
In the PI sheet, signature strategies are carried out synchronously by default. This means that all signatures must be executed immediately one after another without exiting the function.
However in process instructions that are used to sign the entire PI sheet, you can determine that the signature strategy is carried out asynchronously. The system stores the signatures individually. The PI sheet can be exited after each individual signature and can be called again by the next signatory.

If you want to use signatures to complete browser-based PI sheets, you must use the asynchronous signature process.
To define the data for the signature, you assign the following characteristics in the process instruction:
Characteristic |
Meaning |
Value |
PPPI_INPUT_REQUEST |
Input request |
Any short text |
PPPI_REQUESTED_VALUE |
Input value |
PPPI_SIGNATURE |
PPPI_SIGNATURE_ |
Required authorization |
Any value for the Activity field in the authorization object C_CRPI_BER |
PPPI_SIGNATURE_STRATEGY |
Signature strategy |
Strategy defined in Customizing |
PPPI_SIGNATURE_MODE |
Synchronous or asynchronous signature process |
S (synchronous)A (asynchronous) |