Electronic Signatures can be applied either broadly on a system-wide basis or selectively on an area-by-area, module-by-module basis to facilitate granular configuration, testing, and commissioning. Polices can be assigned to modules at configuration time and temporarily disabled on an area or the entire system during testing or when signatures are not required. Then when the configuration is ready for normal operation, Electronic Signatures can be enabled at the level of granularity required for your situation.
Each module can have only one policy assigned to it; however, there is no limit to the number of signature policies allowed in the database.
Carefully consider the use of slew buttons in operator graphics. Slew buttons are used to gradually increase or decrease a value and can be difficult to use on parameters that are subject to Electronic Signatures since each click on a slew button is a separate parameter write.
To assign a policy to a non-class-based module or module template, select Electronic Signature from the module's context menu and browse to the policy.
Disabling Signature Policies in the System Properties dialog does not disable electronic signatures on modules. To disable electronic signatures on modules you must remove the signature policy on each module before disabling Signature Policies on the System Properties dialog.
Once a policy is assigned to a module and the module is downloaded, signatures will be required for writes to the module parameters specified in the policy.
In addition to modules made directly in an area or from a module template, electronic signature policies can be assigned to the following types of classes:
Signature policies cannot be assigned to process cell classes.
If you change the Signature Policy on a reference to a Phase Class under a Unit Class, the change is made on the Phase Class itself and propagates to all references to the Phase Class under the Unit Class.