Generate the Instruction Signature

The instruction signature consists of an ID number and time stamp that identifies the contents of the Add-On Instruction at a given point in time. The source of the date and time is from the local clock on the computer generating the signature.

The instruction signature enables you to quickly determine if the instruction has been modified. Each Add-On Instruction can have its own signature. The instruction signature is required when an Add-On Instruction is used in safety-related functions, and can sometimes be required for regulated industries. Use it when your application calls for a higher level of integrity.

Once generated, the instruction signature seals the Add-On Instruction, which helps prevent it from being edited while the signature is in place. This restriction includes rung comments, tag descriptions, and any instruction documentation that was created. When the instruction is sealed, you can perform only these actions:

When you generate an instruction signature, the

Studio 5000 Logix Designer®

application displays the instruction definition with the seal icon.

When you generate a safety signature for a controller project, the Quick View Pane and Safety Signature Report show a safety signature element for Add-On Instructions even if the instruction signature is not generated. For more information about safety signature elements, see Safety Signature.

When a sealed safety Add-On Instruction is downloaded for the first time, a safety instruction signature is automatically generated.