Rockwell-automation Logix5000 Controllers Add-on Instructions Programm Uživatelský manuál stáhnout pdf (Strana 30)

Chapter 1 Designing Add-On Instructions

Attribute Name Data Type Attribute Description

MajorRevision DINT Major revision number of the Add-On Instruction

MinorRevision DINT Minor revision number of the Add-On Instruction

Name String Name of the Add-On Instruction

RevisionExtendedText String Text describing the revision of the Add-On Instruction

Vendor String Vendor that created the Add-On Instruction

LastEditDate LINT Date and time stamp of the last edit to an Add-On Instruction

SignatureID DINT 32-bit instruction signature value

SafetySignatureID DINT 32-bit safety instruction signature value

For more information on using GSV and SSV instructions, refer to the Logix5000

Controllers General Instructions Reference Manual, publication 1756-RM003.

Consider the following information when you are creating parameters.

Passing arguments to parameters by reference or by value

The following information will help you understand the differences between

passing argument tags to parameters by reference or by value.

Aspect By Value (Input or Output) By Reference (InOut)

Value Synchronous—the argument's value does not change during

Add-On Instruction execution.

Asynchronous—the argument's value may change

during Add-On Instruction execution. Any access by

the instruction's logic directly reads or writes the

passed tag's value.

Performance Argument values are copied in and out of the parameters of

the Add-On Instruction. This takes more time to execute a call

to the instruction.

Parameters access argument tags directly by

reference, which leads to faster execution of

instruction calls.

Memory usage Most amount. Least amount.

Parameter data types supported Atomic (SINT, DINT, INT, REAL, BOOL). Atomic, arrays, and structures.

Considerations when

creating parameters

30 Rockwell Automation Publication 1756-PM010F-EN-P - October 2014

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Rockwell-automation Logix5000 Controllers Add-on Instructions Programm Uživatelský manuál Strana 30