Rockwell-automation Logix5000 Controllers I/O and Tag Data Programming Instrukcja Użytkownika Pobierz pdf (Strona 76)

Chapter 4 Data access control

Only tags with external access settings of Read/Write or Read Only can be

mapped to a PLC-2 controller and PLC-5/SLC controllers.

1. In the PLC-2 or PLC-5/SLC Mapping dialog box, type a file number.

2. Choose a tag from the Name list. Only eligible tags that are set to either

Read/Write or Read Only appear in the menu.

If you manually type the name of a tag whose external access is set to None,

an error message appears.

3. Click OK.

The Logix Designer application preforms a check to verify an imported program

file has a valid external access value. A default value is assigned to unspecified tags

that are imported from programs created in the Logix Designer application earlier

than version 18.

An error message appears in the Logix Designer application for imported files that

contain tags with any value other than Read/Write, Read Only, and None.

Object Name Default External Access

Controller and program-scoped standard tags Read/Write

All safety tags( Read Only

Add-on Instruction local tags Read/Write

Add-on Instruction Input parameters Read/Write

Add-on Instruction Output, EnableIn and EnableOut parameters Read Only

Add-on Instruction InOut parameters N/A

Equipment phase output parameters Read Only

Members of all data types Read/Write

In version 18 and later of the Logix Designer application, you can designate tags as

constants to protect them from being changed programmatically by:

• The controller programming application.

• Logic in the controller.

The tags that you cannot designate as constants are User-defined type members,

Add-On Instruction input and output parameters, and local tags. You make a tag a

constant value tag by selecting the Constant check box on tag creation dialog

boxes and tag editor/monitor windows.

Tag mapping

considerations

Imported tag behavior

Constant value tags

76 Rockwell Automation Publication 1756-PM004E-EN-P - October 2014

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Rockwell-automation Logix5000 Controllers I/O and Tag Data Programming Instrukcja Użytkownika Strona 76