Allen-Bradley 1756-L65 ControlLogix 5565, Programming Manual

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Rockwell Automation Publication 1756-PM004D-EN-P - September 2012 81
Data Access Control Chapter 4
Constant Checkbox Availability
The state of the Constant checkbox depends on a number of conditions.
Dialog Box/Window Considerations
New Tag The Constant box is disabled if:
• the tag is an alias tag.
• the Factory Talk Security action is not enabled for changing constant value
property of a tag.
• you do not have permission to modify tag properties
(Factory Talk Security Tag Modify is denied.)
• the new tag is a Consumed tag.
• the tag’s Data Type is not a data table-backed type.
• the tag’s Usage setting is not ‘InOut’.
• redundancy controller is in any state that does not
allow changes.
• the controller is safety-secured and the tag is a safety tag.
(1)
• if the Scope is an equipment phase and the equipment phase feature is not
activated in the current license.
• the controller is in hard-run mode.
• the Add-On Instruction is in Source Protection mode.
(1)
If the controller is in safety-locked mode, only the safety tags will be disabled from being accessed, the standard tags will have the
same behavior as in the unlocked mode. The Constant value box will be disabled in the Tag Properties dialog box only if the tag is a
safety tag.
Tag Properties
Same considerations apply as for New Tag above.
Tag Editor
Tag Monitor The value of a constant tag can be modified by using the Tag Monitor window if you
have both standard Tag: Modify Values permission and Tag: Modify Constant Tag
Values permission. You cannot modify a constant value in any of the language editors
or any other tag browser. The icon
in the Value column indicates that you are
changing a constant value tag’s value. Any modifications to the values of constant
tags are recorded in the Controller Log for future reference.
For controller logging, see the
Logix5000 Controllers Information and Status
Programming Manual , publication 1756-PM015 .