Alias Tags - PLC Programming & Automation

Alias Tags in Studio 5000: When They Help and When They Hide the Problem

A tag editor view with three alias rows and the base tags they point at, and the copy of one of them made by a MOV in a different routine

What a Studio 5000 alias tag shares with its base, how it changes a force and a cross reference, and the tag scheme an alias cannot fix on a 1756-IB16.

Cross-Referencing a Tag in Studio 5000 to Find Every Rung That Writes It

by PLC

A cross reference listing for one output tag, showing which routine each reference sits in, which instruction holds it, and whether that reference changes the tag or only examines it

Find every instruction that writes a tag in Studio 5000, tell a write from a read, and work out why an output with two writers flickers on a 1756-OB16D.

Forcing an Input on a ControlLogix, and Being Certain You Removed It

by PLC

The three FORCE indicator states on a ControlLogix 5580 controller with what each one says about installed force values and the controller-level enable

Install a force on a 1756-L83E, enable it, then prove it is gone: the three FORCE indicator states, the GSV that reads force status, Remove vs Disable.