The First Scan Flag tag name is ________.

The First Scan Flag is an essential feature in programmable controller systems, particularly when initializing parameters. The First Scan Flag indicates when the controller is executing the program for the very first time since a power-up or reset. This is crucial for ensuring that specific initializations, such as setting up variables or clearing certain memory locations, occur only once at the start of the operation.

In the context of the given options, the First Scan Flag is indeed denoted as "S-FS." This naming convention follows the standard designations within many programmable controller systems, where "S" is often used to denote system-related flags or status indicators, and "FS" specifically refers to the First Scan status. Therefore, when the controller recognizes that it is in its first scan, the S-FS tag will be set to true, allowing the program to execute any first-time logic.

The other options do not correspond to this standard naming convention and would not be recognized by the system as indicating the first scan status.