Rockwell Automation 2706-MB1 MESSAGEVIEW 421 SOFTWARE MANUAL - Manual (Page 17)

1–7 Introducing MessageBuilder Configuration Software
Publication 2706-817
Function Keys
MessageView 421F terminals can use applications that have
Function keys enabled. An enabled function key is assigned to one of
these types:
A Momentary Function Key changes state when pressed and
changes back to the original state when its hold time has expired
after it is released.
A Maintained Function Key changes state when pressed and
remains in the changed state when released. It changes back to the
original state when the Function Key is pressed and released again.
A Latched Function Key changes state when pressed and remains
in that state until the controller unlatches it.
!
ATTENTION: Function Keys are active only when
they are enabled for a message currently displayed by
the terminal. All other Function Keys are non-active.
Example
Suppose a message has function keys F1, F5, and F9 enabled.
Whenever that message is displayed by the MessageView terminal,
these three keys are activated, but the 13 other Function keys remain
inactive.
When the message is terminated, the three Function keys are
inactivated at once.
Note: A Latched Function key remains in its changed state until the
controller unlatches it, but it is not active after its message is
terminated.