Rockwell Automation 2711E-ND1 Reference Manual PanelBuilder 1400e - Manual (Page 109)

103 Push Buttons
Publication 2711E-6.15 – November 1998
You can adjust the size of the Normally Closed Momentary Push
Button and format its foreground color, background color, button
margins (touch screen applications only), border style, fill style, and
blink attributes. For details on formatting objects see “Changing
Object Appearance” in Chapter 9, Creating Objects, in the
PanelBuilder 1400e Configuration Software for Windows User
Manual.
A Latched Push Button changes state when pressed and remains in
the latched state until unlatched by the PLC. This button uses a
Handshake control as well as the Button Control and Indicator State
control.
Pressing the button sets the Button Control to the state 1 value.
When this happens, the PLC program must set the Handshake
control to a non-0 value. When the terminal detects that the
Handshake control has made a 0 to non-0 state transition, it resets the
Button Control to the state 0 value. Your PLC must be programmed
to set the Handshake control back to 0.
If the Button Control cannot accommodate the state value (if the
value is too large for the control’s address), an error message is
displayed, and the PLC value is not changed. The operator must
clear the fault before continuing.
Use the Latched Push Button when you want the Button Control to
remain on until a particular process within the PLC is completed.
Tip: Use a Latched Push Button if you have a PLC with long
program or I/O scan times. Use the Handshake control to signal that
the program has read the Button Control. You can accomplish the
same thing by creating a Normally Open Momentary Push Button
with a long enough Push Button Hold Time, but a Latched Push
Button takes the guesswork out of estimating the program or I/O
scan times, or the network responsiveness in DH+ and ControlNet
applications.
Note: If the Indicator State value does not match any of the defined
state values, an error state occurs and the button displays state 1
without labels. An error state also occurs if the Button Control is not
assigned. In this case also, the button displays state 1 without labels.
Important: The Latched Push Button does not retain its value when
power is switched off and on again, after screen
changes, or when the terminal is switched to
Configuration mode and then back to Run mode. The
Button Control is reset to the initial state value.
Latched Push Button
"
"