Siemens SIMATIC VPU200/560 Programming Manual page 93

Description of the DEBUG Operation (continued)
8-24 Entering Ladder Programs
(RUN or ProGraM FReeZe.) This function key
RUN/PGMFRZ
F6
allows you to switch between Run and Program Freeze
modes. When "RUN" is displayed, pressing the function key
will place the system in the Run mode. This will also
disable the S.SCAN (Single SCAN) function key and enable
the PGMOFF (F7) function key. "RUN" will change to
"PGMFRZ", which indicates that pressing the function key
will place the system in Program Freeze mode. In this
mode, all outputs will cease changing and will remain in
the state they were in when the PGMFRZ function key was
pressed.
S.SCAN/PGMOFF
F7
Scan operation is only available when the system is in the
Program mode. When "S.SCAN" is displayed, pressing the
function key will cause one scan of the network program to
be performed and will change the status of the ladder logic
elements accordingly. "S.SCAN" will change to "PGMOFF"
when the RUN (F6) function key is pressed. In the Program
Off mode, discrete outputs will be set to zero and all word
outputs will be "frozen" (that is, kept in the state they were
in when the function key was pressed).
When the spacebar is pressed, one or more of the following function keys are
displayed. The particular keys displayed is determined by whether the
ladder logic program or the status chart is being displayed. Each of the keys
is described below, and the mode in which it is available is given.
(Single SCAN or ProGraM OFF.) The Single
SIMATIC VPU200/560 Programming Manual