Rockwell Automation AutoMax Enhanced Ladder Language Reference Manual - Manual (Page 22)

1Ć6
1.5 Using Transition Contacts
This section explains the methods for using transition contacts PTI and NTI and how
the transitions will be interpreted. The methods explained in this section are the
following:
D using a variable only on a transition contact
D using a variable on a coil and on a transition contact
D using a variable on more than one coil and on a transition contact
D forcing or setting variables used on transition contacts
D using a variable on a set (SCO) coil and reset coil (RCO) pair and on a transition
contact
D using transition contacts in a program with a Jump and Label construct
1.5.1 Using a Variable Only on a Transition Contact
When you use a variable only on transition contacts and not on any other coil within a
program, the transition contact behaves as follows:
D If the variable is local, setting or forcing the variable causes the transition contact to
always evaluate true. Therefore always use a coil for the local variable somewhere
else in the program.
D If the variable is global, another task determines whether a transition is detected by
the transition contact, since only another task can change the variable's value.