RLL
P
LUS
Stage
Programming
7--2
RLL
PLUS
Stage Programming
DL105 PLC User Manual, 3rd Edition
Introduction to Stage Programming
Stage Programming provides a way to organize and program complex applications
with relative ease, when compared to purely relay ladder logic (RLL) solutions.
Stage programming does not replace or negate the use of traditional boolean ladder
programming. This is why Stage Programming is also called RLL
PLUS
. You won’t
have to discard any training or experience you already have. Stage programming
simply allows you to divide and organize a RLL program into groups of ladder
instructions called stages. This allows quicker and more intuitive ladder program
development than traditional RLL alone provides.
Many PLC programmers in the industry
have become comfortable using RLL for
every PLC program they write... but often
remain skeptical or even fearful of learning
new
techniques
such
as
stage
programming. While RLL is great at
solving boolean logic relationships, it has
disadvantages as well:
S
Large programs can become almost
unmanageable, because of a lack of
structure.
S
In RLL, latches must be tediously
created from self-latching relays.
S
When a process gets stuck, it is
difficult to find the rung where the
error occurred.
S
Programs become difficult to modify
later, because they do not intuitively
resemble the application problem
they are solving.
STAGE!
Y2
X3
OUT
X0
RST
C0
X4
SET
Y0
C1
It’s easy to see that these inefficiencies consume a lot of additional time, and time is
money.
Stage programming overcomes these obstacles!
We believe a few
moments of studying the stage concept is one of the greatest investments in
programming speed and efficiency a PLC programmer can make!
So, we encourage you to study stage programming and add it to your “toolbox” of
programming techniques. This chapter is designed as a self-paced tutorial on stage
programming. For best results:
S
Start at the beginning and do not skip over any sections.
S
Study each stage programming concept by working through each
example. The examples build progressively on each other.
S
Read the stage Questions and Answers at the end of the chapter for a
quick review.
Overcoming
“Stage Fright”
Summary of Contents for DL105
Page 2: ...DL105 PLC User Manual Manual Number D1 USER M...
Page 308: ...1B DL105 Error Codes In This Appendix Error Code Table...
Page 314: ...1C Instruction Execution Times In This Appendix Introduction Instruction Execution Times...
Page 324: ...1D Special Relays In This Appendix DL105 PLC Special Relays...
Page 327: ...1E PLC Memory In This Appendix DL105 PLC Memory...