1. EPOS Programming Terms Programming Tool: Projects
Basics of the PLC Programming
Programming Language IEC Standard
Sample Programs
EPOS P Training

2. Description of some terms
PLC Programmable Logic Control
PLCopen An Industrial Control organisation
IEC Programming Standard created by
PLCopen (in the past IEC 1131)
OpenPCS Programming tool for EPOS P
(from Infoteam)

3. What is a PLC? PLC roots in the wiring logic
outputs
actuators
motors, valves
inputs
sensors
PLC
roots in the wiring logic
originally hardware based: Relays
increasingly software based
more flexible, easier to modify
more efficient, lower costs
needs a programming device
industrial PC = PLC + programming device
programming device will be removed after programming
special requirements: rough environment
no moving parts such as harddisks

4. A PLC program works in a cyclic manner
Cyclic calculation of the output pattern according to the input pattern
it starts again when it’s finished
no inputs during the cycle
cycle time depends on the application
smart living technology: < min;
drives: several ms
particular programming languages
inputs
program
inputs
cycle time
outputs

5. What is PLCopen? User organisation for the promotion of
IEC standards
develops and publishes the standards (e.g. for Motion Control, Safety, …)
certification authority
PLCopen and maxon EPOS P
motion functionality based on PLCopen Motion Control
The use of the PLCopen Logo is expensive; therefore we do not advertise with it!

6. What is IEC ?
describes concepts and directives for building a PLC project, respectively PLC program
use of defined terms (key words)
contains 5 equal programming languages
drive/motion function library
advantages
widely spread in the PLC world and motion control industry
well known “look and feel”, no need to learn new language
independent of used hardware
“a certain” re-usability of PLC programs
widely accepted

7. OpenPCS the programming tool for the EPOS P
from company: Infoteam
follows the standard IEC
not described in the IEC standard:
How does a program editor have to look?
management of projects and libraries
documentation
online functions, e.g. software modification, debugging
file and data base structures
and this is where the programming tools differ!

8. Configuration PLC configuration in general Project in the EPOS-Studio
Project in the OpenPCS

9. Project in the EPOS Studio
describes involved components and its communication
EPOS P: for 1 EPOS P
EPOS: for 1 EPOS
MCD EPOS: for 1 MCD EPOS
MCD EPOS P: for 1 MCDEPOS P
For Network: Create New Project
Info will be handed over to OpenPCS
tools and wizards depend on involved components
communication, network connections

10. e.g. EPOS Project
for a EPOS
navigation is adjusted

11. OpenPCS Project project contains resource = processing unit of the PLC
resources, runtime programs
allocation of variables to physical PLC addresses
references to other programs: global variables, data types
corresponds to PLC configuration
resource = processing unit of the PLC
e.g.: EPOS P “master function", CPU’s, special processors
on one resource several runtime programs can run
program sequence controlled by "Task"
importance = priority
execution type: periodic, cyclic, interrupt

12. Programming POU Program Organisation Unit
Programs, Function Blocks, Functions
Variables declaration, types
Programming languages

13. Program Organisation Unit (POU)
For structuring IEC application programs
3 types of POU
Functions (FUN)
Function Blocks (FB)
Programs (PROG)
PROG FB
FUN FB
FUN
FUN
FUN
FUN
POU’ s have a strict hierarchy
recursion is not allowed
memory demand is known from the beginning
memory allocation can be made

14. Program Organisation Unit (POU)
FUNCTION
structure of a POU
begin and end with KEY WORD (taken care of by OpenPCS)
declaration section
interface variables, local variables
instruction section in one of the 5 programming languages
FUNCTION_BLOCK
PROGRAM
Interface
variables
local Variables
Instruction
POU body
END_PROGRAMM
END_FUNCTION_BLOCK
END_FUNCTION

15. Characteristics of POU‘s
closed unit
can be compiled independently
can be called within the whole project
can be used in the whole project
unique name within a project
new POU
File -> New -> POU
libraries can be built of FUN’s and FB’s
reusability and modularisation
e.g.: standard library, MC library, CAN library

16. POU – variable declaration
VAR local data
VAR_INPUT input parameter
VAR_OUTPUT output parameter
VAR_INOUT input and output
VAR_GLOBAL global data
VAR_EXTERNAL reference to
global data
END_VAR key word
for the end

17. POU – type declaration for each variable a type has to be defined
optionally an initial value can be specified
else standard value
or value of previous call
types can also be defined by the programmer
File -> New -> Declarations ->Types
global valid
TYPE … END_TYPE

18. Variable declaration in OpenPCS
VAR_GLOBAL
global data of the resource
File -> New -> Declarations -> Global
global data of the program
upper panel of the program
all other VAR
upper panel of the POU

19. Functions (FUN) return exactly one output value without memory
call with input variable (VAR_INPUT)
for the same input, there is always the same output value
without memory
only local variables allowed (VAR), which will be initialised at every call
no global or external variables allowed
FUN can only call other functions
standard functions are predefined
arithmetic functions and comparisons
e.g. sin (x)
FUNCTION Hallo: BOOL
VAR …
END_VAR
Hallo := TRUE
END_FUNCTION

20. Function Blocks (FB) work with an own data record
with memory for internal state
instantiation
output depends on the inputs and state information
input parameter and output parameter
can call FUN’s and other FB’s
predefined standard FB’s
e.g. for timer and counter
predefined Motion Control FB’s
e.g. for relative movements

21. Program (PROG) main program defines the access to the PLC periphery
“brain" of an PLC application program
There is only one instance
defines the access to the PLC periphery
allocation to the physical address (e.g. input and output of the PLC)
declaration of the variables of the whole program (VAR_GLOBAL)
has no input and output parameter

22. Programming languages in IEC 61131-3
5 equivalent programming languages
IL: Instruction List similar to assembler
ST: Structured Text similar to high level programming language
LD: Ladder Diagram graphical
FBD: Functional Block Diagram graphical
SFC: Sequential Function Chart graphical
It doesn’t matter with which language the user writes his program. It is even possible to write different parts (POU’s) of the program in different languages.
IL Textual, line oriented, efficient, close to machine code
ST High level language, for complex problems, similar to PASCAL
LD Widely used diagram format, intuitive use of boolean functions, function blocks
FDB Use of predefined functionality, graphical programming tool
SFC Graphical programming tool, sequental and parallel processes, for complex structures, state machines

23. FBD Function Block Diagram
graphical, strong accentuation of the function blocks and the functions
Similar to LabView
relatively big overhead for parameters and FB
no conditional code programmable (all FB will always be loaded and called)
realistic cycle times >= 10 ms
30 IL/ms)

24. Sample FBD: SimpleMotionSequence
FUNCTION_BLOCK
with instantiation
FUNCTION
without name
variables, constants,
virtual connections

25. Libraries standard library motion control (MC) library CANopen library
for timer functions, arithmetical functions, …
see OpenPCS help
motion control (MC) library
for axis control
according to PLCopen standard
see Programming Reference 6.1
CANopen library
for reading and writing of SDO objects
according to CANopen Standard
see Programming Reference 6.2

26. LD / LDD Ladder Diagram graphical widely used in USA and Asia
in the style of current logic, relay technique
Boolean logic
widely used in USA and Asia
Rockwell LD-Editor as reference

27. SFC Sequential Function Chart
graphical
for process control engineering
steps: will be executed if activated
conditions (transitions)
will be executed after the previous step is finished
deactivates previous step and activates next step

28. IL Instruction List widely used in Europe
VAR
First, Second, Result: INT:=10;
StringOp: String[30]:=' ';
StringRes: String[25]
END_VAR …
B1: LD First (* 10(INT) *)
ADD Second (* 20(INT) *)
ST Result (* 20(INT) *)
GT 0 (* True(BOOL) *)
JMPC B2 (* because
CR=True *)
JMC FarAway (* CR undefined, reaction depends
on implement.*)
B2: LD StringOp (*
(String) *)
ST StringRes (* *)
widely used in Europe
textual programming similar to assembler
PLC assembler
line oriented
1 line = 1 instruction
CR = current result
the virtual accumulator for all data types
realistic cycle times:
optimised down to 1 ms

29. ST Structured Text widely used in Europe
textual, similar to high level language (e.g. Pascal or C+)
some features
instructions separated with “ ; ”
loops: FOR, WHILE, REPEAT
conditions: CASE, IF…THEN…ELSIF...ELSE
complex expressions
realistic cycle times:
optimised down to 1 ms

31. Exercise 1:
Download SimpleMotionSequence Program to the controller and execute it.

32. Exercise 1a:
Create a program that will enable the drive and move the motor to an absolute position.
Position = 20000
Velocity = 1000
Acceleration = 10000
Deceleration = 10000

33. Exercise 1b:
Create a program that will oscillate the motor between two positions using FBD.
Position 1 = 0
Position 2 = 20000
Velocity = 1500
Acceleration = 15000
Deceleration = 15000

34. Exercise 1 continued… Step 2: Click on Open Programming Tool
Step 4: Select maxon motor ag
Step 5: Select EPOS P Project
Step 6: Enter Project Name
Step 7: Click OK
Step 8: Click on File  New
Step 1: Double Click on “IEC Programming”
Step 9: Select FBD
Step 10: Verify POU-Type is Program
Step 11: Enter POU Name
Step 12: Click OK
Step 3: Click on File Project  New
Step 13: Click Yes to add to Active Resource