Overview

Question 1

What are the five parts of IEC 61131 standard for programmable controllers?

Answer 1

Part 1: General overview information
Part 2: hardware requirements
Part 3: programming language
Part 4: user guidelines
Part 5: communication

Question 2

The languages consists of two textual and three graphical, define them

Answer 2

Textual:
Instruction list
Structured test

Graphical:
Ladder program
Function block diagram
Sequential function chart

Question 3

The choice of programming languages depends on (4)

Answer 3

Programmers background
Problem at hand
Structure of the control system
Interface to other people

Question 4

Benefits of structured text (6)

Answer 4

PowerText facilitates system debugging and application commissioning
2. People trained in computer language can easily program control logic
3. Symbols makes the program easy to understand
4. Program can be created in any text editor
5. Runs as fast as ladder logic
6. Good for complex calculations

Question 5

Benefits of function blocks (2)

Answer 5

1. Graphical
2. Hierarchical through elementary and derived function blocks

Question 6

Benefits of instruction lest:2)

Answer 6

1. Text based Boolean
2. Supports jumps

Question 7

Explain instruction list language

Answer 7

Assembler type Low level language. For small applications and optimizing parts, useful in cases where small functions are repeated often. Difficult to learn.

Question 8

Explain structured text language

Answer 8

New language cause high level syntax needed
Resembles pascal or basic
Used forcomplex math,algorithms, decision making. Allows large algorithm to be displayed on a single page

Question 9

Explain function blocks language

Answer 9

Very common. Allows programs in other languages to be nested within the FBD.
Elements appear as blocks wired together resembling a circuit diagram. Suited for representing batch control applications.
Applications involving high degree of information/ data flow between control components such as process control

Question 10

Explain Sequential flow chart

Answer 10

Used to organize the program flow into sequence of steps and transitions.
The actual control programming must still be done in other language, it gives an overview of the system and help combine the expertise of people with different background.

helps to decompose a control problem into manageable
parts, while maintaining the overview.

Question 11

Sequential function chart consists of

Answer 11

Consists of steps linked with action blocks and transitions.
Each step represents a particular state of the system being controlled,
Transition is associated with a system being controlled. Transition is associated with a condition, when true deactivates the step before transition and activates the step after. Steps are linked to action blocks, performing a
certain control action. Each element can be programmed
in
any of the IEC languages, including SFC itself. You can use
alternative sequences and even parallel sequences, such
as commonly required in batch applications.