FBD/ST languages

Question 1

IEC 61131-3 defines programming languages for PLCs. What are the 5 standard languages?

Answer 1

1. LD
2. FBD
3. ST
4. IL
5. SFC

Question 2

An input reference is similar to what type of instruction from LD?

Answer 2

Examine if closed (XIC)

Question 3

An output reference is similar to what type of instruction from LD?

Answer 3

OTE (output energize)

Question 4

A programmer wants to use a Boolean AND to turn on a light. How should they set up the instruction?

Answer 4

Use 2 input references and 1 output reference

Question 5

Comparison instructions in FBD are similar to LD (T/F)?

Answer 5

True

Question 6

In structured text, how is a value assigned to tags?

Answer 6

Using “:=”

Question 7

Text is colour coded in ST. What does red stand for?

Answer 7

Tags

Question 8

Text is colour coded in ST. What does blue stand for?

Answer 8

Instructions

Question 9

A programmer is using ST to make a free running timer. They enter the code and it does not run. What is the error in their code?

Answer 9

TONR (TIMER1)
TIMER1.PRE = 1000;
TIMER1.TimerEnable:=1;
TIMER1.Reset:=TIMER1.DN;