1. TASK 1 UZ D tD w1 w2 C tC G1 G2 B tB A w3 tA TK E
Problem: Contact thermometer gives information about temperature.
It sends four signals A, B, C, D to the control system. When the temperature t is bigger or equal tA – thermometer sends „1” as signal A. When t< tA – thermometer sends „0”. It is similarly for temperatures: tB, tC, tD and signals B, C, D.
Design the system which control contacts W1, W2 and W3 according to program below [table 1]: TK E

2. TABLE 1 t < tA tA≤ t < tB tB≤ t < tC tC≤ t < tD t ≥ tD
Temperature
Comment
t < tA
Electric heaters G1 and G2 work in parallel
running mode.
tA≤ t < tB
Electric heater G1work.
tB≤ t < tC
Electric heater G2 work.
tC≤ t < tD
Electric heaters G1 and G2 work in serial running mode.
t ≥ tD
Electric heaters G1 and G2 don’t work.

3. WHEN t < tA UZ W1=1 W2=1 W3=0 G1 G2 D tD C tC B tB A tA E
A B C D W1 W2 W3 Comment
t < tA E
Electric heaters G1 and G2 work
in parallel running mode

4. WHEN tA <= t < tB W1=1 W2=0 W3=0 G1 G2 UZ E A B C D tD tC tB tA
A B C D W1 W2 W3 Comment
tA <= t < tB
Electric fire G1 works.

5. WHEN tB <= t < tC W1=0 W2=1 W3=0 G1 G2 UZ E A B C D tD tC tB tA
A B C D W1 W2 W3 Comment
tB <= t < tC
Electric heater G2 works.

6. WHEN tC <= t < tD W1=0 W2=1 W3=1 G1 G2 UZ E A B C D tD tC tB tA
A B C D W1 W2 W3 Comment
tC <= t < tD
Electric heaters G1 and G2 work in serial running mode

7. WHEN t >= tD W1=0 W2=0 W3=1or W3=0 G1 G2 UZ E A B C D tD tC tB tA
A B C D W1 W2 W3 Comment
t >tD
Electric fires G1 and G2 don’t work.

8. TRUE TABLE INPUTS OUTPUTS A B C D W1 W2 W3 1 t < tA tA<=t<tB1
t < tA
tA<=t<tB
tB<=t<tC
tC<=t<tD -
t >= tD

9. FUNCTION EQUATIONS FOR OUTPUT W1
INPUTS
OUTPUTS A B C D W1 W2 W3 1
t < tA
tA<=t<tB
tB<=t<tC
tC<=t<tD -
t >= tD
W1 = A * B * C * D + A * B * C * D

10. FUNCTION EQUATIONS FOR OUTPUT W2
INPUTS
OUTPUTS A B C D W1 W2 W3 1
t < tA
tA<=t<tB
tB<=t<tC
tC<=t<tD -
t >= tD
W2 = A * B * C * D + A * B * C * D + A * B * C * D

11. FUNCTION EQUATIONS FOR OUTPUT W3
INPUTS
OUTPUTS A B C D W1 W2 W3 1
t < tA
tA<=t<tB
tB<=t<tC
tC<=t<tD -
t >= tD
W3 = A * B * C * D

12. KARNAUGH TABLE FOR OUTPUT W1
C D
0 0
0 1
1 1
1 0 1 -
W1 = B

13. KARNAUGH TABLE FOR OUTPUT W2
C D
0 0
0 1
1 1
1 0 1 -
W2 = A + B * D

14. KARNAUGH TABLE FOR OUTPUT W3
C D
0 0
0 1
1 1
1 0 - 1
W3 = C * D

15. EQUATIONS FOR OUTPUTS W1, W2 and W3
W1 =B
W2 =A + B * D
W3 = C * D

16. LOGIC CIRCUITS
A B C D 1
& W3
>=1 W1 W2

17. TABLE 1 t < tA tA≤ t < tB tB≤ t < tC tC≤ t < tD t ≥ tD
Temperature
Comment
t < tA
Electric heaters G1 and G2 work in parallel
running mode.
tA≤ t < tB
Electric heater G1work.
tB≤ t < tC
Electric heater G2 work.
tC≤ t < tD
Electric heaters G1 and G2 work in serial running mode.
t ≥ tD
Electric heaters G1 and G2 don’t work.

18. TASK 1 ON PLC No Name of element Identifier Address PLC Comment 1
Sensor of temperature tA A I1
Input signal 2
Sensor of temperature tB B I2 3
Sensor of temperature tC C I3 4
Sensor of temperature tD D I4 5
Control contact W1 Q1
Output signal 6 W2 Q2 7 W3 Q3

19. TASK 1 ON PLC A B C D PROGRAM PLC Function Block Diagram (FBD)
I1 I2 I3 I4 I5 I6 I7 I8 I9 I10 I11 I12
Q Q Q3 Q4 Q5 Q6 Q7 Q8
PROGRAM PLC
Function Block Diagram (FBD)

20. LOGIC CIRCUITS
I1 I2 I3 I4 1
& Q3
>=1 Q1 Q2

21. TASK 1A w1 w2 w3 UZ G1 G2 E A B C D tD tC tB tA
A B C D W1 W2 W3 Comment
tB <= t < tC
In this case short circuit appears.

22. NEW KARNAUGH TABLE FOR OUTPUT W1
C D
0 0
0 1
1 1
1 0 1
W1 = B * C * D

23. NEW KARNAUGH TABLE FOR OUTPUT W2
C D
0 0
0 1
1 1
1 0 1
W2 = A * B * C * D + A * B * D

24. NEW KARNAUGH TABLE FOR OUTPUT W3
C D
0 0
0 1
1 1
1 0 1
W3 = A * B * C * D

25. New logic circuit
A B C D 1
& W3 W1 W2
>=1

26. TASK 1A ON PLC No Name of element Identifier Address PLC Comment 1
Temperature sensor (tA) A I1
Input signal 2
Temperature sensor (tB) B I2 3
Temperature sensor (tC) C I3 4
Temperature sensor (tD) D I4 5
Control contact W1 Q1
Output signal 6 W2 Q2 7 W3 Q3

27. TASK 1A ON PLC A B C D PROGRAM 1a PLC Function Block Diagram (FBD)
I1 I2 I3 I4 I5 I6 I7 I8 I9 I10 I11 I12
Q Q Q3 Q4 Q5 Q6 Q7 Q8
PROGRAM 1a PLC
Function Block Diagram (FBD)

28. New logic circuit
I1 I2 I3 I4 1
& Q3 Q1 Q2
>=1

29. THANKS FOR ATTENTION