Chapter 15 - Sequencers

1. You can use register N7:0 as a control register in a sequencer output (SQO) instruction. T/F

F

2. The normally open contact R6:0/DN will close whenever the sequencer output (SQO) instruction is enabled. T/F

F

3. The normally open contact R6:0/FD will close whenever the sequencer compare (SQC) instruction is enabled. T/F

F

4. File B3 may be used to hold the sequencer output (SQO) instruction’s patterns. T/F

T

5. The length parameter specifies the number of words in the sequencer file. T/F

F

6. You can step two or more sequencer instructions simultaneously. T/F

T

7. You must use the reset (RES) instruction to reset the SQO instruction’s position to zero. T/F

T

8. The .LEN and .POS can hold numbers up to 256 since an SQO can have up to 256 steps. T/F

T

9. There are 255 sixteen-bit words in file B3. T/F

F

10. There are 255 sixteen-bit words in file B10. T/F

F

11. The ______________________________ instruction transfers data from the sequencer source file to the

output destination module.

SQO

12. The ______________________________ instruction is used to control several outputs with multiple step

patterns.

sequencer

13. PLC manufacturers use the ______________________________ instruction instead of the sequencer

instruction.

table-to-reg/file-to-word

14. The normally open ______________________________ input must be closed to energize the sequencer

instruction.

enable

15. A low-to-high pulse on the ______________________________ input causes the sequencer to advance to the

next output pattern.

step

16. When the normally open ______________________________ input is closed, the sequencer instruction

resets to the first output pattern.

reset

17. The number of ______________________________ indicates the number of data patterns the sequencer

instruction must step through.

steps

18. The ______________________________ register holds the first data pattern.

starting

19. The ______________________________ register points to the step that the instruction is on.

step pointer

20. The ______________________________ register is an output group register that indicates the output

terminals on which data is placed.

destination

21. The ______________________________ parameter in the sequencer block holds the total number of steps

that must be completed before the sequencer done status bit (R6:0/DN) coil is energized.

sequencer length

22. The ______________________________ parameter indicates the step that is desired to start the sequencer

instruction.

sequencer position

23. The ______________________________ instruction reads input data from an input module or register and

then compares the input data to the step patterns in a bit data file (B3 or B10) or integer data file (N7).

SQC

24. The ______________________________ instruction is used to read the PLC input module and store the input

data in a file.

SQL

25. The number of sequencer steps can be increased by connecting two sequencers in series, which is called

______________________________ sequencers.

cascading

26. The number of outputs that are controlled by the sequencer system can be increased by connecting sequencers

in ______________________________.

parallel

27. Name the three types of sequencer instructions of an Allen-Bradley SLC 500 series PLC.

SQC,SQL,SQO

28. Name the control registers used by sequencer functions SQO, SQL, and SQC.

R6:0, R6:255,

29. How do you reset a sequencer function?

RES

30. Name the data files that can be used for the source in a sequencer output (SQO) instruction.

B3, B10 and N7

1. The sequencer instruction is also referred to as the ____ instruction.

A. data transfer

B. drum sequencer

C. register to table

D. All of the above.

B

2. In the following SQO instruction block, which parameter holds the starting address?

A. File

B. Source

C. Position

D. Mask

C

3. In the following SQO instruction block, which parameter is used to hide some of the bit patterns?

A. File

B. Source

C. Position

D. Mask

D

4. In the following SQO instruction block, which parameter holds the address of the output port?

A. File

B. Source

C. Position

D. Destination

D

5. In the following SQC instruction block, which parameter holds the address of the input port?

A. File

B. Source

C. Position

D. Destination

B

6. Which status bit indicates whether the data on the input port matches the data stored in the sequencer data

file?

A. DN

B. FD

C. EN

D. ER

B

7. In the following drum sequencer, the bit pattern for Step 5 is ____.

A. 0000 0001

B. 0100 0000

C. 1001 0000

D. 0100 1010

C

8. In PLC applications where the sequencer needs to control more than 16 ports, the sequencers are connected

____.

A. simultaneously

B. in series

C. in parallel

D. in a cascading arrangement

C

9. In the following SQL instruction block, which parameter holds the data table?

A. File

B. Source

C. Position

D. Length

A

10. The following figure displays the operation of the ____.

A. SQO instruction

B. SQL instruction

C. SQC instruction

D. All of the above.

B

11. For the SQO instruction’s operation in the following image, which outputs are energized in Step 5?

A. 0:2/0 and 0:2/3

B. 0:2/15 and 0:2/3

C. 0:2/16 and 0:2/4

D. 0:2/15 and 0:2/4

B

12. What sequencer instruction does the following schematic diagram represent?

A. SQO

B. SQC

C. SQL

D. SQI

A

13. How many sequencer steps are there in the following LLD?

A. 255

B. 100

C. 521

D. 355

D

14. The total number of steps for SQO, SQC, and SQL are specified in the ____ section.

A. file

B. source

C. length

D. position

C

15. In the following figure, the position is at Step 3. Which output ports are energized

A. 0:2/0, 0:2/1, 0:2/3, 0:2/6, 0:2/8, and 0:2/10

B. 0:2/1, 0:2/3, 0:2/6, 0:2/8, and 0:2/10

C. 0:2/1, 0:2/3, 0:2/6, and 0:2/8

D. 0:2/0, 0:2/2, and 0:2/4

D

16. Which of the following statements is true?

A. R6:0/FD can be used in SQO instruction.

B. R6:0/FD can be used by SQL instruction.

C. R6:0/FD can be used by SQC instruction.

D. All of the above.

C

17. Which of the following statements is true?

A. R6:0/DN can be used by SQO instruction.

B. R6: 0/DN can be used by SQL instruction.

C. R6: 0/DN can be used by SQC instruction.

D. All of the above.

D

18. Which of the following statements is true?

A. R6:0/EN can be used by SQO instruction.

B. R6:0/EN can be used by SQL instruction.

C. R6:0/EN can be used by SQC instruction.

D. All of the above.

D

19. You can use register R6:0 as a control register in a sequencer output (SQO) instruction. T/F

T

20. The normally open contact R6:0/DN will close whenever the sequencer output (SQO) instruction is enabled.

F

21. The normally open contact R6:0/FD will close whenever the sequencer compare (SQC) instruction is enabled. T/F

F

22. File B3 may be used to hold the sequencer output (SQO) instruction’s patterns. T/F

T

23. The length parameter specifies the number of words in the sequencer file. T/F

F

24. You can step two or more sequencer instructions simultaneously. T/F

T

25. You must use the reset (RES) instruction to reset the SQO instruction. T/F

T

26. The .LEN and .POS can hold numbers up to 256 since an SQO can have up to 256 steps. T/F

T

27. There are 255 16-bit words in file B3. T/F

F

28. There are 255 16-bit words in file B10. T/F

F

29. The control registers used by sequencer functions SQO, SQL, and SQC are R6:0 through R6:255. T/F

T

30. The ______________________________ instruction transfers data from the sequencer source file to the

output destination module

SQO

31. The ______________________________ instruction is used to control several outputs with multiple step

patterns.

sequencer

32. PLC manufacturers use the table-to-register or file-to-word instruction instead of the

______________________________ instruction

sequencer

33. The normally open ______________________________ input must be closed to energize the sequencer

instruction.

enable

34. When the normally open ______________________________ input is closed, the sequencer instruction

resets to the first output pattern.

reset

35. A low-to-high pulse on the ______________________________ input causes the sequencer to advance to the

next output pattern.

step

36. The number of ______________________________ indicates the number of data patterns the sequencer

instruction must step through.

steps

37. The ______________________________ register holds the first data pattern.

starting

38. The ______________________________ register points to the step that the instruction is on.

step pointer

39. The ______________________________ register is an output group register that indicates the output

terminals on which data is placed.

destination

40. The ______________________________ parameter in the sequencer block holds the total number of steps

that must be completed before the sequencer done status bit (R6:0/DN) coil is energized.

sequencer length

41. The ______________________________ parameter indicates the step that is desired to start the sequencer

instruction.

sequencer position

42. The ______________________________ instruction reads input data from an input module or register and

then compares the input data to the step patterns in a bit data file (B3 or B10) or integer data file (N7).

SQC

43. The ______________________________ instruction is used to read the PLC input module and store the input

data in a file.

SQL

44. The number of sequencer steps can be increased by connecting two sequencers in a(n)

______________________________ arrangement.

cascading

45. The number of outputs that are controlled by the sequencer system can be increased by connecting sequencers

in ______________________________.

parallel