Learn the Siemens PLC programming with a detailed understanding of Organization Blocks (OB) for beginners and freshers.
Siemens PLC Organization Blocks
Test your knowledge of Siemens PLC OB blocks.
Question 1
What is the purpose of OB1 in Siemens PLCs?
A. Manages cold restart
B. Handles power supply faults
C. Executes the main program cycle
D. Monitors communication errors
Show the Answer
Executes the main program cycle
Question 2
Which Siemens PLC organization block is triggered during a cold restart?
A. OB4
B. OB100
C. OB2
D. OB3
Show the Answer
OB2
Question 3
What happens when OB3 is triggered in a Siemens PLC?
A. Time of day interrupt
B. Cold restart
C. Startup block execution
D. Warm restart
Show the Answer
Warm restart
Question 4
Which OB is responsible for handling a hot restart in Siemens PLCs?
A. OB4
B. OB2
C. OB35
D. OB3
Show the Answer
OB4
Question 5
What is the role of OB5 in Siemens PLC systems?
A. Power supply management
B. Manages rack failures
C. Startup organization block
D. Handles time delay interrupts
Show the Answer
Startup organization block
Question 6
When is OB6 triggered in a Siemens PLC?
A. On time delay
B. On cyclic interrupt
C. On diagnostic interrupt
D. On delay interrupt
Show the Answer
On delay interrupt
Question 7
Which OB handles time-of-day-based operations in Siemens PLCs?
A. OB87
B. OB7
C. OB6
D. OB80
Show the Answer
OB7
Question 8
What is the purpose of OB8 in Siemens PLC systems?
A. Manages hardware interrupts
B. Monitors communication errors
C. Deals with power supply faults
D. Handles cyclic interrupts
Show the Answer
Handles cyclic interrupts
Question 9
Which Siemens PLC OB is responsible for time error interruptions?
A. OB35
B. OB40
C. OB121
D. OB10
Show the Answer
OB10
Question 10
When is OB20 triggered in Siemens PLCs?
A. On module insertion/removal
B. During diagnostic data monitoring
C. When a time delay interrupt occurs
D. When there is a communication error
Show the Answer
When a time delay interrupt occurs
Question 11
What is the role of OB30 in Siemens PLCs?
A. Handles diagnostic interrupts
B. Handles cyclic interrupts
C. Monitors I/O access errors
D. Manages hardware failure
Show the Answer
Handles diagnostic interrupts
Question 12
What is the significance of OB35 in Siemens PLCs?
A. Time delay interrupt
B. Configurable time for cyclic interrupts
C. Manages rack failures
D. Power supply error handling
Show the Answer
Configurable time for cyclic interrupts
Question 13
When does OB40 execute in Siemens PLCs?
A. During a hardware interrupt
B. During a power supply failure
C. After a cold restart
D. During a programming error
Show the Answer
During a hardware interrupt
Question 14
What condition triggers OB80 in Siemens PLC?
A. I/O access error
B. Time error
C. Power supply failure
D. Diagnostic data failure
Show the Answer
Time error
Question 15
What does OB81 handle in Siemens PLCs?
A. Time delay interrupts
B. Communication errors
C. Cyclic interrupts
D. Power supply faults
Show the Answer
Power supply faults
Question 16
What is the purpose of OB82 in Siemens PLC?
A. Tracks rack failures
B. Monitors diagnostic errors
C. Handles module insertion/removal
D. Manages I/O access errors
Show the Answer
Monitors diagnostic errors
Question 17
What happens when OB83 is triggered in Siemens PLC?
A. Communication error detected
B. Power supply fault
C. Time error handling
D. Module insertion/removal detected
Show the Answer
Module insertion/removal detected
Question 18
What condition activates OB85 in Siemens PLC?
A. Program cycle error
B. Diagnostic data failure
C. I/O access error
D. Hardware interrupt
Show the Answer
Program cycle error
Question 19
What does OB86 manage in Siemens PLCs?
A. Programming errors
B. Time delay interrupts
C. Rack failures
D. Power supply faults
Show the Answer
Rack failures
Question 20
What kind of error triggers OB87 in Siemens PLC systems?
A. Communication error
B. Diagnostic data failure
C. I/O access error
D. Power supply fault
Show the Answer
Communication error
Question 21
When is OB88 executed in Siemens PLCs?
A. After a module is inserted or removed
B. When diagnostic data is collected
C. During a warm restart
D. When a time error occurs
Show the Answer
When diagnostic data is collected
Question 22
What is the function of OB100 in Siemens PLC?
A. Manages hardware interrupts
B. Executes during startup
C. Monitors diagnostic data
D. Handles warm restarts
Show the Answer
Executes during startup
Question 23
Which OB is responsible for programming errors in Siemens PLCs?
A. OB121
B. OB10
C. OB80
D. OB85
Show the Answer
OB121
Question 24
What happens when OB122 is triggered in Siemens PLC?
A. I/O access error occurs
B. Program cycle completes
C. Power supply failure
D. Diagnostic data is collected
Show the Answer
I/O access error occurs
Question 25
What is the function of OB41 in Siemens PLC systems?
A. Manages hardware interrupts
B. Handles time delay interrupts
C. Deals with power supply faults
D. Monitors cyclic interrupts
Show the Answer
Handles time delay interrupts
Question 26
What happens when OB42 is triggered in a Siemens PLC?
A. Communication error detected
B. Isochronous mode execution begins
C. Diagnostic interrupt occurs
D. Power failure detected
Show the Answer
Isochronous mode execution begins
Question 27
When is OB55 executed in Siemens PLC systems?
A. When a time delay occurs
B. For time-of-day synchronization
C. On communication failure
D. During hardware interrupt
Show the Answer
For time-of-day synchronization
Question 28
What is the purpose of OB56 in Siemens PLCs?
A. Handles isochronous mode synchronization
B. Manages warm restart
C. Monitors cyclic interrupts
D. Deals with I/O redundancy errors
Show the Answer
Handles isochronous mode synchronization
Question 29
What does OB84 handle in Siemens PLC systems?
A. Communication synchronization
B. I/O redundancy errors
C. Isochronous mode execution
D. Time-of-day synchronization
Show the Answer
I/O redundancy errors
Question 30
What is the role of OB72 in Siemens PLC systems?
A. Detects time delay interrupts
B. Handles communication errors
C. Manages CPU redundancy errors
D. Monitors I/O access failures
Show the Answer
Manages CPU redundancy errors
