More than one pushbutton station (operator’s control station) can be installed for a given control line in a control circuit (line or ladder diagram).
Multiple NC Stop PB switches must be wired in ____________ to form a NOR logic gate (circuit).
A) either series or parallel
B) series
C) none of the answers
D) parallel
Answer:B
Share your understanding of this question with the correct explanation.
Explanation:
Multiple NC (Normally Closed) Stop Pushbutton (PB) switches must be wired in series to form a NOR logic gate (circuit).
In control circuits, Normally Closed (NC) Stop Pushbutton switches are commonly used as safety devices to provide an emergency stop function. When the Stop PB is not pressed (in its normal state), it allows current to flow through the circuit. When the Stop PB is pressed, it opens the circuit and interrupts the flow of current, causing the controlled machine or process to stop.
A NOR (NOT-OR) logic gate is a digital logic gate that outputs true (1) only when all of its inputs are false (0). When multiple NC Stop PB switches are wired in series, they create a NOR gate configuration. In this setup, if any one of the NC Stop PB switches is pressed (open state), the circuit is interrupted, and the output of the NOR gate becomes true (1), causing the controlled machine or process to stop.
Wiring the NC Stop PB switches in series means connecting the normally closed contacts in a chain, so the current flows through each switch consecutively. If any one of the switches is opened (Stop PB is pressed), the circuit becomes open, and the output becomes true, stopping the operation.
In summary, for a NOR logic gate configuration using NC Stop Pushbutton switches, they must be wired in series.