30 real Process Control Design questions from the Process Design bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.
1. What is Cascade control?
Junior
A.model-based rule choosing the closed-loop time constant so controller gain equals τ/(K·λ), giving non-oscillatory response and robustness to model error
B.safety instrumented system stays independent of the basic control system with its own sensors, logic solver and final elements, certified under IEC 61511
C.lifecycle standard for alarm rationalisation targeting about six alarms per operator-hour and fewer than ten standing alarms, with priority and shelving rules
D.master loop output sets the set point of a faster inner loop, such as temperature setting steam flow, to reject inner disturbances early
2. Which term means: "master loop output sets the set point of a faster inner loop, such as temperature setting steam flow, to reject inner disturbances early"?
A.Cascade control — distributed controllers on a redundant network with operator stations, engineering station and historian, typically scanning regulatory loops every second or faster
B.Cascade control — one controller output drives two valves over different ranges, such as vent gas above 50% and inert make-up below, for blanket pressure
C.Cascade control — master loop output sets the set point of a faster inner loop, such as temperature setting steam flow, to reject inner disturbances early
D.Cascade control — safety instrumented system stays independent of the basic control system with its own sensors, logic solver and final elements, certified under IEC 61511
A.one controller output drives two valves over different ranges, such as vent gas above 50% and inert make-up below, for blanket pressure
B.measured disturbance is used to adjust the manipulated variable before the process variable deviates, always paired with feedback trim
C.safety instrumented system stays independent of the basic control system with its own sensors, logic solver and final elements, certified under IEC 61511
D.lifecycle standard for alarm rationalisation targeting about six alarms per operator-hour and fewer than ten standing alarms, with priority and shelving rules
5. Which term means: "measured disturbance is used to adjust the manipulated variable before the process variable deviates, always paired with feedback trim"?
A.Feedforward control — one controller output drives two valves over different ranges, such as vent gas above 50% and inert make-up below, for blanket pressure
B.Feedforward control — measured disturbance is used to adjust the manipulated variable before the process variable deviates, always paired with feedback trim
C.Feedforward control — equal-percentage suits variable pressure drop and wide turndown; linear suits constant drop; quick-opening suits on-off duty
D.Feedforward control — distributed controllers on a redundant network with operator stations, engineering station and historian, typically scanning regulatory loops every second or faster
A.model-based rule choosing the closed-loop time constant so controller gain equals τ/(K·λ), giving non-oscillatory response and robustness to model error
B.equal-percentage suits variable pressure drop and wide turndown; linear suits constant drop; quick-opening suits on-off duty
C.lifecycle standard for alarm rationalisation targeting about six alarms per operator-hour and fewer than ten standing alarms, with priority and shelving rules
D.keeps one flow at a fixed proportion of a wild flow, such as air to fuel or reflux to feed
A.Ratio control — model-based rule choosing the closed-loop time constant so controller gain equals τ/(K·λ), giving non-oscillatory response and robustness to model error
B.Ratio control — keeps one flow at a fixed proportion of a wild flow, such as air to fuel or reflux to feed
C.Ratio control — flow coefficient equal to US gallons per minute of water at 1 psi drop; the valve is chosen so required flow falls between 20% and 80% of travel
D.Ratio control — master loop output sets the set point of a faster inner loop, such as temperature setting steam flow, to reject inner disturbances early
A.measured disturbance is used to adjust the manipulated variable before the process variable deviates, always paired with feedback trim
B.flow coefficient equal to US gallons per minute of water at 1 psi drop; the valve is chosen so required flow falls between 20% and 80% of travel
C.safety instrumented system stays independent of the basic control system with its own sensors, logic solver and final elements, certified under IEC 61511
D.one controller output drives two valves over different ranges, such as vent gas above 50% and inert make-up below, for blanket pressure
11. Which term means: "one controller output drives two valves over different ranges, such as vent gas above 50% and inert make-up below, for blanket pressure"?
A.Split-range control — safety instrumented system stays independent of the basic control system with its own sensors, logic solver and final elements, certified under IEC 61511
B.Split-range control — flow coefficient equal to US gallons per minute of water at 1 psi drop; the valve is chosen so required flow falls between 20% and 80% of travel
C.Split-range control — one controller output drives two valves over different ranges, such as vent gas above 50% and inert make-up below, for blanket pressure
D.Split-range control — measured disturbance is used to adjust the manipulated variable before the process variable deviates, always paired with feedback trim
A.flow coefficient equal to US gallons per minute of water at 1 psi drop; the valve is chosen so required flow falls between 20% and 80% of travel
B.safety instrumented system stays independent of the basic control system with its own sensors, logic solver and final elements, certified under IEC 61511
C.lifecycle standard for alarm rationalisation targeting about six alarms per operator-hour and fewer than ten standing alarms, with priority and shelving rules
D.keeps one flow at a fixed proportion of a wild flow, such as air to fuel or reflux to feed
14. Which term means: "flow coefficient equal to US gallons per minute of water at 1 psi drop; the valve is chosen so required flow falls between 20% and 80% of travel"?
A.Control valve Cv — flow coefficient equal to US gallons per minute of water at 1 psi drop; the valve is chosen so required flow falls between 20% and 80% of travel
B.Control valve Cv — measured disturbance is used to adjust the manipulated variable before the process variable deviates, always paired with feedback trim
C.Control valve Cv — distributed controllers on a redundant network with operator stations, engineering station and historian, typically scanning regulatory loops every second or faster
D.Control valve Cv — lifecycle standard for alarm rationalisation targeting about six alarms per operator-hour and fewer than ten standing alarms, with priority and shelving rules
A.master loop output sets the set point of a faster inner loop, such as temperature setting steam flow, to reject inner disturbances early
B.equal-percentage suits variable pressure drop and wide turndown; linear suits constant drop; quick-opening suits on-off duty
C.keeps one flow at a fixed proportion of a wild flow, such as air to fuel or reflux to feed
D.lifecycle standard for alarm rationalisation targeting about six alarms per operator-hour and fewer than ten standing alarms, with priority and shelving rules
A.Valve characteristic — master loop output sets the set point of a faster inner loop, such as temperature setting steam flow, to reject inner disturbances early
B.Valve characteristic — lifecycle standard for alarm rationalisation targeting about six alarms per operator-hour and fewer than ten standing alarms, with priority and shelving rules
C.Valve characteristic — safety instrumented system stays independent of the basic control system with its own sensors, logic solver and final elements, certified under IEC 61511
D.Valve characteristic — equal-percentage suits variable pressure drop and wide turndown; linear suits constant drop; quick-opening suits on-off duty
A.keeps one flow at a fixed proportion of a wild flow, such as air to fuel or reflux to feed
B.lifecycle standard for alarm rationalisation targeting about six alarms per operator-hour and fewer than ten standing alarms, with priority and shelving rules
C.distributed controllers on a redundant network with operator stations, engineering station and historian, typically scanning regulatory loops every second or faster
D.flow coefficient equal to US gallons per minute of water at 1 psi drop; the valve is chosen so required flow falls between 20% and 80% of travel
20. Which term means: "lifecycle standard for alarm rationalisation targeting about six alarms per operator-hour and fewer than ten standing alarms, with priority and shelving rules"?
A.ISA 18.2 alarm management — lifecycle standard for alarm rationalisation targeting about six alarms per operator-hour and fewer than ten standing alarms, with priority and shelving rules
B.ISA 18.2 alarm management — master loop output sets the set point of a faster inner loop, such as temperature setting steam flow, to reject inner disturbances early
C.ISA 18.2 alarm management — distributed controllers on a redundant network with operator stations, engineering station and historian, typically scanning regulatory loops every second or faster
D.ISA 18.2 alarm management — equal-percentage suits variable pressure drop and wide turndown; linear suits constant drop; quick-opening suits on-off duty
A.distributed controllers on a redundant network with operator stations, engineering station and historian, typically scanning regulatory loops every second or faster
B.lifecycle standard for alarm rationalisation targeting about six alarms per operator-hour and fewer than ten standing alarms, with priority and shelving rules
C.master loop output sets the set point of a faster inner loop, such as temperature setting steam flow, to reject inner disturbances early
D.measured disturbance is used to adjust the manipulated variable before the process variable deviates, always paired with feedback trim
23. Which term means: "distributed controllers on a redundant network with operator stations, engineering station and historian, typically scanning regulatory loops every second or faster"?
A.DCS architecture — safety instrumented system stays independent of the basic control system with its own sensors, logic solver and final elements, certified under IEC 61511
B.DCS architecture — model-based rule choosing the closed-loop time constant so controller gain equals τ/(K·λ), giving non-oscillatory response and robustness to model error
C.DCS architecture — distributed controllers on a redundant network with operator stations, engineering station and historian, typically scanning regulatory loops every second or faster
D.DCS architecture — lifecycle standard for alarm rationalisation targeting about six alarms per operator-hour and fewer than ten standing alarms, with priority and shelving rules
A.master loop output sets the set point of a faster inner loop, such as temperature setting steam flow, to reject inner disturbances early
B.equal-percentage suits variable pressure drop and wide turndown; linear suits constant drop; quick-opening suits on-off duty
C.safety instrumented system stays independent of the basic control system with its own sensors, logic solver and final elements, certified under IEC 61511
D.model-based rule choosing the closed-loop time constant so controller gain equals τ/(K·λ), giving non-oscillatory response and robustness to model error
26. Which term means: "safety instrumented system stays independent of the basic control system with its own sensors, logic solver and final elements, certified under IEC 61511"?
A.SIS vs BPCS — master loop output sets the set point of a faster inner loop, such as temperature setting steam flow, to reject inner disturbances early
B.SIS vs BPCS — equal-percentage suits variable pressure drop and wide turndown; linear suits constant drop; quick-opening suits on-off duty
C.SIS vs BPCS — flow coefficient equal to US gallons per minute of water at 1 psi drop; the valve is chosen so required flow falls between 20% and 80% of travel
D.SIS vs BPCS — safety instrumented system stays independent of the basic control system with its own sensors, logic solver and final elements, certified under IEC 61511
A.equal-percentage suits variable pressure drop and wide turndown; linear suits constant drop; quick-opening suits on-off duty
B.one controller output drives two valves over different ranges, such as vent gas above 50% and inert make-up below, for blanket pressure
C.model-based rule choosing the closed-loop time constant so controller gain equals τ/(K·λ), giving non-oscillatory response and robustness to model error
D.lifecycle standard for alarm rationalisation targeting about six alarms per operator-hour and fewer than ten standing alarms, with priority and shelving rules
29. Which term means: "model-based rule choosing the closed-loop time constant so controller gain equals τ/(K·λ), giving non-oscillatory response and robustness to model error"?
A.Lambda (IMC) tuning — one controller output drives two valves over different ranges, such as vent gas above 50% and inert make-up below, for blanket pressure
B.Lambda (IMC) tuning — keeps one flow at a fixed proportion of a wild flow, such as air to fuel or reflux to feed
C.Lambda (IMC) tuning — model-based rule choosing the closed-loop time constant so controller gain equals τ/(K·λ), giving non-oscillatory response and robustness to model error
D.Lambda (IMC) tuning — lifecycle standard for alarm rationalisation targeting about six alarms per operator-hour and fewer than ten standing alarms, with priority and shelving rules
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