ISA Certified Control Systems Technician
(CCST) Level III Practice Exam Questions
And Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant
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Includes All Subject Areas (Calibration, Troubleshooting, Documentation,
Process Control, Safety, etc.)
1. A control valve with a split-range configuration is typically used to:
A. Control two process variables simultaneously
B. Share one control signal between two valves operating in opposite
directions
C. Provide redundancy in control loops
D. Compensate for nonlinear valve characteristics
Rationale: Split-range valves respond to different signal portions to control
opposing actions, such as heating and cooling.
,2. The main purpose of a three-element boiler drum level control system is
to:
A. Measure only drum level
B. Measure feedwater flow only
C. Compensate for steam flow and feedwater flow to stabilize drum level
D. Reduce boiler pressure
Rationale: Three-element control measures drum level, steam flow, and
feedwater flow to balance inflow and outflow.
3. In a cascade control system, the output of the primary controller:
A. Directly controls the final control element
B. Is used only for monitoring
C. Provides the setpoint to the secondary controller
D. Is averaged with the secondary controller output
Rationale: The primary (master) controller drives the secondary (slave)
controller’s setpoint to enhance control precision.
4. A “live zero” current signal (e.g., 4–20 mA) allows detection of:
A. Process variable saturation
B. Open circuit or instrument failure
C. Linear response error
,D. Reverse polarity
Rationale: Live zero ensures that 0 mA indicates a fault, differentiating
from valid low readings.
5. The most accurate standard for calibration in a process measurement
hierarchy is known as the:
A. Field standard
B. Working standard
C. Primary standard
D. Secondary standard
Rationale: Primary standards are reference-grade devices used for
traceability to national or international standards.
6. The term “deadband” in control systems refers to:
A. The maximum deviation allowed before alarming
B. The offset in a proportional-only controller
C. The range where no corrective action occurs despite input changes
D. The maximum gain setting of a PID controller
Rationale: Deadband is the insensitive zone where the controller output
doesn’t change within small input variations.
, 7. A 12-bit digital signal has how many discrete levels?
A. 1024
B. 4096
C. 2048
D. 8192
Rationale: Number of levels = 2ⁿ = 2¹² = 4096.
8. A 4–20 mA signal represents a temperature range of 0–200°C. What
temperature does a 12 mA signal represent?
A. 75°C
B. 100°C
C. 125°C
D. 150°C
Rationale: (12–4)/(20–4)=0.5; 0.5×200=100°C.
9. The main advantage of using a differential pressure (DP) transmitter for
flow measurement is:
A. It can measure any fluid directly
B. It provides a square root relationship for flow rate
C. It eliminates temperature compensation
D. It does not require calibration
Rationale: DP flow uses the square root of pressure difference to represent
flow, following Bernoulli’s principle.
(CCST) Level III Practice Exam Questions
And Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant
Download Pdf
Includes All Subject Areas (Calibration, Troubleshooting, Documentation,
Process Control, Safety, etc.)
1. A control valve with a split-range configuration is typically used to:
A. Control two process variables simultaneously
B. Share one control signal between two valves operating in opposite
directions
C. Provide redundancy in control loops
D. Compensate for nonlinear valve characteristics
Rationale: Split-range valves respond to different signal portions to control
opposing actions, such as heating and cooling.
,2. The main purpose of a three-element boiler drum level control system is
to:
A. Measure only drum level
B. Measure feedwater flow only
C. Compensate for steam flow and feedwater flow to stabilize drum level
D. Reduce boiler pressure
Rationale: Three-element control measures drum level, steam flow, and
feedwater flow to balance inflow and outflow.
3. In a cascade control system, the output of the primary controller:
A. Directly controls the final control element
B. Is used only for monitoring
C. Provides the setpoint to the secondary controller
D. Is averaged with the secondary controller output
Rationale: The primary (master) controller drives the secondary (slave)
controller’s setpoint to enhance control precision.
4. A “live zero” current signal (e.g., 4–20 mA) allows detection of:
A. Process variable saturation
B. Open circuit or instrument failure
C. Linear response error
,D. Reverse polarity
Rationale: Live zero ensures that 0 mA indicates a fault, differentiating
from valid low readings.
5. The most accurate standard for calibration in a process measurement
hierarchy is known as the:
A. Field standard
B. Working standard
C. Primary standard
D. Secondary standard
Rationale: Primary standards are reference-grade devices used for
traceability to national or international standards.
6. The term “deadband” in control systems refers to:
A. The maximum deviation allowed before alarming
B. The offset in a proportional-only controller
C. The range where no corrective action occurs despite input changes
D. The maximum gain setting of a PID controller
Rationale: Deadband is the insensitive zone where the controller output
doesn’t change within small input variations.
, 7. A 12-bit digital signal has how many discrete levels?
A. 1024
B. 4096
C. 2048
D. 8192
Rationale: Number of levels = 2ⁿ = 2¹² = 4096.
8. A 4–20 mA signal represents a temperature range of 0–200°C. What
temperature does a 12 mA signal represent?
A. 75°C
B. 100°C
C. 125°C
D. 150°C
Rationale: (12–4)/(20–4)=0.5; 0.5×200=100°C.
9. The main advantage of using a differential pressure (DP) transmitter for
flow measurement is:
A. It can measure any fluid directly
B. It provides a square root relationship for flow rate
C. It eliminates temperature compensation
D. It does not require calibration
Rationale: DP flow uses the square root of pressure difference to represent
flow, following Bernoulli’s principle.
