Plant Operator Selection System Test Process Control and Instrumentation 2

Question 1

In process control, 'cascade control' means:

Accepted Answer

Two controllers where the output of the primary sets the setpoint of the secondary

Answer

In cascade control, the primary (master) controller's output drives the setpoint of the secondary (slave) controller, improving disturbance rejection.

Question 2

A Safety Instrumented System (SIS) is designed to:

Accepted Answer

Automatically bring the process to a safe state when a dangerous condition is detected

Answer

The SIS is an independent layer of protection that takes automatic action (shutdown, depressurization, etc.) when the BPCS fails to prevent a hazardous condition.

Question 3

Which instrument tag designation on a P&ID indicates a flow controller?

Accepted Answer

FC

Answer

In ISA instrument tag notation, 'F' is the measured variable (flow) and 'C' is the function (controller), making FC a flow controller.

Question 4

Dead band in a control instrument refers to:

Accepted Answer

The range over which input changes cause no output response

Answer

Dead band is the input change range that produces no detectable change in output, often caused by mechanical friction or hysteresis in final control elements.

Question 5

When a process control loop is placed in 'manual' mode by the operator, it means:

Accepted Answer

The operator directly sets the controller output and the setpoint is ignored

Answer

In manual mode, the operator fixes the controller output at a chosen value while the automatic setpoint-based calculation is suspended.

Plant Operator Selection System Test Practice Test

Plant Operator Selection System Test Practice Test

Plant Operator Selection System Test Process Control and Instrumentation 2