SACA Safety Systems and Functional Safety 4

Question 1

What does the term 'safe state' mean in the context of functional safety?

Accepted Answer

A condition in which the system does not pose an unacceptable risk

Answer

A state where the system is powered off completely

Answer

A state where all diagnostics have passed

Answer

A mode with maximum operational speed enabled

Question 2

In IEC 61511, what is the primary purpose of a Safety Instrumented Function (SIF)?

Accepted Answer

To bring a process to a safe state upon demand

Answer

To optimize process efficiency

Answer

To log operational data for audits

Answer

To control normal process variables

Question 3

Which failure mode is addressed by 'deenergize-to-trip' design philosophy in safety systems?

Accepted Answer

Power supply failures causing loss of safe actuation

Answer

Common cause failures

Answer

Dangerous undetected failures

Answer

Systematic failures in software

Question 4

What is the purpose of proof testing in a Safety Instrumented System?

Accepted Answer

To detect dangerous undetected faults and restore the PFD to its initial value

Answer

To verify the system meets production throughput targets

Answer

To calibrate process transmitters for accuracy

Answer

To test cybersecurity controls on the SIS network

Question 5

In a redundant 2oo3 voting architecture, how many channels must agree on a fault for a trip to occur?

Accepted Answer

2 out of 3

Answer

1 out of 3

Answer

3 out of 3

Answer

Any single channel independently

Question 6

Which IEC standard specifically addresses functional safety of electrical/electronic/programmable electronic safety-related systems in general industry?

Accepted Answer

IEC 61508

Answer

IEC 61511

Answer

IEC 62061

Answer

ISO 13849

Question 7

What does 'spurious trip rate' measure in a Safety Instrumented System?

Accepted Answer

The rate at which the system initiates unintended safe shutdowns

Answer

The frequency of dangerous process deviations detected

Answer

The number of proof tests performed per year

Answer

The probability that a hazardous event reaches the environment