FANUC Safety Standards & Compliance in Robotics 5

Question 1

Under NFPA 79 (Electrical Standard for Industrial Machinery), what color must the emergency stop actuator (push button) be on a FANUC robot control panel?

Accepted Answer

Red with yellow background

Answer

NFPA 79 requires the emergency stop actuator to be red with a yellow background to provide maximum visual contrast and immediate identification.

Question 2

Which safeguarding method defined in ISO 10218-2 uses robot force and power limiting to make physical contact with a human inherently safe?

Accepted Answer

Power and force limiting (PFL)

Answer

Power and Force Limiting (PFL) is the collaborative method where the robot's hardware or control system inherently limits contact forces to safe levels, allowing direct human contact.

Question 3

A FANUC robot's emergency stop circuit must be designed to which safety circuit category per IEC 60204-1 to achieve a safety-rated stop?

Accepted Answer

Category 4 — redundant, self-monitoring with high diagnostic coverage

Answer

E-stop circuits on industrial robots typically require IEC 60204-1 Category 4 safety relay architecture with dual-channel redundancy and high diagnostic coverage to achieve PLe/SIL 3.

Question 4

When a FANUC robot is operated in 'Automatic mode' with the safeguarding in place, what additional device is required before the robot can be restarted after a safety stop?

Accepted Answer

A deliberate manual reset of the safety circuit is required

Answer

After a safety stop in automatic mode, ANSI/RIA R15.06 and ISO 10218 require a deliberate manual reset action to prevent unintended automatic restart.

Question 5

In ISO 13849-1, what does 'CCF' (Common Cause Failure) refer to in the context of a FANUC dual-channel safety circuit?

Accepted Answer

Failures in both channels caused by the same root cause, defeating the redundancy

Answer

CCF is when a single cause (e.g., overvoltage, temperature, EMI) simultaneously fails both channels of a redundant safety system, eliminating the protection that redundancy is designed to provide.

(FANUC) Fuji Automatic Numerical Control Robotics Certification Practice Test

(FANUC) Fuji Automatic Numerical Control Robotics Certification Practice Test

FANUC Safety Standards & Compliance in Robotics 5