FANUC Safety Standards & Compliance in Robotics 4 — Questions and Answers
Question 1: What is the maximum allowable transient contact force per ISO/TS 15066 for the hand/finger area when a cobot makes unintended contact?
- 140 N (Correct answer)
- 280 N
- 65 N
- 50 N
Correct answer: 140 N
ISO/TS 15066 Annex A specifies a quasi-static force limit of 140 N for the hand/finger body region during unintended collaborative robot contact.
Question 2: In FANUC DCS, a 'Position Check' violation triggers which type of robot stop by default?
- Category 0 (power removed immediately) (Correct answer)
- Category 1 (controlled stop then power removed)
- Category 2 (controlled stop, power maintained)
- Soft stop with warning only
Correct answer: Category 0 (power removed immediately)
A DCS Position Check violation triggers a Category 0 stop — immediate removal of servo power — because it indicates the robot has exceeded its defined safe working envelope.
Question 3: Which body administers the RIA (Robotic Industries Association) standards that FANUC robots must comply with in the US?
- OSHA
- NFPA
- A3 (Association for Advancing Automation) (Correct answer)
- ANSI
Correct answer: A3 (Association for Advancing Automation)
RIA is now part of A3 (Association for Advancing Automation), which develops and administers the ANSI/RIA R15.06 standard for industrial robot safety in the US.
Question 4: When validating a safety-rated monitoring function on a FANUC robot, what must be verified per ISO 13849-1 to confirm the achieved Performance Level (PL)?
- Only the MTTFd of each component
- MTTFd, DCavg, CCF measures, and system architecture (category) (Correct answer)
- Only the system architecture category
- Only the software safety integrity level
Correct answer: MTTFd, DCavg, CCF measures, and system architecture (category)
ISO 13849-1 PL validation requires calculating MTTFd (mean time to dangerous failure), DCavg (diagnostic coverage), applying CCF (common cause failure) measures, and verifying the architectural category.
Question 5: A FANUC robot cell uses a safety-rated door interlock. According to ANSI/RIA R15.06, what must happen before the safeguarding device can be muted to allow material transfer?
- The operator must verbally confirm safety
- A muting function with defined time limits and additional safeguards must be in place (Correct answer)
- The robot must be powered off completely
- The PLC must log the muting event only
Correct answer: A muting function with defined time limits and additional safeguards must be in place
Muting (temporarily suspending) a safeguarding device is only permitted when a properly designed muting function with time/position limits and supplemental safeguards is implemented per ANSI/RIA R15.06.
Question 6: According to ISO 10218-2, who bears primary responsibility for the overall safety of an integrated robotic system (the complete robot cell)?
- The robot manufacturer (e.g., FANUC)
- The end user/operator
- The system integrator (Correct answer)
- OSHA inspectors
Correct answer: The system integrator
ISO 10218-2 places primary responsibility for the safety of the integrated robot system on the system integrator, who designs and installs the complete cell.
Question 7: What is the purpose of 'speed monitoring' in FANUC's DCS compared to a simple software speed override?
- DCS speed monitoring is a non-safety-rated function for production efficiency
- DCS speed monitoring is a safety-rated function executed by a dedicated safety CPU independent of the main motion controller (Correct answer)
- Both DCS and software override use the same CPU and provide equal safety assurance
- DCS speed monitoring only applies during T2 mode
Correct answer: DCS speed monitoring is a safety-rated function executed by a dedicated safety CPU independent of the main motion controller
FANUC DCS speed monitoring runs on a dedicated safety-rated CPU that independently verifies TCP speed, providing a hardware-level safety function that is separate from and not defeatable by the main motion controller.
FANUC Safety Standards & Compliance in Robotics 4
What is the maximum allowable transient contact force per ISO/TS 15066 for the hand/finger area when a cobot makes unintended contact?