A safety-rated monitored stop halts a robot — with power still on — whenever a person enters its shared space, and lets it resume automatically when they leave, the simplest of the four collaborative-safety methods.
A safety-rated monitored stop makes a robot pause and hold still (but stay powered) when a person steps into its area, then continue on its own once the person steps back out — no button press needed to restart.
🎯 Quick challenge
A safety-rated monitored stop differs from an emergency stop in that it…
The simplest way to let a person safely enter a robot's space is also intuitive: the robot just stops and waits while they're there, then carries on when they leave. That's a safety-rated monitored stop (SRMS).
What it is
A safety-rated monitored stop puts the robot into a monitored standstill: it holds its position and keeps power on (so it's still holding a part, still ready) but does not move while a human is in the shared zone. Safety-rated sensors (area scanners, light curtains, mats) detect the person's presence, and safety-rated logic guarantees the robot truly is stopped. When the person leaves, the robot resumes automatically — no manual restart.
Stop while present, resume when clear
The robot pauses only while someone shares its space, then continues on its own — enabling safe hand-offs and shared tasks without a full shutdown.
SRMS vs emergency stop
They sound similar but serve different roles:
Emergency stop — a hard, latched halt (often cutting power) for a fault or danger; requires a deliberate human reset to restart.
Safety-rated monitored stop — a routine, automatic pause for collaboration; power stays on, position is held, and it resumes by itself when safe.
SRMS is for the normal rhythm of people and robots sharing a task; the e-stop is the emergency backstop.
Where it fits
SRMS is the first and simplest of the four collaborative methods in ISO/TS 15066, alongside hand guiding, speed and separation monitoring, and power and force limiting. It's common in hand-off stations (a robot presents a part, stops while the worker takes it, resumes) and shared cells where a person only occasionally enters. Because the robot fully stops when anyone is near, it's easy to justify safely — the trade-off being lost productivity during those pauses (which SSM avoids by slowing rather than stopping).
Why it matters
The safety-rated monitored stop is a foundational, easy-to-understand method for human-robot collaboration — letting people safely share a robot's space with automatic, frictionless resumption. It's often the entry point to fenceless operation and a building block of flexible, collaborative automation.
