Hypothetical design case
Manual teaching with a three-position enabling device
Follow the whole function and distinguish device data from achieved PL.
Reviewed 2026-11-04 · Engineering interpretation · authoring reviewed
Scenario and inputs
Hypothetical operator inside the restricted space in an assessed manual mode. Consider trapping and unintended motion. Proposed inputs are mode selection, enabling switch and a separate jog command. Establish tool and adjacent-machine behavior before entry.
Function and safe state
For this example, released and fully squeezed positions remove enabling. The middle position permits separately commanded motion within assessed limits. Chain: enabling and mode inputs → safety logic → robot motion and stop functions. Loss of enabling invokes the specified stopped state while gravity and tool hazards are controlled. The UR18 reference documents the off–on–off device behavior for that product.
Reliability boundary
The UR10e reference explains that the complete integrated function depends on its connected equipment and architecture. A switch certificate or robot subsystem PFHd is an assessment input. It does not establish the PL of this hypothetical complete function. Establish PLr from applicable robot requirements and the risk assessment, then evaluate the actual chain.
Evidence and proposed tests
Identify switch, mode selector, controller, drives and wiring. Test release, full squeeze, passage back through the middle, channel faults, a held jog command during re-enable and mode change. Record the expected transition before testing. PLr, achieved PL, allowed speed and stopping behavior remain unassigned.
Sources & editions
Universal Robots UR18, Safety Functions Table ↗
PolyScope SW5.24 manual
SF18 and footnote 11, product-specific enabling behavior
Universal Robots UR10e, Safety Functions Table ↗
PolyScope SW5.20 manual
Description, connected equipment and complete safety function
Robot Safety Forum original engineering notes
Initial publication edition 2026-11-04
Proposed teaching scenario, boundary and fault tests