Runnable simulator field guide
Emergency-stop reset PLC scenario: test checklist
Direct answer
The learner can make the simulated machine stop on demand, block reset until the declared conditions are healthy and prove that reset alone does not restart motion.
Written for pLC and machine-safety learners examining the distinction between a protective demand, fault acknowledgement, reset and a separate machine start request.
Scenario setup
Hazard boundary, emergency-stop device state, dual-channel concept, safety state, machine commands, physical stop feedback, reset eligibility, reset edge, fault latch, start request and power-return policy.
I/O and state map
Protective demand through simulated safety state to removal of motion permission, stopped feedback, cause clearance, deliberate reset and separately authorized restart.
Normal run
Every E-stop demand removes simulated motion permission and a healthy reset returns only to a ready, non-running state.
Boundary run
Device held, one channel discrepant, reset held, reset before stopped feedback, start held, cause returns, controller restart and power return.
Injected fault
A requirement, device, channel, safety-state, output, stop-feedback, reset, start or restart-policy mismatch.
Target check
The target emergency-stop function engineered and validated by qualified people against the risk assessment and current safety standards.
Should resetting an emergency stop restart a machine?
A reset should restore eligibility only; restart behavior must be risk-assessed and generally requires a separate deliberate start action.
Why must the E-stop device be released before reset?
The initiating protective demand must be cleared and all defined conditions healthy before the system can become eligible for a deliberate reset.