Runnable simulator field guide
Temperature setpoint PLC scenario: test checklist
Direct answer
The learner can validate units and quality, clamp an authorized setpoint, control around it without chatter and prove high-temperature and sensor-fault response.
Written for process-control learners joining an analog temperature measurement to an operator setpoint and bounded heater command.
Scenario setup
Sensor range and quality, engineering unit, setpoint authority and limits, deadband or controller mode, heater permissives, output, high alarm and independent limit.
I/O and state map
Physical temperature through sensor and input scaling to control comparison, heater command, heat transfer, measured response and protective boundary.
Normal run
A valid measurement below setpoint permits bounded heating and settles within the declared band without defeating stop or high-limit behavior.
Boundary run
Bad sensor, frozen value, setpoint beyond limit, overshoot, rapid cycling, no heat, stuck output, manual mode, restart and power return.
Injected fault
A sensor, loop, scale, unit, setpoint, permission, control, output, thermal-process or protective-boundary mismatch.
Target check
The strategy validated on the intended thermal process with exact instruments, hardware limits, tuning and safety analysis.
How should a PLC limit a temperature setpoint?
Validate numeric type and units, apply role-based lower and upper engineering limits and show the accepted value separately from the requested value.
What should happen when the temperature sensor fails?
Remove or constrain automatic heating according to the approved hazard analysis, declare bad quality and require a deliberate recovery path.