On-Off Temperature Control in PLC Ladder Logic | Compare Instructions Example
This lesson explains an on-off temperature-control program in PLC ladder logic. Using an oven-heater example, it shows how thermocouple input is moved into memory, how less-than-or-equal and greater-than-or-equal compare instructions switch low-temperature and high-temperature states, and how the heater cycles between lower and upper thresholds to hold an average setpoint. Useful for PLC and process-control students.