This controller provides reliable temperature management with four core features: heating control, delay operation, cooling control, and a temperature alarm. Key features and benefits Heating mode H When the detected temperature is at or below set temperature minus the hysteresis, the relay closes and the heating equipment starts. When the detected temperature reaches or exceeds the set temperature, the relay opens and the heating stops. Benefits: stable heating with hysteresis to reduce overshoot and excessive cycling, improving efficiency and equipment life. Delay OPH After completing a normal heating or cooling cycle, the system starts a timer T. A heating or cooling cycle can proceed only when T ≥ OPH. Benefits: prevents rapid cycling, enhances system stability, and protects connected devices. Cooling mode C When the detected temperature is at or above set temperature plus the hysteresis, the relay closes and the cooling equipment starts. When the detected temperature reaches or falls below the set temperature, the relay opens and the cooling stops. Benefits: reliable cooling control with defined hysteresis to maintain steady temperatures. temperature alarm function ALA When the actual temperature reaches or exceeds the alarm temperature, the system activates audible and visual alarm indicators and disconnects the relay. Any key can stop the sound and light alarm. Benefits: enhanced safety with immediate alert and a straightforward way to acknowledge and reset the alarm. Compatibility and usage Designed to control standard relay driven heating and cooling equipment using simple on off (relay) control. Suitable for environments where maintaining a safe and stable temperature is important and where a clear alarm is required for overtemperature conditions. Performance and practicality Applies precise hysteresis based control for both heating and cooling to minimize temperature fluctuation. Includes a deliberate delay to prevent short cycling and extend equipment life. Provides a clear temperature alarm to protect personnel and assets, with easy alarm acknowledgment. Use scenarios Industrial equipment enclosure: Use heating to prevent condensation or cooling to maintain safe operating temperatures, with a delay to avoid rapid cycling and an alarm for overtemperature events. Greenhouse or storage room: Maintain a narrow temperature band to protect crops or perishable goods, switching heater or cooler as needed. Laboratory incubator or small chamber: Manage temperature within a defined range for experiments or sample storage, with an alarm to indicate unsafe conditions. This description preserves the original feature set and terminology (Heating mode H, Delay OPH, Cooling mode C, temperature alarm ALA) while presenting clear, customerfriendly information about function, benefits, compatibility, and practical use.