Industrial Temperature Controller with Dual Relays
- Client
- Processing & manufacturing industry
- Year
- 2023
- Category
- Industrial Automation
NELSco designed an STM8-based single-loop temperature controller for greenhouse, packaging, and heating applications. The digital DS18B20 interface reduces the analog signal path; application-level EMC performance still depends on wiring, installation, and validation.
Digital DS18B20 sensing over 1-Wire using the sensor manufacturer's stated ±0.5°C specification over the applicable range; whole-system accuracy depends on installation and calibration.
Configurable hysteresis to reduce relay chatter, sensor-fault handling, configurable power-on delay, non-volatile EEPROM settings, and 100–240 V AC or 24 V DC input variants.
The Challenge
Long analog measurement paths can be susceptible to noise, insufficient hysteresis can increase relay switching, and power loss must not erase settings. The project needed an affordable, configurable digital controller for defined applications.
Our Approach
Temperature is measured with a DS18B20 over 1-Wire; ±0.5°C over the stated range is the sensor manufacturer's specification, not whole-system accuracy without calibration and validation. The design includes two relay outputs, adjustable hysteresis to reduce switching near the setpoint, sensor-fault handling, a configurable power-on delay, non-volatile settings, and 100–240 V AC or 24 V DC variants.
The Result
The controller can be evaluated as a configurable digital alternative to analog units in defined applications. Electrical, mechanical, and control compatibility must be confirmed for each installation.
Results
- Configurable digital alternative to analog controllers in defined applications
- Reduces relay chatter and associated switching wear through configurable hysteresis
- Retains settings after power loss via non-volatile EEPROM
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