Overview
The RKC REX-C9 temperature controller is a microprocessor-based control instrument engineered for HVAC, refrigeration, and industrial thermal management. Part of RKC’s proven REX-C series, this controller delivers reliable, precise temperature regulation in a compact form factor. The unit combines multiple sensor input options with intelligent control algorithms to maintain stable operation in demanding environments.
Key Features
- Microprocessor-based intelligent control with self-tuning capabilities
- Multiple input options: thermocouple (TC), RTD, and analog signal support
- Fuzzy logic combined with conventional PID control for smooth, responsive regulation
- Auto-zeroing amplifier with measurement accuracy better than 0.5% FS
- Compact design with surface-mount technology (SMT) construction
- Self-diagnostic function for system monitoring and troubleshooting
Technical Specifications
The REX-C9 shares core specifications with the broader REX-C series. Input types include multiple thermocouple grades, RTD (Pt100/Pt1000), and 4-20mA analog signals. The controller offers flexible output options including relay contact, logic-level, and SCR triggering for both single-phase and three-phase applications. Operating temperature range, communication protocols, and exact I/O configurations depend on the specific option code suffix—verify with your system integrator or consult the unit’s label and documentation.
Typical Applications
- HVAC system thermostats and setpoint control
- Industrial refrigeration unit regulation
- Process temperature monitoring and management
- Cold-chain and cleanroom environmental control
- Heat-treat furnace and oven setpoint management
- Warehouse and storage facility climate monitoring
Compatibility & Replacements
Compatible With
- Standard DIN rail mounting systems
- Thermocouple and RTD sensor networks
- Analog control signal interfaces (4-20mA)
- AC power supply systems (85–250V typical)
- Relay, SCR, and logic-level output systems
Replaces / Drop-In Replacement For
The RKC REX-C9 may directly replace earlier RKC temperature control units in the same form factor. Verify compatibility with your system integrator before ordering, as replacement compatibility depends on specific electrical specifications and mounting dimensions of your existing installation.
Works With
- RKC communication protocols (RS-232, RS-422, RS-485 with optional modules)
- SCADA and HMI systems with analog or serial integration
- Standard industrial PLC networks
- Proportional and on-off control algorithms
- Third-party sensor and transmitter systems compatible with standard TC/RTD/4-20mA inputs


