The Schneider Electric/Eurotherm 818P4 is a 1/4 DIN digital temperature and process controller/programmer engineered for precise thermal process management in industrial applications. It delivers advanced programming capabilities with dual fluorescent 4½-digit displays for simultaneous setpoint and measured value monitoring, combined with PID control featuring self-tuning and adaptive tuning algorithms for optimal loop performance.
Technical Specifications
Form Factor & Display
• 1/4 DIN panel mount
• Dual fluorescent 4½-digit displays
Programming Capability
• Stores up to 4 independent programs
• Each program supports 8 ramp/dwell segments
• Programs linkable for extended sequences
• Up to 999 program repetitions or continuous run mode
Control & Tuning
• PID control with self-tuning and adaptive tuning
• Variable overshoot inhibition
• Adjustable holdback for loads with propagation delays
• Operation in °F, °C, or process units
Input Configuration
• Choice of 17 different thermocouple types, RTD, or process inputs
• Linear process inputs for standard signal ranges
• Remote setpoint, trim, or output power limit inputs
• Analog input for remote signal representation
• Input adapter available for signal ranges exceeding 50 mV
• Sensor break detection with adjustable sensor break power
Output Configuration
• Up to 4 multi-purpose configurable output channels
• Configurable as relay, triac, logic, or analog outputs
• Outputs 1 and 2 support heat/cool control
• Optional valve positioner configuration
• Analog retransmission of measured value, setpoint, error, or output level
• Program event relay outputs for specific program segments
Alarms
• Up to 2 configurable alarms
• Configurable as Full Scale High or Energised modes
Communications
• Fully isolated bidirectional EIA-232-D or EIA-485 (EIA-422-A) digital communications
• Supports Eurotherm Bi-Synch, J-bus, and Modbus protocols
• Transmission speed configurable between 300 and 9600 baud
• Optional separate digital communication interface board
Power Supply
• 85 to 264 V a.c. ~ or 17 to 40 V a.c. ~ or 20 to 40 V d.c.
• Supply frequency: 48 to 52 Hz or 58 Hz
– Key Features
• Front panel disable via digital input or communications interface
• User-friendly configuration and monitoring interface
• Reliable and repeatable performance across complex thermal processes
• Enhanced efficiency and product quality in industrial environments
– Typical Applications
Complex industrial thermal process control requiring programmable setpoint profiles, heat/cool regulation, and remote monitoring capabilities.
– Compatibility & Integration
Serial communications via RS232 or RS485 enable integration with supervisory control systems, data logging platforms, and networked industrial environments supporting standard Modbus, J-bus, or Eurotherm Bi-Synch protocols.
