Schneider Electric / Eurotherm 818P4 Temperature Controller / Programmer

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.