Spirax Sarco SX25 Process Controller

Description

Spirax Sarco SX25 Process Controller is a high-precision 1/16 DIN panel-mount controller from renowned UK steam system brand Spirax Sarco. Designed for constant setpoint applications, it integrates seamlessly with pneumatic (PN) and electric (EL) control valves and sensors. SX25 is suitable for temperature and pressure process control involving steam, water, or other industrial fluids. Advanced PID algorithms, adaptive tuning, and automatic tuning ensure stable system operation and precise control. SX25 series includes SX25 mA (linear mA output model) and SX25 VMD (valve motor drive model), enabling efficient process optimization without complex external configuration. It is widely used in industrial heating, cooling, and steam management systems. IP65 protection and electromagnetic compatibility design deliver reliable performance in harsh environments while helping reduce energy consumption and improve production efficiency.

Features

Advanced control algorithms: Supports PID control, including proportional band 0.5-999.9%, integral time 0.1-100.0 minutes (or off), derivative time 0.01-10.00 minutes (or off), and error band 0.1-10%. On-Off control provides 0.1-10% hysteresis and minimum overshoot functionality to protect critical processes from fluctuations.
Automatic and adaptive tuning: Single-shot tuning or natural frequency tuning allows the controller to intelligently select the best method according to process conditions. Adaptive tuning continuously optimizes PID parameters through non-intrusive analysis to improve control accuracy.
Universal input support: Compatible with resistance thermometers (Pt100, 2/3-wire), thermocouples (L, J, T, K, S, or custom), linear mA signals (4-20mA, 0-20mA), and voltage signals (0/10-50mV). Sampling time is only 500ms for real-time response. SX25 mA additionally provides auxiliary power (+18V ±20%, maximum 30mA) for loop-powered sensors.
Flexible output configuration: SX25 mA provides linear mA output (0/4-20mA, 0.1% accuracy) plus multiple relay/SSR outputs (2A/250Vac). SX25 VMD provides dual-relay valve drive, supporting 15-600 seconds of stroke time and a 0.1-5.0% minimum step. Two programmable relays support deviation, bandwidth, and process alarms with latching and blocking functions.
Convenient operation: Keypad switching between automatic and manual modes displays power output percentage. Two independent ramps (up/down) support smooth setpoint changes. IP65 front-panel protection, an operating temperature of 0-50°C, and relative humidity of 5-90% make SX25 suitable for industrial sites.
Safety and compatibility: Complies with EN 61010-1 safety standard and electromagnetic compatibility Directive 89/336/EEC, including radio-frequency emissions and immunity requirements. CE certification supports reliability and compliance.

Technical Specifications

Power requirements: 100-240Vac, 50/60Hz, maximum power consumption 1.6VA.
Input accuracy: RTD/thermocouple: 0.25% ±1 digit; linear mA: 1.25% ±1 digit; voltage: 0.10% ±1 digit (at 25°C ambient temperature).
Output details:

SX25 mA: 12-bit mA output resolution (0.025%), maximum load 750Ω; SPST normally open relay output, 2A/250Vac.

SX25 VMD: valve drive relay, 2x SPST normally open, 2A/250Vac.
Dimensions and installation: Panel cutout 45x45mm (+0.6mm), overall dimensions 48x48x120mm, approximate weight 130g. Screw-terminal connections; minimum depth 65mm.
Environmental suitability: 0-50°C operating temperature; suitable for non-explosive environments.

Installation and Maintenance Guide

Ensure accurate panel cutout dimensions during installation and verify power compatibility before connection. Electrical wiring must comply with applicable safety requirements, and electromagnetic interference should be avoided. Automatic tuning simplifies commissioning, and no routine maintenance is required; however, regular inspection of input signals and PID parameter calibration is recommended. In manual mode, output can be adjusted directly to test system response. Refer to the official manual for detailed installation procedures.