The Bürkert Type 8693 is a digital electropneumatic process controller designed for direct integrated mounting onto the actuator bonnet of Bürkert Type 23xx and 2103 series hygienic process valves. It combines the functions of a valve positioner and a process controller (PID) in a single compact housing machined from PPS and stainless steel. The defining sensing technology is a contact-free inductive linear position sensor with 14-bit resolution — unlike traditional potentiometric positioners whose resistive tracks degrade with every actuator stroke, the inductive sensor operates without physical contact between the moving target and the stationary coil, eliminating a primary wear-out mechanism in high-cycle applications.

How does the Tune function simplify commissioning?

The built-in Tune function automatically characterizes the control valve's pneumatic response — fill time, exhaust time, stroke limits, and actuator dead zone — and calculates optimized PID parameters for both the position control loop and the process variable control loop. The technician mounts the 8693 onto the valve, connects the supply air and setpoint signal, and initiates Tune from the backlit graphic display and 4-key keypad. The controller exercises the valve through its full stroke range, measures the dynamic response, and stores the PID coefficients in non-volatile memory. No laptop, software, or pneumatic expertise is required at the valve. The same routine can be re-run after actuator or seal replacement to adapt to changed pneumatic characteristics.

What diagnostic information does it provide?

The 8693 implements NE 107 (NAMUR) valve diagnostics, continuously monitoring valve stroke count, cycle frequency, travel time, end-position deviation, and ambient temperature. Diagnostic status is presented as a standardized traffic-light symbol on the display — green (normal), yellow (maintenance required), orange (function check), and red (failure) — and is transmitted via the fieldbus or analogue feedback signal to the asset management system. A history log stores the last 200 diagnostic events with time stamps, enabling trend analysis for predictive maintenance. The controller draws zero internal air in steady state — pilot air is consumed only during valve movement — reducing compressed air costs in plants with hundreds of automated process valves.

What fieldbus and hazardous area options are available?

In addition to the standard analogue setpoint input (0/4–20 mA, 0–5/10 V, 0–1000 Hz, or Pt100 direct), the 8693 is available with factory-fitted fieldbus interfaces: PROFIBUS DP-V1, PROFINET, EtherNet/IP, Modbus TCP, or büS — the Bürkert System Bus based on CANopen. The büS variant enables daisy-chaining of multiple Bürkert devices on a single CAN trunk, reducing cable runs in valve-dense process skids. For hazardous area installations, the 8693 carries ATEX II 3G Ex ec IIC T4 Gc and II 3D Ex tc IIIC T135°C Dc certifications, plus IECEx, UL, and FM Class I Division 2 approvals, covering gas and dust atmospheres in Zone 2/22 locations.